Publications by authors named "Iris C Gibbs"

113 Publications

Late effects of radiation therapy in pediatric patients and survivorship.

Pediatr Blood Cancer 2021 May;68 Suppl 2:e28349

Department of Radiation Oncology, University of Rochester, Rochester, New York.

Advances in multimodality therapy have led to childhood cancer cure rates over 80%. However, surgery, chemotherapy, and radiotherapy may lead to debilitating or even fatal long-term effects among childhood survivors beyond those inflicted by the primary disease process. It is critical to understand, mitigate, and prevent these late effects of cancer therapy to improve the quality of life of childhood cancer survivors. This review summarizes the various late effects of radiotherapy and acknowledges the Pediatric Normal Tissue Effects in the Clinic (PENTEC), an international collaboration that is systematically analyzing the association between radiation treatment dose/volume and consequential organ toxicities, in developing children as a basis to formulate recommendations for clinical practice of pediatric radiation oncology. We also summarize initiatives for survivorship and surveillance of late normal tissue effects related to radiation therapy among long-term survivors of childhood cancer treated in the past.
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http://dx.doi.org/10.1002/pbc.28349DOI Listing
May 2021

The Stanford stereotactic radiosurgery experience on 7000 patients over 2 decades (1999-2018): looking far beyond the scalpel.

J Neurosurg 2021 Apr 2:1-17. Epub 2021 Apr 2.

Departments of1Neurosurgery and.

Objective: The CyberKnife (CK) has emerged as an effective frameless and noninvasive method for treating a myriad of neurosurgical conditions. Here, the authors conducted an extensive retrospective analysis and review of the literature to elucidate the trend for CK use in the management paradigm for common neurosurgical diseases at their institution.

Methods: A literature review (January 1990-June 2019) and clinical review (January 1999-December 2018) were performed using, respectively, online research databases and the Stanford Research Repository of patients with intracranial and spinal lesions treated with CK at Stanford. For each disease considered, the coefficient of determination (r2) was estimated as a measure of CK utilization over time. A change in treatment modality was assessed using a t-test, with statistical significance assessed at the 0.05 alpha level.

Results: In over 7000 patients treated with CK for various brain and spinal lesions over the past 20 years, a positive linear trend (r2 = 0.80) in the system's use was observed. CK gained prominence in the management of intracranial and spinal arteriovenous malformations (AVMs; r2 = 0.89 and 0.95, respectively); brain and spine metastases (r2 = 0.97 and 0.79, respectively); benign tumors such as meningioma (r2 = 0.85), vestibular schwannoma (r2 = 0.76), and glomus jugulare tumor (r2 = 0.89); glioblastoma (r2 = 0.54); and trigeminal neuralgia (r2 = 0.81). A statistically significant difference in the change in treatment modality to CK was observed in the management of intracranial and spinal AVMs (p < 0.05), and while the treatment of brain and spine metastases, meningioma, and glioblastoma trended toward the use of CK, the change in treatment modality for these lesions was not statistically significant.

Conclusions: Evidence suggests the robust use of CK for treating a wide range of neurological conditions.
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http://dx.doi.org/10.3171/2020.9.JNS201484DOI Listing
April 2021

Stereotactic Body Radiation Therapy for Spinal Metastases: Tumor Control Probability Analyses and Recommended Reporting Standards.

Int J Radiat Oncol Biol Phys 2021 May 27;110(1):112-123. Epub 2021 Jan 27.

Department of Radiation Oncology, University of California at Davis, Sacramento, California.

Purpose: We sought to investigate the tumor control probability (TCP) of spinal metastases treated with stereotactic body radiation therapy (SBRT) in 1 to 5 fractions.

Methods And Materials: PubMed-indexed articles from 1995 to 2018 were eligible for data extraction if they contained SBRT dosimetric details correlated with actuarial 2-year local tumor control rates. Logistic dose-response models of collected data were compared in terms of physical dose and 3-fraction equivalent dose.

Results: Data were extracted from 24 articles with 2619 spinal metastases. Physical dose TCP modeling of 2-year local tumor control from the single-fraction data were compared with data from 2 to 5 fractions, resulting in an estimated α/β = 6 Gy, and this was used to pool data. Acknowledging the uncertainty intrinsic to the data extraction and modeling process, the 90% TCP corresponded to 20 Gy in 1 fraction, 28 Gy in 2 fractions, 33 Gy in 3 fractions, and (with extrapolation) 40 Gy in 5 fractions. The estimated TCP for common fractionation schemes was 82% at 18 Gy, 90% for 20 Gy, and 96% for 24 Gy in a single fraction, 82% for 24 Gy in 2 fractions, and 78% for 27 Gy in 3 fractions.

Conclusions: Spinal SBRT with the most common fractionation schemes yields 2-year estimates of local control of 82% to 96%. Given the heterogeneity in the tumor control estimates extracted from the literature, with variability in reporting of dosimetry data and the definition of and statistical methods of reporting tumor control, care should be taken interpreting the resultant model-based estimates. Depending on the clinical intent, the improved TCP with higher dose regimens should be weighed against the potential risks for greater toxicity. We encourage future reports to provide full dosimetric data correlated with tumor local control to allow future efforts of modeling pooled data.
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http://dx.doi.org/10.1016/j.ijrobp.2020.11.021DOI Listing
May 2021

Improved survival and disease control following pembrolizumab-induced immune-related adverse events in high PD-L1 expressing non-small cell lung cancer with brain metastases.

J Neurooncol 2021 Mar 7;152(1):125-134. Epub 2021 Jan 7.

Department of Neurosurgery, Stanford Medical Center, Palo Alto, CA, 94304, USA.

Introduction: Immune checkpoint inhibitors have become standard of care for many patients with non-small cell lung cancer (NSCLC). These agents often cause immune-related adverse events (IRAEs), which have been associated with increased overall survival (OS). Intracranial disease control and OS for patients experiencing IRAEs with metastatic NSCLC and brain metastases have not yet been described.

Methods: We performed a single-institution, retrospective review of patients with NSCLC and existing diagnosis of brain metastasis, who underwent pembrolizumab treatment and developed any grade IRAE. The primary outcome of the study was intracranial time to treatment failure (TTF), defined from time of pembrolizumab initiation to new intracranial disease progression or death. Kaplan-Meier and Cox proportional hazard analyses were performed.

Results: A total of 63 patients with NSCLC brain metastasis were identified, and 24 developed IRAEs. Patients with any grade IRAEs had longer OS (21 vs. 10 months, p = 0.004), systemic TTF (15 vs. 4 months, p < 0.001) and intracranial TTF (14 vs. 5 months, p = 0.001), relative to patients without IRAEs. Presence of IRAEs and high PD-L1 (≥ 50%), but not absent/moderate PD-L1 (0-49%), had a positive association for OS, systemic TTF, and intracranial TTF. Following multivariable analysis, IRAE experienced on pembrolizumab was an independent predictor of OS, systemic TTF, and intracranial TTF.

Conclusions: In our series of patients with NSCLC and brain metastases treated with pembrolizumab, IRAE presence was associated with a significant increase in OS, systemic TTF, and intracranial TTF. Future studies with increased cohorts will clarify how IRAEs should be interpreted among molecular subtypes.
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http://dx.doi.org/10.1007/s11060-020-03686-3DOI Listing
March 2021

A multi-institutional phase 2 trial of stereotactic body radiotherapy in the treatment of bone metastases in pediatric and young adult patients with sarcoma.

Cancer 2021 Mar 10;127(5):739-747. Epub 2020 Nov 10.

Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Background: Metastasectomy is standard of care for pediatric patients with metastatic sarcoma with limited disease. For patients with unresectable disease, stereotactic body radiotherapy (SBRT) may serve as an alternative. Herein, the authors report the results of a prospective, multi-institutional phase 2 trial of SBRT in children and young adults with metastatic sarcoma.

Methods: Patients aged >3 years and ≤40 years with unresected, osseous metastatic nonrhabdomyosarcoma sarcomas of soft tissue and bone were eligible. Patients received SBRT to a dose of 40 Gray (Gy) in 5 fractions. Local control (LC), progression-free survival (PFS), and overall survival (OS) were calculated using the Kaplan-Meier method.

Results: Fourteen patients with a median age of 17 years (range, 4-25 years) were treated to 37 distinct metastatic lesions. With a median follow-up of 6.8 months (30.5 months in surviving patients), the Kaplan-Meier patient-specific and lesion-specific LC rates at 6 months were 89% and 95%, respectively. The median PFS was 6 months and the median OS was 24 months. In a post hoc analysis, PFS (median, 9.3 months vs 3.7 months; log-rank P = .03) and OS (median not reached vs 12.7 months; log-rank P = .02) were improved when all known sites of metastatic disease were consolidated with SBRT compared with partial consolidation. SBRT was well tolerated, with 2 patients experiencing grade 3 toxicities.

Conclusions: SBRT achieved high rates of LC in pediatric patients with inoperable metastatic nonrhabdomyosarcoma sarcomas of soft tissue and bone. These results suggest that the ability to achieve total consolidation of metastatic disease with SBRT is associated with improved PFS and OS.
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http://dx.doi.org/10.1002/cncr.33306DOI Listing
March 2021

In Response to Comment On: Why Racial Justice Matters in Radiation Oncology.

Adv Radiat Oncol 2020 Sep-Oct;5(5):797. Epub 2020 Aug 18.

Department of Radiation Oncology, Wake Forest School of Medicine, Winston Salem, North Carolina.

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http://dx.doi.org/10.1016/j.adro.2020.07.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7557179PMC
August 2020

Stereotactic Radiotherapy and Resection of Brain Metastases: The Role of Hypofractionation.

JAMA Oncol 2020 Oct 15. Epub 2020 Oct 15.

Department of Radiation Oncology, Stanford School of Medicine, Palo Alto, California.

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http://dx.doi.org/10.1001/jamaoncol.2020.4400DOI Listing
October 2020

Virtual Radiation Oncology Clerkship During the COVID-19 Pandemic and Beyond.

Int J Radiat Oncol Biol Phys 2020 10;108(2):444-451

Department of Radiation Oncology, Stanford School of Medicine, Stanford, California. Electronic address:

Purpose: We evaluated the impact of a virtual radiation oncology clerkship.

Methods And Materials: We developed a 2-week virtual radiation oncology clerkship that launched on April 27, 2020. Clerkship components included a virtual clinic with radiation oncology faculty and residents, didactic lectures, student talks, and supplemental sessions such as tumor boards and chart rounds. Medical students completed pre- and post-clerkship self-assessments. Faculty and resident participants also completed surveys on their experience with virtual lectures and clinics. Pre- and post-clerkship results were compared using a 2-sided paired t test. An analysis of variance model was used to analyze the clerkship components.

Results: Twenty-six medical students, including 4 visiting students, enrolled over 2 clerkship periods (4 weeks). All students completed the pre- and post-clerkship self-assessments and agreed that the clerkship improved their understanding of radiation oncology. Compared with 3 (11.5%) students who agreed that they understood the daily responsibilities of a radiation oncologist before the clerkship, 22 (84.6%) students agreed and 3 (11.5%) strongly agreed that they understood the daily responsibilities of a radiation oncologist after the clerkship (P < .0001). Although 15 students (57.7%) reported an increased interest in radiation oncology because of the clerkship, the mean level of interest in radiation oncology as a career remained the same, with pre- and post-clerkship scores of 3.0 (±0.9) and 3.0 (±1.1) on a 5-point scale, respectively (P = .7). Students found virtual clinic and didactic lectures to be the most valuable components of the clerkship. Most respondents agreed (30.8%) or strongly agreed (65.4%) to recommend the clerkship to their classmates.

Conclusions: Our virtual clerkship was effective in increasing medical student interest in and knowledge about radiation oncology. These data will help optimize a new paradigm of virtual radiation oncology education for medical students during COVID-19 and beyond.
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http://dx.doi.org/10.1016/j.ijrobp.2020.06.050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7462792PMC
October 2020

Intracranial Tumor Control After Immune-Related Adverse Events and Discontinuation of Immunotherapy for Melanoma.

World Neurosurg 2020 Dec 24;144:e316-e325. Epub 2020 Aug 24.

Department of Neurosurgery, Stanford Medical Center, Palo Alto, California, USA. Electronic address:

Objective: Immunotherapy for patients with melanoma with brain metastasis has significantly improved outcomes; however, it has also been characterized by potentially dangerous immune-related adverse events (IRAEs). Several reports have suggested that these reactions can precede improved treatment responses. For intracranial disease control, we sought to identify if such an association exists.

Methods: We conducted a retrospective chart review of patients with melanoma who underwent immunotherapy treatment after diagnosis of brain metastasis. The study cohort was then stratified into 2 groups based on their history of developing an IRAE that prompted discontinuation of that regimen. The primary outcome variable included intracranial progression-free survival (PFS). Kaplan-Meier and Cox proportional hazard analyses were used to evaluate survival and predictors of outcomes.

Results: Fifty-two patients met the inclusion criteria, 17 of whom experienced severe IRAEs that led to discontinuation of immunotherapy. Median intracranial PFS was 19.9 versus 10.5 months (P = 0.053) in patients who did and did not experience severe IRAEs prompting discontinuation, respectively. No additional outcome benefits were identified for systemic PFS or overall survival (mean, 33.1 months and 27.6 months, respectively). Multivariable analysis identified BRAF mutation status as a negative prognosticator of brain progression (P = 0.013; hazard ratio, 3.90). Initial treatment with BRAF inhibitor was also a negative predictor of all-cause mortality (P = 0.015; hazard ratio, 10.73).

Conclusions: Immune-related adverse events may signify an underlying immunogenic response that has intracranial disease control benefits. Despite their associated side effects, immunotherapies continue to show promising outcomes as a first-line agent for melanoma with brain metastasis.
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http://dx.doi.org/10.1016/j.wneu.2020.08.124DOI Listing
December 2020

Why Racial Justice Matters in Radiation Oncology.

Adv Radiat Oncol 2020 Sep-Oct;5(5):783-790. Epub 2020 Jul 7.

Department of Radiation Oncology, Wake Forest School of Medicine, Winston Salem, North Carolina.

Recent events have reaffirmed that racism is a pervasive disease plaguing the United States and infiltrating the fabric of this nation. As health care professionals dedicated to understanding and alleviating disease, many radiation oncologists have failed to acknowledge how structural racism affects the health and well-being of the patients we aim to serve. The literature is full of descriptive statistics showing the higher incidence and mortality experienced by the Black population for health conditions ranging from infant mortality to infectious disease, including coronavirus disease 2019 (COVID-19). Acknowledgment that the root of health disparities experienced by Black people in this country are based in racism is essential to moving the nation and the field of radiation oncology forward. With this lens, a brief overview of structural and institutional racism shapes a discussion of what radiation oncologists and the organizations that represent them can do to address this scourge. As members of a technological field, we often harness the power of data to advance human health and approach challenging diseases with optimism that multidisciplinary effort can produce cure. A few principles to mitigate the longstanding issues of Black marginalization within the field have been recommended via the ATIP (Acknowledgment, Transparency, Intentionality, and rePresentation) and LEADS (Learn, Engage, Advocate, Defend, Support) approaches. However, additional introspection is encouraged. Just as individuals, practices, and organizations rallied to determine how best to address the issues related to the COVID-19 pandemic, the same investigational fervor must be applied to the issue of racism to combat this sinister and often deadly disease.
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http://dx.doi.org/10.1016/j.adro.2020.06.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7340406PMC
July 2020

I Can't Breathe: The Continued Disproportionate Exclusion of Black Physicians in the United States Radiation Oncology Workforce.

Int J Radiat Oncol Biol Phys 2020 11 12;108(4):856-863. Epub 2020 Jul 12.

Department of Radiation Oncology, Stanford University, Stanford, California.

Purpose: Black physicians remain disproportionately underrepresented in certain medical specialties, yet comprehensive assessments in radiation oncology (RO) are lacking. Our purpose was to report current and historical representation trends for Black physicians in the US RO workforce.

Methods And Materials: Public registries were used to assess significant differences in 2016 representation for US vs RO Black academic full-time faculty, residents, and applicants. Historical changes from 1970 to 2016 were reported descriptively. Linear regression was used to assess significant changes for Black residents and faculty from 1995 to 2016.

Results: In 2016, Black people represented 3.2% vs 1.5% (P < .001), 5.6% vs 3.2% (P = .005), and 6.5% vs 5.4% (P = .352) of US vs RO faculty, residents, and applicants, respectively. Although RO residents nearly doubled from 374 (1974) to 720 (2016), Black residents peaked at 31 in 1984 (5.9%; 31 of 522) and fell to 23 (3.2%; 23 of 720) in 2016 across 91 accredited programs; Black US graduate medical education trainees nearly doubled over the same period: 3506 (1984) to 6905 (2016). From 1995 to 2016, Black US resident representation significantly increased by 0.03%/y, but decreased significantly in RO by -0.20%/y before 2006 and did not change significantly thereafter. Over the same period, Black US faculty representation significantly increased by 0.02%/y, whereas Black RO faculty significantly increased by 0.07%/y before 2006, then decreased significantly by -0.16%/y thereafter. The number of Black RO faculty peaked at 37 in 2006 (3.1%; 37 of 1203) and was 27 (1.5%; 27 of 1769) in 2016, despite the nearly 1.5-fold increase in the number of both RO faculty and Black US faculty overall (4169 in 2006 and 6047 in 2016) during that period.

Conclusions: Black physicians remain disproportionately underrepresented in RO despite an increasing available pipeline in the US physician workforce. Deliberate efforts to understand barriers to specialty training and inclusion, along with evidence-based targeted interventions to overcome them, are needed to ensure diversification of the RO physician workforce.
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http://dx.doi.org/10.1016/j.ijrobp.2020.07.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7354371PMC
November 2020

Stereotactic Radiosurgery for Resected Brain Metastases: Does the Surgical Corridor Need to be Targeted?

Pract Radiat Oncol 2020 Sep - Oct;10(5):e363-e371. Epub 2020 May 16.

Departments of Radiation Oncology, Stanford, California. Electronic address:

Purpose: Although consensus guidelines for postresection stereotactic radiosurgery (SRS) for brain metastases recommend the surgical corridor leading to the resection cavity be included in the SRS plan, no study has reported patterns of tumor recurrence based on inclusion or exclusion of the corridor as a target. We reviewed tumor control and toxicity outcomes of postresection SRS for deep brain metastases based on whether or not the surgical corridor was targeted.

Materials And Methods: We retrospectively reviewed patients who had resected brain metastases treated with SRS between 2007 and 2018 and included only "deep" tumors (defined as located ≥1.0 cm from the pial surface before resection).

Results: In 66 deep brain metastases in 64 patients, the surgical corridor was targeted in 43 (65%). There were no statistical differences in the cumulative incidences of progression at 12 months for targeting versus not targeting the corridor, respectively, for overall local failure 2% (95% confidence interval [CI], 0%-11%) versus 9% (95% CI, 1%-25%; P = .25), corridor failure 0% (95% CI, 0%-0%) versus 9% (95% CI, 1%-25%; P = .06), cavity failure 2% (95% CI, 0%-11%) versus 0% (95% CI, 0%-0%; P = .91), and adverse radiation effect 5% (95% CI, 1%-15%) versus 13% (95% CI, 3%-30%; P = .22). Leptomeningeal disease (7%; 95% CI, 2%-18%) versus 26% (95% CI, 10%-45%; P = .03) was higher in those without the corridor targeted.

Conclusions: Omitting the surgical corridor in postoperative SRS for resected brain metastases was not associated with statistically significant differences in corridor or cavity recurrence or adverse radiation effect. As seen in recent prospective trials of postresection SRS, the dominant pattern of progression is within the resection cavity; omission of the corridor would yield a smaller SRS volume that could allow for dose escalation to potentially improve local cavity control.
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http://dx.doi.org/10.1016/j.prro.2020.04.009DOI Listing
May 2020

Evaluating Surgical Resection Extent and Adjuvant Therapy in the Management of Gliosarcoma.

Front Oncol 2020 11;10:337. Epub 2020 Mar 11.

Department of Neurosurgery, Stanford University Medical Center, Stanford, CA, United States.

Gliosarcomas are clinically aggressive tumors, histologically distinct from glioblastoma. Data regarding the impact of extent of resection and post-operative adjuvant therapy on gliosarcoma outcomes are limited. Patients with histologically confirmed gliosarcoma diagnosed between 1999 and 2019 were identified. Clinical, molecular, and radiographic data were assembled based on historical records. Comparisons of categorical variables used Pearson's Chi-square and Fisher's exact test while continuous values were compared using the Wilcoxon signed-rank test. Survival comparisons were assessed using Kaplan-Meier statistics and Cox regressions. Seventy-one gliosarcoma patients were identified. Secondary gliosarcoma was not associated with worse survival when compared to recurrent primary gliosarcoma (median survival 9.8 [3.8 to 21.0] months vs. 7.6 [1.0 to 35.7], = 0.7493). On multivariable analysis, receipt of temozolomide (HR = 0.02, 95% CI 0.001-0.21) and achievement of gross total resection (GTR; HR = 0.13, 95% CI 0.02-0.77) were independently prognostic for improved progression-free survival (PFS) while only receipt of temozolomide was independently associated with extended overall survival (OS) (HR = 0.03, 95% CI 0.001-0.89). In patients receiving surgical resection followed by radiotherapy and concomitant temozolomide, achievement of GTR was significantly associated with improved PFS (median 32.97 [7.1-79.6] months vs. 5.45 [1.8-26.3], = 0.0092) and OS (median 56.73 months [7.8-104.5] vs. 14.83 [3.8 to 29.1], = 0.0252). Multimodal therapy is associated with improved survival in gliosarcoma. Even in patients receiving aggressive post-operative multimodal management, total surgical removal of macroscopic disease remains important for optimal outcomes.
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http://dx.doi.org/10.3389/fonc.2020.00337DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078164PMC
March 2020

Local control and toxicity outcomes of stereotactic radiosurgery for spinal metastases of gastrointestinal origin.

J Neurosurg Spine 2020 Mar 6:1-8. Epub 2020 Mar 6.

Departments of1Radiation Oncology and.

Objective: Colorectal cancer (CRC) and other gastrointestinal (GI) cancers are believed to have greater radioresistance than other histologies. The authors report local control and toxicity outcomes of stereotactic radiosurgery (SRS) to spinal metastases from GI primary cancers.

Methods: A retrospective single-center review was conducted of patients with spinal metastases from GI primary cancers treated with SRS from 2004 to 2017. Patient demographics and lesion characteristics were summarized using medians, interquartile ranges (IQRs), and proportions. Local failure (LF) was estimated using the cumulative incidence function adjusted for the competing risk of death and compared using Gray's test for equality. Multivariable analyses were conducted using Cox proportional hazard models, adjusting for death as a competing risk, on a per-lesion basis. Patients were stratified in the Cox model to account for repeated measures for clustered outcomes. Median survival was calculated using the Kaplan-Meier method.

Results: A total of 74 patients with 114 spine lesions were included in our analysis. The median age of the cohort was 62 years (IQR 53-70 years). Histologies included CRC (46%), hepatocellular carcinoma (19%), neuroendocrine carcinoma (13%), pancreatic carcinoma (12%), and other (10%). The 1- and 2-year cumulative incidence rates of LF were 24% (95% confidence interval [CI] 16%-33%) and 32% (95% CI 23%-42%), respectively. Univariable analysis revealed that older age (p = 0.015), right-sided primary CRCs (p = 0.038), and single fraction equivalent dose (SFED; α/β = 10) < 20 Gy (p = 0.004) were associated with higher rates of LF. The 1-year cumulative incidence rates of LF for SFED < 20 Gy10 versus SFED ≥ 20 Gy10 were 35% and 7%, respectively. After controlling for gross tumor volume and prior radiation therapy to the lesion, SFED < 20 Gy10 remained independently associated with worse LF (hazard ratio 2.92, 95% CI 1.24-6.89, p = 0.014). Toxicities were minimal, with pain flare observed in 6 patients (8%) and 15 vertebral compression fractures (13%).

Conclusions: Spinal metastases from GI primary cancers have high rates of LF with SRS at a lower dose. This study found that SRS dose is a significant predictor of failure and that prescribed SFED ≥ 20 Gy10 (biological equivalent dose ≥ 60 Gy10) is associated with superior local control.
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http://dx.doi.org/10.3171/2020.1.SPINE191260DOI Listing
March 2020

A phase I/II trial of 5-fraction stereotactic radiosurgery with 5-mm margins with concurrent temozolomide in newly diagnosed glioblastoma: primary outcomes.

Neuro Oncol 2020 08;22(8):1182-1189

Department of Radiation Oncology, Stanford University, Stanford, California, USA.

Background: We sought to determine the maximum tolerated dose (MTD) of 5-fraction stereotactic radiosurgery (SRS) with 5-mm margins delivered with concurrent temozolomide in newly diagnosed glioblastoma (GBM).

Methods: We enrolled adult patients with newly diagnosed glioblastoma to 5 days of SRS in a 3 + 3 design on 4 escalating dose levels: 25, 30, 35, and 40 Gy. Dose limiting toxicity (DLT) was defined as Common Terminology Criteria for Adverse Events grades 3-5 acute or late CNS toxicity, including adverse radiation effect (ARE), the imaging correlate of radiation necrosis.

Results: From 2010 to 2015, thirty patients were enrolled. The median age was 66 years (range, 51-86 y). The median target volume was 60 cm3 (range, 14.7-137.3 cm3). DLT occurred in 2 patients: one for posttreatment cerebral edema and progressive disease at 3 weeks (grade 4, dose 40 Gy); another patient died 1.5 weeks following SRS from postoperative complications (grade 5, dose 40 Gy). Late grades 1-2 ARE occurred in 8 patients at a median of 7.6 months (range 3.2-12.6 mo). No grades 3-5 ARE occurred. With a median follow-up of 13.8 months (range 1.7-64.4 mo), the median survival times were: progression-free survival, 8.2 months (95% CI: 4.6-10.5); overall survival, 14.8 months (95% CI: 10.9-19.9); O6-methylguanine-DNA methyltransferase hypermethylated, 19.9 months (95% CI: 10.5-33.5) versus 11.3 months (95% CI: 8.9-17.6) for no/unknown hypermethylation (P = 0.03), and 27.2 months (95% CI: 11.2-48.3) if late ARE occurred versus 11.7 months (95% CI: 8.9-17.6) for no ARE (P = 0.08).

Conclusions: The per-protocol MTD of 5-fraction SRS with 5-mm margins with concurrent temozolomide was 40 Gy in 5 fractions. ARE was limited to grades 1-2 and did not statistically impact survival.
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http://dx.doi.org/10.1093/neuonc/noaa019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594571PMC
August 2020

Stereotactic Radiosurgery for Resected Brain Metastases: Single-Institutional Experience of Over 500 Cavities.

Int J Radiat Oncol Biol Phys 2020 03 27;106(4):764-771. Epub 2019 Nov 27.

Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California. Electronic address:

Purpose: Postoperative stereotactic radiosurgery (SRS) has less detrimental effect on cognition and quality of life compared with whole brain radiation therapy (WBRT) and is increasingly used for resected brain metastases (BMs). Postoperative SRS techniques are not standardized, and there is a concern for a different pattern of failure after postoperative SRS compared with WBRT. We aim to study the efficacy, toxicity, and failure pattern of postoperative SRS.

Methods And Materials: We retrospectively reviewed outcomes of patients with resected BMs treated with postoperative SRS between 2007 and 2018. Overall survival and cumulative incidences of local failure, overall distant intracranial failure (distant parenchymal failure, nodular leptomeningeal disease [nLMD], classical leptomeningeal disease [cLMD]), and adverse radiation effect were reported. Neurologic death was determined for patients with leptomeningeal disease (LMD).

Results: A total of 442 patients with 501 resected BMs were treated over 475 total SRS courses. Median clinical follow-up and overall survival after SRS were 10.1 months (interquartile range, 3.6-20.7 months) and 13.9 months (95% confidence interval [CI], 11.8-15.2 months), respectively. At 12 months, event rates were 7% (95% CI, 5%-10%) for local failure, 9% (95% CI, 7%-12%) for adverse radiation effect, 44% (95% CI, 40%-49%) for overall distant intracranial failure, 37% (95% CI, 33%-42%) for distant parenchymal failure, and 13% (95% CI, 10%-17%) for LMD. The overall incidence of LMD was 15.8% (53% cLMD, 46% nLMD). cLMD was associated with shorter survival than nLMD (2.0 vs 11.2 months, P < .01) and a higher proportion of neurologic death (67% vs 41%, P = .02). A total of 15% of patients ultimately received WBRT.

Conclusions: We report the largest clinical experience of postoperative SRS for resected BMs, showing excellent local control and low toxicity. Intracranial failure was predominantly distant, with a rising incidence of LMD.
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http://dx.doi.org/10.1016/j.ijrobp.2019.11.022DOI Listing
March 2020

Stereotactic Radiosurgery for Pediatric and Adult Intracranial and Spinal Ependymomas.

Stereotact Funct Neurosurg 2019 7;97(3):189-194. Epub 2019 Oct 7.

Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California, USA.

Objective/background: We report efficacy and toxicity outcomes with stereotactic radiosurgery (SRS) for intracranial and spinal ependymoma.

Methods: We analyzed adult and pediatric patients with newly diagnosed or recurrent intracranial or spinal ependymoma lesions treated with SRS at our institution. Following SRS, local failure (LF) was defined as failure within or adjacent to the SRS target volume, while distant failure (DF) was defined as failure outside of the SRS target volume. Time to LF and DF was analyzed using competing risk analysis with death as a competing risk.Overall survival (OS) was calculated from the date of first SRS to the date of death or censored at the date of last follow-up using the Kaplan-Meier method.

Results: Twenty-one patients underwent SRS to 40 intracranial (n = 30) or spinal (n = 10) ependymoma lesions between 2007 and 2018, most commonly with 18 or 20 Gy in 1 fraction. Median follow-up for all patients after first SRS treatment was 54 months (range 2-157). The 1-year, 2-year, and 5-year rates of survival among patients with initial intracranial ependymoma were 86, 74, and 52%, respectively. The 2-year cumulative incidences of LF and DF after SRS among intracranial ependymoma patients were 25% (95% CI 11-43) and 42% (95% CI 22-60), respectively. No spinal ependymoma patient experienced LF, DF, or death within 2 years of SRS. Three patients had adverse radiation effects.

Conclusions: SRS is a viable treatment option for intracranial and spinal ependymoma with excellent local control and acceptable toxicity.
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http://dx.doi.org/10.1159/000502653DOI Listing
February 2020

Successful use of frameless stereotactic radiosurgery for treatment of recurrent brain metastases in an 18-month-old child.

Int J Neurosci 2019 Dec 20;129(12):1234-1239. Epub 2019 Aug 20.

Department of Radiation Oncology, Stanford University , Stanford , CA , USA.

There are very few reported cases of stereotactic radiosurgery (SRS) delivered in children under 3 years of age. We report an 18-month-old boy with metastatic recurrence of undifferentiated round cell sarcoma to the brain which was treated with chemotherapy, resection and robotic frameless SRS. Frameless SRS was delivered without technical difficulties, acute adverse events, or clinical sequelae 1.5 months post-radiation. Longer term follow-up will be needed to evaluate local tumor control and effects on neurocognitive development, endocrine function and growth. This report adds to the literature of the few reported cases of successfully attempted SRS in very young children.
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http://dx.doi.org/10.1080/00207454.2019.1655015DOI Listing
December 2019

Adverse Radiation Effect and Disease Control in Patients Undergoing Stereotactic Radiosurgery and Immune Checkpoint Inhibitor Therapy for Brain Metastases.

World Neurosurg 2019 Jun 20;126:e1399-e1411. Epub 2019 Mar 20.

Department of Radiation Oncology, Stanford Cancer Institute, Stanford, California, USA. Electronic address:

Background: Immune checkpoint inhibitors (ICIs) and stereotactic radiosurgery (SRS) are increasingly used together to manage brain metastases (BMs). We assessed adverse radiation effect, disease control, and overall survival in patients with BMs who received SRS with anticytotoxic T-lymphocyte-associated protein 4 and/or anti- programmed cell death protein receptor/ligand therapies.

Methods: We retrospectively reviewed the records of patients with intact or resected BMs treated with SRS and ICIs within 5 months of SRS between 2010 and 2018. Patients were defined as receiving concurrent SRS and ICI if a dose of ICI was given within 4 weeks of SRS. Local failure, distant intracranial failure, extracranial failure, and adverse radiation effect were assessed using cumulative incidence rates and competing risk regressions with death as a competing risk. Overall survival was assessed using the Kaplan-Meier method and Cox proportional hazards models.

Results: A total of 97 patients with 580 BMs were included in our analysis. Competing risk analyses showed that concurrent SRS-ICI therapy is associated with higher rates of adverse radiation effect (6.4% vs. 2.0% at 1 year; multivariable hazard ratio [HR], 4.47; 95% confidence interval [CI], 1.57-12.73; P = 0.005), lower rates of extracranial failure (69.7% vs. 80.8% at 1 year; multivariable HR, 0.60; 95% CI, 0.42-0.87; P = 0.007), and better overall survival (48.6% vs. 25.4% at 1 year; multivariable HR, 0.57; 95% CI, 0.33-0.99; P = 0.044) compared with nonconcurrent therapy. SRS-ICI timing was not associated with local failure or distant intracranial failure.

Conclusions: Concurrent SRS-ICI therapy has a tolerable adverse event profile and may improve extracranial disease control and overall survival, supporting concurrent use in the management of BMs.
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http://dx.doi.org/10.1016/j.wneu.2019.03.110DOI Listing
June 2019

Long-term follow up data on difficult to treat intracranial arteriovenous malformations treated with the CyberKnife.

J Clin Neurosci 2019 Mar 23;61:120-123. Epub 2018 Dec 23.

Department of Neurological Surgery, Stanford Medical Center, Stanford University, Palo Alto, CA, USA.

Introduction: The CyberKnife, a frameless, robotic, stereotactic device, has been developed to radiosurgically treat arteriovenous malformations (AVMs). While most AVMs are obliterated within two-to-three years, a subset remain recalcitrant; long-term data on these difficult to treat AVMs are limited in the neurosurgical literature.

Materials And Methods: A retrospective analysis of all patients who underwent CyberKnife treatment for intracranial AVMs at a single U.S. institution between 2002 and 2012, whose AVMs had failed to obliterate within 48 months or longer from the treatment start date, were eligible for inclusion.

Results: Eleven patients (9 AVMs; 7 males, 2 females) were followed for an average of 85.2 months (range 56.2-119.4). The median lesion size was 3.5 cm (range: 2.8-8.0 cm) and median Spetzler-Martin grade was 3 (range: 2-5). All AVMs were treated with one radiation dose (median prescribed dose was 18.0 Gy; median D: 23.7 Gy). Six (66.7%) were obliterated in a median time of 84 months (range: 52-94 months), while 3 (33.3%) remained active after a median of 90.8 months (range 69.7-119.4). Transient, post-radiosurgery adverse radiation effects occurred in 5 (55.6%) cases. One (11.1%) patient had an acute hemorrhage from the AVM after radiosurgery. Four (44.4%) patients underwent repeat radiosurgery and/or embolization. Three of these lesions eventually obliterated, while 1 did not.

Conclusion: The median time to obliteration was 84 months. Two-thirds of AVMs which persisted for over 4 years following initial radiosurgery treatment eventually obliterated. Transient post-radiosurgery adverse effects were common; delayed hemorrhages were rare in our case series.
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http://dx.doi.org/10.1016/j.jocn.2018.10.109DOI Listing
March 2019

Long-Term Update of Stereotactic Radiosurgery for Benign Spinal Tumors.

Neurosurgery 2019 11;85(5):708-716

Department of Radiation Oncology, Stanford Cancer Institute, Stanford, California.

Background: Stereotactic radiosurgery (SRS) for benign intracranial tumors is an established standard of care. The widespread implementation of SRS for benign spinal tumors has been limited by lack of long-term data.

Objective: To update our institutional experience of safety and efficacy outcomes after SRS for benign spinal tumors.

Methods: We performed a retrospective cohort study of 120 patients with 149 benign spinal tumors (39 meningiomas, 26 neurofibromas, and 84 schwannomas) treated with SRS between 1999 and 2016, with follow-up magnetic resonance imaging available for review. The primary endpoint was the cumulative incidence of local failure (LF), with death as a competing risk. Secondary endpoints included tumor shrinkage, symptom response, toxicity, and secondary malignancy.

Results: Median follow-up was 49 mo (interquartile range: 25-103 mo, range: 3-216 mo), including 61 courses with >5 yr and 24 courses with >10 yr of follow-up. We observed 9 LF for a cumulative incidence of LF of 2%, 5%, and 12% at 3, 5, and 10 yr, respectively. Excluding 10 tumors that were previously irradiated or that arose within a previously irradiated field, the 3-, 5-, and 10-yr cumulative incidence rates of LF were 1%, 2%, and 8%, respectively. At last follow-up, 35% of all lesions had decreased in size. With a total of 776 patient-years of follow-up, no SRS-related secondary malignancies were observed.

Conclusion: Comparable to SRS for benign intracranial tumors, SRS provides longer term local control of benign spinal tumors and is a standard-of-care alternative to surgical resection.
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http://dx.doi.org/10.1093/neuros/nyy442DOI Listing
November 2019

Long-Term Hearing Outcomes Following Stereotactic Radiosurgery in Vestibular Schwannoma Patients-A Retrospective Cohort Study.

Neurosurgery 2019 10;85(4):550-559

Department of Otolaryngology, Head and Neck Surgery, Stanford University, Palo Alto, California.

Background: An understanding of the hearing outcomes is needed for treatment counseling for patients with vestibular schwannomas (VS).

Objective: To determine long-term hearing results following stereotactic radiosurgery (SRS) for VS and identify any influential variables.

Methods: Tertiary hospital retrospective cohort.

Results: There were 579 tumors (576 patients) treated with SRS. Eighty-two percent (473) of tumors had ≥1 yr and 59% (344 ≥3 yr follow-up. In the 244 tumor ears, with measurable hearing before SRS who were followed ≥1 yr, 14% (31) had improved hearing, 13% (29) unchanged hearing, and 74% (158) had worsened hearing. In 175 patients with ≥3 yr follow-up and who had measurable hearing pretreatment, 6% (11 ears) improved hearing, 31% (54 ears) unchanged hearing, and 63% (110 ears) had worsened hearing. Patients with tumors with larger target volumes (P = .040) and with neurofibromatosis type 2 (NF2; P = .017) were associated with poorer hearing (P = .040). Patients with word recognition scores (WRS) of 50% or poorer had tumors with a larger volume (P = .0002), larger linear size (P = .032), and NF2 (P = .045). Traditionally reported hearing outcomes using the Gardner Robertson maintenance of PTA ≤50 db or WRS ≥50% were 48% at 3 yr, which overestimates hearing outcomes compared to the above reporting standards.

Conclusion: Hearing declines over time in VS treated with SRS in a high proportion of cases. The frequency and magnitude of long-term hearing decline following SRS argues against prophylactic radiation for small tumors in hearing ears with undetermined growth behavior.
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http://dx.doi.org/10.1093/neuros/nyy407DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7137466PMC
October 2019

Survival impact of postoperative radiotherapy timing in pediatric and adolescent medulloblastoma.

Neuro Oncol 2018 07;20(8):1133-1141

Department of Radiation Oncology, Stanford University Medical Center, Stanford, California.

Background: Radiation therapy (RT) remains a critical component of multimodality treatment for medulloblastoma. Traditionally, clinicians strive to start RT within 4-5 weeks of surgery, but the optimal timing after surgery remains unclear.

Methods: Using the National Cancer Database, we identified pediatric and adolescent patients with medulloblastoma treated with curative-intent surgery, RT, and chemotherapy. Factors associated with early or delayed RT were identified using Pearson chi-squared tests. Overall survival (OS) differences based on RT timing were compared using the Kaplan-Meier estimator with log-rank tests. Patient, tumor, and treatment characteristics associated with OS were analyzed with univariate and multivariate Cox proportional hazards models.

Results: Among the 1338 patients analyzed, early RT (defined as initiation ≤3 wk after surgery) was associated with younger age, M1-3 disease, and subtotal resection. Patients who initiated RT early had decreased 5-year OS compared with patients who initiated RT 3.1-4, 4.1-5, or >5 weeks after surgery (72.5% vs. 80.5%, 79.4%, and 77.8%, respectively; P = 0.019), but there was no significant difference in OS among the latter 3 groups (P = 0.788). On multivariate analysis, early RT versus the 3.1- to 4-week interval was significantly associated with poorer OS (adjusted hazard ratio, 1.72; 95% CI: 1.19-2.48; P = 0.004), while time to RT of >5 weeks but within 90 days of surgery did not adversely impact OS (P = 0.563).

Conclusions: In this large national database analysis, delaying RT within 90 days of surgery was not associated with inferior outcomes. Although clinical judgment remains paramount, postoperative RT timing should allow for healing and the development of an optimal treatment plan.
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http://dx.doi.org/10.1093/neuonc/noy001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6280134PMC
July 2018

Imaging changes over 18 months following stereotactic radiosurgery for brain metastases: both late radiation necrosis and tumor progression can occur.

J Neurooncol 2018 Jan 2;136(1):207-212. Epub 2017 Nov 2.

Department of Radiation Oncology, Stanford Cancer Institute, Stanford University, 875 Blake Wilbur Drive, Stanford, CA, 94305-5847, USA.

Following stereotactic radiosurgery (SRS) for brain metastases, the median time range to develop adverse radiation effect (ARE) or radiation necrosis is 7-11 months. Similarly, the risk of local tumor recurrence following SRS is < 5% after 18 months. With improvements in systemic therapy, patients are living longer and are at risk for both late (defined as > 18 months after SRS) tumor recurrence and late ARE, which have not previously been well described. An IRB-approved, retrospective review identified patients treated with SRS who developed new MRI contrast enhancement > 18 months following SRS. ARE was defined as stabilization/shrinkage of the lesion over time or pathologic confirmation of necrosis, without tumor. Local failure (LF) was defined as continued enlargement of the lesion over time or pathologic confirmation of tumor. We identified 16 patients, with a median follow-up of 48.2 months and median overall survival of 73.0 months, who had 19 metastases with late imaging changes occurring a median of 32.9 months (range 18.5-63.2 months) after SRS. Following SRS, 12 lesions had late ARE at a median of 33.2 months and 7 lesions had late LF occurring a median of 23.6 months. As patients with cancer live longer and as SRS is increasingly utilized for treatment of brain metastases, the incidence of these previously rare imaging changes is likely to increase. Clinicians should be aware of these late events, with ARE occurring up to 5.3 years and local failure up to 3.8 years following SRS in our cohort.
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http://dx.doi.org/10.1007/s11060-017-2647-xDOI Listing
January 2018

Stereotactic Radiosurgery and Hypofractionated Radiotherapy for Glioblastoma.

Neurosurgery 2018 Jan;82(1):24-34

Department of Radiation Oncology, Stanford University Cancer Center, Stanford, California.

Glioblastoma is the most common primary brain tumor in adults. Standard therapy depends on patient age and performance status but principally involves surgical resection followed by a 6-wk course of radiation therapy given concurrently with temozolomide chemotherapy. Despite such treatment, prognosis remains poor, with a median survival of 16 mo. Challenges in achieving local control, maintaining quality of life, and limiting toxicity plague treatment strategies for this disease. Radiotherapy dose intensification through hypofractionation and stereotactic radiosurgery is a promising strategy that has been explored to meet these challenges. We review the use of hypofractionated radiotherapy and stereotactic radiosurgery for patients with newly diagnosed and recurrent glioblastoma.
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http://dx.doi.org/10.1093/neuros/nyx115DOI Listing
January 2018

Phase 1/2 Trial of 5-Fraction Stereotactic Radiosurgery With 5-mm Margins With Concurrent and Adjuvant Temozolomide in Newly Diagnosed Supratentorial Glioblastoma: Health-Related Quality of Life Results.

Int J Radiat Oncol Biol Phys 2017 05 7;98(1):123-130. Epub 2017 Feb 7.

Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California. Electronic address:

Purpose: We report a longitudinal assessment of health-related quality of life (HRQOL) in patients with glioblastoma (GBM) treated on a prospective dose escalation trial of 5-fraction stereotactic radiosurgery (25-40 Gy in 5 fractions) with concurrent and adjuvant temozolomide.

Methods: HRQOL was assessed using the European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaire core-30 (QLQ-C30) general, the EORTC quality of life questionnaire-brain cancer specific module (QLQ-BN20), and the M.D. Anderson Symptom Inventory-Brain Tumor (MDASI-BT). Questionnaires were completed at baseline and at every follow-up visit after completion of radiosurgery. Changes from baseline for 9 predefined HRQOL measures (global quality of life, physical functioning, social functioning, emotional functioning, motor dysfunction, communication deficit, fatigue, insomnia, and future uncertainty) were calculated at every time point.

Results: With a median follow-up time of 10.4 months (range, 0.4-52 months), 139 total HRQOL questionnaires were completed by the 30 patients on trial. Compliance with HRQOL assessment was 76% at 12 months. Communication deficit significantly worsened over time, with a decline of 1.7 points per month (P=.008). No significant changes over time were detected in the other 8 scales of our primary analysis, including global quality of life. Although 8 patients (27%) experienced adverse radiation effects (ARE) on this dose escalation trial, it was not associated with a statistically significant decline in any of the primary HRQOL scales. Disease progression was associated with communication deficit, with patients experiencing an average worsening of 13.9 points per month after progression compared with 0.7 points per month before progression (P=.01).

Conclusion: On this 5-fraction dose escalation protocol for newly diagnosed GBM, overall HRQOL remained stable and appears similar to historical controls of 30 fractions of radiation therapy. Tumor recurrence was associated with worsening communication deficit, and ARE did not correlate with a decline in HRQOL.
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http://dx.doi.org/10.1016/j.ijrobp.2017.01.242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6193756PMC
May 2017

Chemoradiation impairs normal developmental cortical thinning in medulloblastoma.

J Neurooncol 2017 Jun 22;133(2):429-434. Epub 2017 May 22.

Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA.

Medulloblastoma patients are treated with surgery, radiation and chemotherapy. Radiation dose to the temporal lobe may be associated with neurocognitive sequelae. Longitudinal changes of temporal lobe cortical thickness may result from neurodevelopmental processes such as synaptic pruning. This study applies longitudinal image analysis to compare developmental change in cortical thickness in medulloblastoma (MB) patients who were treated by combined modality therapy to that of cerebellar juvenile pilocytic astrocytoma (JPA) patients who were treated by surgery alone. We hypothesized that the rates of developmental change in cortical thickness would differ between these two groups. This retrospective cohort study assessed changes in cortical thickness over time between MB and JPA patients. High-resolution magnetic resonance (MR) images of 14 MB and 7 JPA subjects were processed to measure cortical thickness of bilateral temporal lobe substructures. A linear mixed effects model was used to identify differences in substructure longitudinal changes in cortical thickness. The left temporal lobe exhibited overall increased cortical thickness in MB patients relative to JPA patients who showed overall cortical thinning (mean annual cortical thickness change: MB 0.14 mm/year versus JPA -0.018 mm/year across all substructures), particularly in the inferior temporal lobe substructures (p < 0.0001). The cortical thickness change of the right temporal lobe substructures exhibited similar, though attenuated trends (p = 0.002). MB patients exhibit overall increased cortical thickness rather than cortical thinning as seen in JPA patients and as expected in normal cortical development. These observations are possibly due to chemoradiation induced-disruption of normal neuronal mechanisms. Longitudinal image analysis may identify early biomarkers for neurocognitive function with routine imaging.
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http://dx.doi.org/10.1007/s11060-017-2453-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5873287PMC
June 2017

Brain Perfusion and Diffusion Abnormalities in Children Treated for Posterior Fossa Brain Tumors.

J Pediatr 2017 06 7;185:173-180.e3. Epub 2017 Feb 7.

Department of Radiology, Lucile Packard Children's Hospital, Stanford University, Stanford, CA. Electronic address:

Objective: To compare cerebral perfusion and diffusion in survivors of childhood posterior fossa brain tumor with neurologically normal controls and correlate differences with cognitive dysfunction.

Study Design: We analyzed retrospectively arterial spin-labeled cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) in 21 patients with medulloblastoma (MB), 18 patients with pilocytic astrocytoma (PA), and 64 neurologically normal children. We generated ANCOVA models to evaluate treatment effects on the cerebral cortex, thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, nucleus accumbens, and cerebral white matter at time points an average of 5.7 years after original diagnosis. A retrospective review of patient charts identified 12 patients with neurocognitive data and in whom the relationship between IQ and magnetic resonance imaging variables was assessed for each brain structure.

Results: Patients with MB (all treated with surgery, chemotherapy, and radiation) had significantly lower global CBF relative to controls (10%-23% lower, varying by anatomic region, all adjusted P?
Conclusions: The treatment for MB, but not PA, was associated with globally reduced CBF. Treatment in both tumor types was associated with diffusion abnormalities of the mesial temporal lobe structures. Despite significant perfusion abnormalities in patients with MB, diffusion, but not perfusion, correlated with cognitive outcomes.
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http://dx.doi.org/10.1016/j.jpeds.2017.01.019DOI Listing
June 2017

Image-guided stereotactic radiosurgery for treatment of spinal hemangioblastoma.

Neurosurg Focus 2017 Jan;42(1):E12

Departments of 1 Neurosurgery and.

OBJECTIVE Stereotactic radiosurgery (SRS) has been an attractive treatment option for hemangioblastomas, especially for lesions that are surgically inaccessible and in patients with von Hippel-Lindau (VHL) disease and multiple lesions. Although there has been a multitude of studies examining the utility of SRS in intracranial hemangioblastomas, SRS has only recently been used for spinal hemangioblastomas due to technical limitations. The purpose of this study is to provide a long-term evaluation of the effectiveness of image-guided radiosurgery in halting tumor progression and providing symptomatic relief for spinal hemangioblastomas. METHODS Between 2001 and 2011, 46 spinal hemangioblastomas in 28 patients were treated using the CyberKnife image-guided radiosurgery system at the authors' institution. Fourteen of these patients also had VHL disease. The median age at treatment was 43.5 years (range 19-85 years). The mean prescription radiation dose to the tumor periphery was 21.6 Gy (range 15-35 Gy). The median tumor volume was 0.264 cm (range 0.025-70.9 cm). Tumor response was evaluated on serial, contrast-enhanced CT and MR images. Clinical response was evaluated by clinical and imaging evaluation. RESULTS The mean follow-up for the cohort was 54.3 months. Radiographic follow-up was available for 19 patients with 34 tumors; 32 (94.1%) tumors were radiographically stable or displayed signs of regression. Actuarial control rates at 1, 3, and 5 years were 96.1%, 92.3%, and 92.3%, respectively. Clinical evaluation on follow-up was available for 13 patients with 16 tumors; 13 (81.2%) tumors in 10 patients had symptomatic improvement. No patient developed any complications related to radiosurgery. CONCLUSIONS Image-guided SRS is safe and effective for the primary treatment of spinal hemangioblastomas and is an attractive alternative to resection, especially for those with VHL disease.
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http://dx.doi.org/10.3171/2016.10.FOCUS16361DOI Listing
January 2017

Consensus guidelines for postoperative stereotactic body radiation therapy for spinal metastases: results of an international survey.

J Neurosurg Spine 2017 Mar 11;26(3):299-306. Epub 2016 Nov 11.

Department of Radiation Oncology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada.

OBJECTIVE Although postoperative stereotactic body radiation therapy (SBRT) for spinal metastases is increasingly performed, few guidelines exist for this application. The purpose of this study is to develop consensus guidelines to promote safe and effective treatment for patients with spinal metastases. METHODS Fifteen radiation oncologists and 5 neurosurgeons, representing 19 centers in 4 countries and having a collective experience of more than 1300 postoperative spine SBRT cases, completed a 19-question survey about postoperative spine SBRT practice. Responses were defined as follows: 1) consensus: selected by ≥ 75% of respondents; 2) predominant: selected by 50% of respondents or more; and 3) controversial: no single response selected by a majority of respondents. RESULTS Consensus treatment indications included: radioresistant primary, 1-2 levels of adjacent disease, and previous radiation therapy. Contraindications included: involvement of more than 3 contiguous vertebral bodies, ASIA Grade A status (complete spinal cord injury without preservation of motor or sensory function), and postoperative Bilsky Grade 3 residual (cord compression without any CSF around the cord). For treatment planning, co-registration of the preoperative MRI and postoperative T1-weighted MRI (with or without gadolinium) and delineation of the cord on the T2-weighted MRI (and/or CT myelogram in cases of significant hardware artifact) were predominant. Consensus GTV (gross tumor volume) was the postoperative residual tumor based on MRI. Predominant CTV (clinical tumor volume) practice was to include the postoperative bed defined as the entire extent of preoperative tumor, the relevant anatomical compartment and any residual disease. Consensus was achieved with respect to not including the surgical hardware and incision in the CTV. PTV (planning tumor volume) expansion was controversial, ranging from 0 to 2 mm. The spinal cord avoidance structure was predominantly the true cord. Circumferential treatment of the epidural space and margin for paraspinal extension was controversial. Prescription doses and spinal cord tolerances based on clinical scenario, neurological compromise, and prior overlapping treatments were controversial, but reasonable ranges are presented. Fifty percent of those surveyed practiced an integrated boost to areas of residual tumor and density override for hardware within the beam path. Acceptable PTV coverage was controversial, but consensus was achieved with respect to compromising coverage to meet cord constraint and fractionation to improve coverage while meeting cord constraint. CONCLUSIONS The consensus by spinal radiosurgery experts suggests that postoperative SBRT is indicated for radioresistant primary lesions, disease confined to 1-2 vertebral levels, and/or prior overlapping radiotherapy. The GTV is the postoperative residual tumor, and the CTV is the postoperative bed defined as the entire extent of preoperative tumor and anatomical compartment plus residual disease. Hardware and scar do not need to be included in CTV. While predominant agreement was reached about treatment planning and definition of organs at risk, future investigation will be critical in better understanding areas of controversy, including whether circumferential treatment of the epidural space is necessary, management of paraspinal extension, and the optimal dose fractionation schedules.
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http://dx.doi.org/10.3171/2016.8.SPINE16121DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5551391PMC
March 2017