Publications by authors named "Asal Rahimi"

29 Publications

  • Page 1 of 1

Future Directions in the Use of SAbR for the Treatment of Oligometastatic Cancers.

Semin Radiat Oncol 2021 Jul;31(3):253-262

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX; Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI. Electronic address:

The role of local therapy as a sole therapy or part of a combined approach in treating metastatic cancer continues to evolve. The most obvious requirements for prudent implementation of local therapies like stereotactic ablative radiotherapy (SAbR) to become mainstream in treating oligometastases are (1) Clear guidance as to what particular patients might benefit, and (2) Confirmation of improvements in outcome after such treatments via clinical trials. These future directional requirements are non-negotiable. However, innovation and research offer many more opportunities to understand and improve therapy. Identifying candidates and personalizing their therapy can be afforded via proteomic, genomic and epigenomic characterization techniques. Such molecular profiling along with liquid biopsy opportunities will both help select best therapies and facilitate ongoing monitoring of response. Technologies both to find targets and help deliver less-toxic therapy continue to improve and will be available in the marketplace. These technologies include molecular-based imaging (eg, PET-PSMA), FLASH ultra-high dose rate platforms, Grid therapy, PULSAR adaptive dosing, and MRI/PET guided linear accelerators. Importantly, a treatment approach beyond oligometastastic could evolve including a rationale for using SAbR in the oligoprogressive, oligononresponsive, oligobulky and oligolethal settings as well as expansion beyond oligo- toward even plurimetastastic disease. In any case, lessons learned and experiences required by the implementation of using SAbR in oligometastatic cancer will be revisited.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.semradonc.2021.03.004DOI Listing
July 2021

Survival of women diagnosed with breast cancer and who have survived a previous cancer.

Breast Cancer Res Treat 2021 Jun 23;187(3):853-865. Epub 2021 Feb 23.

Department of Population & Data Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9066, USA.

Purpose: Many women diagnosed with breast cancer have survived previous cancer; yet little is known about the impact of previous cancer on overall and cancer-specific survival.

Methods: This population-based cohort study using SEER-Medicare data included women (age ≥ 66 years) diagnosed with breast cancer between 2005 and 2015. Separately by breast cancer stage, we estimated effect of previous cancer on overall survival using Cox regression and on cause-specific survival using competing risk regression; all survival analyses adjusted for covariates.

Results: Of 138,576 women diagnosed with breast cancer, 8% had a previous cancer of another organ site, most commonly colorectal or uterine cancer or melanoma. Many of these women (46.3%) were diagnosed within 5 years of breast cancer. For all breast cancer stages except IV wherein there was no difference, women with vs. without previous cancer had worse overall survival. This survival disadvantage was driven by deaths due to the previous cancer and other causes. In contrast, women with previous cancer generally had favorable breast-cancer-specific survival, although this varied by stage. Overall survival varied by previous cancer type, timing, and stage; previous lung cancer, cancer diagnosed within 1 year of incident breast cancer, and previous cancer at a distant stage were associated with the worst survival. In contrast, women with a previous melanoma had equivalent overall survival to women without previous cancer.

Conclusion: We observed variable impact of previous cancer on overall and breast-cancer-specific survival depending on breast cancer stage at diagnosis and the type, timing, and stage of previous cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10549-021-06122-wDOI Listing
June 2021

Cosmetic Outcomes of a Phase 1 Dose Escalation Study of 5-Fraction Stereotactic Partial Breast Irradiation for Early Stage Breast Cancer.

Int J Radiat Oncol Biol Phys 2021 Jul 18;110(3):772-782. Epub 2021 Jan 18.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas.

Purpose: Our purpose was to evaluate cosmetic changes after 5-fraction adjuvant stereotactic partial breast irradiation (S-PBI).

Methods And Materials: Seventy-five women with in situ or invasive breast cancer stage 0, I, or II, with tumor size ≤3 cm, were enrolled after lumpectomy in a phase 1 dose escalation trial of S-PBI into cohorts receiving 30, 32.5, 35, 37.5, or 40 Gy in 5 fractions. Before S-PBI, 3 to 4 gold fiducial markers were placed in the lumpectomy cavity for tracking with the Synchrony respiratory tracking system. S-PBI was delivered with a CyberKnife robotic radiosurgery system. Patients and physicians evaluated global cosmesis using the Harvard Breast Cosmesis Scale. Eight independent panelists evaluated digital photography for global cosmesis and 10 subdomains at baseline and follow-up. McNemar tests were used to evaluate change in cosmesis, graded as excellent/good or fair/poor, from baseline to year 3. Wilcoxon signed rank tests were used to evaluate change in subdomains. Cohen's kappa (κ) statistic was used to estimate interobserver agreement (IOA) between raters, and Fleiss' κ was used to estimate IOA between panelists.

Results: Median cosmetic follow-up was 5, 5, 5, 4, and 3 years for the 30, 32.5, 35, 37.5, and 40 Gy cohorts. Most patients reported excellent/good cosmesis at both baseline (86.3%) and year 3 (89.8%). No dose cohort had significantly worsened cosmesis by year 3 on McNemar analysis. No cosmetic subdomain had significant worsening by year 3. IOA was fair for patient-physician (κ = 0.300, P < .001), patient-panel (κ = 0.295, P < .001), physician-panel (κ = 0.256, P < .001), and individual panelists (Fleiss κ = 0.327, P < .001).

Conclusions: Dose escalation of S-PBI from 30 to 40 Gy in 5 fractions for early stage breast cancer was not associated with a detectable change in cosmesis by year 3. S-PBI is a promising modality for treatment of early stage breast cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijrobp.2021.01.015DOI Listing
July 2021

Curing Metastatic Disease with Radiation Therapy: Myth or Reality?-Arguing for Reality.

Int J Radiat Oncol Biol Phys 2020 07;107(3):429-432

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas; Harold C. Simmons Comprehensive Cancer Center, Dallas, Texas. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijrobp.2020.03.009DOI Listing
July 2020

Risk Factors for Fat Necrosis After Stereotactic Partial Breast Irradiation for Early-Stage Breast Cancer in a Phase 1 Clinical Trial.

Int J Radiat Oncol Biol Phys 2020 11 26;108(3):697-706. Epub 2020 May 26.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas.

Purpose: This study reports predictive dosimetric and physiologic factors for fat necrosis after stereotactic-partial breast irradiation (S-PBI).

Methods And Materials: Seventy-five patients with ductal carcinoma-in situ or invasive nonlobular epithelial histologies stage 0, I, or II, with tumor size <3 cm were enrolled in a dose-escalation, phase I S-PBI trial between January 2011 and July 2015. Fat necrosis was evaluated clinically at each follow-up. Treatment data were extracted from the Multiplan Treatment Planning System (Cyberknife, Accuray). Univariate and stepwise logistic regression analyses were conducted to identify factors associated with palpable fat necrosis.

Results: With a median follow-up of 61 months (range: 4.3-99.5 months), 11 patients experienced palpable fat necrosis, 5 cases of which were painful. The median time to development of fat necrosis was 12.7 months (range, 3-42 months). On univariate analyses, higher V32.5-47.5 Gy (P < .05) and larger breast volume (P < .01) were predictive of any fat necrosis; higher V35-50 Gy (P < .05), receiving 2 treatments on consecutive days (P = .02), and higher Dmax (P = .01) were predictive of painful fat necrosis. On multivariate analyses, breast volume larger than 1063 cm remained a predictive factor for any fat necrosis; receiving 2 treatments on consecutive days and higher V45 Gy were predictive of painful fat necrosis. Breast laterality, planning target volume (PTV), race, body mass index, diabetic status, and tobacco or drug use were not significantly associated with fat necrosis on univariate analysis.

Conclusions: Early-stage breast cancer patients treated with breast conserving surgery and S-PBI in our study had a fat necrosis rate comparable to other accelerated partial breast irradiation modalities, but S-PBI is less invasive. To reduce risk of painful fat necrosis, we recommend not delivering fractions on consecutive days; limiting V42.5 < 50 cm, V45 < 20 cm, V47.5 < 1 cm, Dmax ≤ 48 Gy and PTV < 100 cm when feasible; and counseling patients about the increased risk for fat necrosis when constraints are not met and for those with breast volume >1000 cm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijrobp.2020.05.025DOI Listing
November 2020

Phase II trial of hippocampal-sparing whole brain irradiation with simultaneous integrated boost for metastatic cancer.

Neuro Oncol 2020 12;22(12):1831-1839

Department of Radiation Oncology, Fairfax, Virginia.

Background: Advanced radiotherapeutic treatment techniques limit the cognitive morbidity associated with whole-brain radiotherapy (WBRT) for brain metastasis through avoidance of hippocampal structures. However, achieving durable intracranial control remains challenging.

Methods: We conducted a single-institution single-arm phase II trial of hippocampal-sparing whole brain irradiation with simultaneous integrated boost (HSIB-WBRT) to metastatic deposits in adult patients with brain metastasis. Radiation therapy consisted of intensity-modulated radiation therapy delivering 20 Gy in 10 fractions over 2-2.5 weeks to the whole brain with a simultaneous integrated boost of 40 Gy in 10 fractions to metastatic lesions. Hippocampal regions were limited to 16 Gy. Cognitive performance and cancer outcomes were evaluated.

Results: A total of 50 patients, median age 60 years (interquartile range, 54-65), were enrolled. Median progression-free survival was 2.9 months (95% CI: 1.5-4.0) and overall survival was 9 months. As expected, poor survival and end-of-life considerations resulted in a high exclusion rate from cognitive testing. Nevertheless, mean decline in Hopkins Verbal Learning Test-Revised delayed recall (HVLT-R DR) at 3 months after HSIB-WBRT was only 10.6% (95% CI: -36.5‒15.3%). Cumulative incidence of local and intracranial failure with death as a competing risk was 8.8% (95% CI: 2.7‒19.6%) and 21.3% (95% CI: 10.7‒34.2%) at 1 year, respectively. Three grade 3 toxicities consisting of nausea, vomiting, and necrosis or headache were observed in 3 patients. Scores on the Multidimensional Fatigue Inventory 20 remained stable for evaluable patients at 3 months.

Conclusions: HVLT-R DR after HSIB-WBRT was significantly improved compared with historical outcomes in patients treated with traditional WBRT, while achieving intracranial control similar to patients treated with WBRT plus stereotactic radiosurgery (SRS). This technique can be considered in select patients with multiple brain metastases who cannot otherwise receive SRS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/neuonc/noaa092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7746928PMC
December 2020

Improving the Time to Activation of New Clinical Trials at a National Cancer Institute-Designated Comprehensive Cancer Center.

JCO Oncol Pract 2020 04 16;16(4):e324-e332. Epub 2020 Jan 16.

Harold C. Simmons Comprehensive Cancer Center, The University of Texas Southwestern Medical Center, Dallas, TX.

Purpose: The time it takes a performing site to activate a clinical trial can directly affect the ability to provide innovative and state-of-the-art care to patients. We sought to understand the process of activating an oncology clinical trial at a matrix National Cancer Institute-designated comprehensive cancer center.

Methods: A multidisciplinary team of stakeholders within the cancer center, university, and affiliate hospitals held a retreat to map out the process of activating a clinical trial. We applied classical quality improvement and Six Sigma methodology to determine bottlenecks and non-value-added time in activating a clinical trial. During this process, attention was paid to time to pass through each step, and perceived barriers and bottlenecks were identified through group discussions.

Results: The process map identified 66 steps with 12 decision points to activate a new clinical trial. The following two steps were instituted first: allow parallel scientific committee and institutional review board (IRB) review and allow the clinical research coordination committee, a group that determines university interest and feasibility, to review protocols independent of the IRB and scientific committee approval. The clinical research coordination committee continues to track the activation time, and this framework is used to identify additional improvement steps.

Conclusion: By applying quality improvement methodologies and Six Sigma principles, we were able to identify redundancies in the process to activate a clinical trial. This allowed us to redesign the process of activating a clinical trial at a matrix comprehensive cancer center. More importantly, the process map provides a framework to maintain these gains and implement additional changes and serves as an example to deploy across the campus and at other similar institutions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1200/OP.19.00325DOI Listing
April 2020

A Reliable Multi-classifier Multi-objective Model for Predicting Recurrence in Triple Negative Breast Cancer

Annu Int Conf IEEE Eng Med Biol Soc 2019 Jul;2019:2182-2185

Recurrence is a significant prognostic factor in patients with triple negative breast cancer, and the ability to accurately predict it is essential for treatment optimization. Machine learning is a preferred strategy for recurrence prediction. Most current predictive models are built based on single classifier and trained through a single objective. However, since many classifiers are available, selecting an optimal model is challenging. On the other hand, a single objective may not be a good measure to guide model training. We proposed a new multi-classifier multi-objective (MCMO) recurrence predictive model. Specifically, new similarity-based sensitivity and specificity were defined and considered as the two objective functions simultaneously during training. Also the evidential reasoning (ER) approach was used for fusing the output of each classifier to obtain more reliable outcome. Using the proposed MCMO model, we achieved a predictive area under the receiver operating characteristic curve (AUC) of 0.9 with balanced sensitivity and specificity. Furthermore, MCMO outperformed all the individual classifiers, and yielded more reliable results than other commonly used optimization and fusion methods.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/EMBC.2019.8857030DOI Listing
July 2019

Novel hyaluronan formulation for preventing acute skin reactions in breast during radiotherapy: a randomized clinical trial.

Support Care Cancer 2020 Mar 4;28(3):1481-1489. Epub 2019 Jul 4.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, 2280 Inwood Rd, Dallas, TX, 75390, USA.

Purpose: We conducted a randomized, double-blind, vehicle-controlled clinical trial to investigate the use of a new proprietary hyaluronan (HA) formulation for the prevention of acute skin toxicity in breast cancer patients undergoing radiotherapy (RT).

Methods: Thirty women with breast cancer undergoing whole breast RT were enrolled. Each patient was randomly assigned to HA formulation (study cream, S) on the medial or lateral half of the irradiated breast and the control cream (placebo, P) on the other half. The primary endpoint was physician's evaluation of skin symptoms at week 5 during RT and week 2 post-RT. We also collected patients' independent assessment of skin after RT, patient's product preference, and an independent physician panel assessment of skin reactions based on photographs.

Results: Twenty-eight patients were evaluable. On physician's evaluation, there was no significant difference in radiation dermatitis between S and P and no overall preference to either cream at week 5 during or week 2 post-RT. More patients preferred S in evaluating skin appearance and skin reactions, but this did not reach statistical significance. Univariate analysis showed that physicians had an overall preference to the S cream at week 2 post-RT in patients with larger breasts. On the independent panel assessment, 3 reviewers saw no significant difference in radiation toxicity, whereas one reviewer reported better skin outcome with S cream at week 5.

Conclusions: We found a nonstatistically significant patient preference but overall no significant radioprotective effects for this HA formulation compared with placebo except in patients with larger breasts.

Trial Registration: The study was registered at www.clinicaltrials.gov (NCT02165605).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00520-019-04957-0DOI Listing
March 2020

Deep-learning based surface region selection for deep inspiration breath hold (DIBH) monitoring in left breast cancer radiotherapy.

Phys Med Biol 2018 Dec 12;63(24):245013. Epub 2018 Dec 12.

School of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong 510515, People's Republic of China. Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, United States of America.

Deep inspiration breath hold (DIBH) with surface supervising is a common technique for cardiac dose reduction in left breast cancer radiotherapy. Surface supervision accuracy relies on the characteristics of surface region. In this study, a convolutional neural network (CNN) based automatic region-of-interest (ROI) selection method was proposed to select an optimal surface ROI for DIBH surface monitoring. The curvature entropy and the normal of each vertex on the breast cancer patient surface were calculated and formed as representative maps for ROI selection learning. 900 ROIs were randomly extracted from each patient's surface representative map, and the corresponding rigid ROI registration errors (REs) were calculated. The VGG-16 (a 16-layer network structure developed by Visual Geometry Group(VGG) from University of Oxford) pre-trained on a large natural image database ImageNet were fine-tuned using 27 thousand extracted ROIs and the corresponding REs from thirty patients. The RE prediction accuracy of the trained model was validated on additional ten patients. Satisfactory RE predictive accuracies were achieved with the root mean square error (RMSE)/mean absolute error (MAE) smaller than 1 mm/0.7 mm in translations and 0.45°/0.35° in rotations, respectively. The REs of the model selected ROIs on ten testing cases is close to the minimal predicted RE with mean RE differences  <1 mm and  <0.5° for translation and rotation, respectively. The proposed RE predictive model can be utilized for selecting a quasi-optimal ROI in left breast cancer DIBH radiotherapy (DIBH-RT).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/1361-6560/aaf0d6DOI Listing
December 2018

Electronic Medical Record-Based Radiation Oncology Toxicity Recording Instrument Aids Benchmarking and Quality Improvement in the Clinic.

J Oncol Pract 2018 03 13;14(3):e186-e193. Epub 2018 Feb 13.

University of Texas Southwestern Medical Center, Dallas, TX.

Purpose: The on-treatment visit (OTV) for radiation oncology is essential for patient management. Radiation toxicities recorded during the OTV may be inconsistent because of the use of free text and the lack of treatment site-specific templates. We developed a radiation oncology toxicity recording instrument (ROTOX) in a health system electronic medical record (EMR). Our aims were to assess improvement in documentation of toxicities and to develop clinic toxicity benchmarks.

Methods: A ROTOX that was based on National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0) with flow-sheet functionality was developed in the EMR. Improvement in documentation was assessed at various time intervals. High-grade toxicities (ie, grade ≥ 3 by CTCAE) by site were audited to develop benchmarks and to track nursing and physician actions taken in response to these.

Results: A random sample of OTV notes from each clinic physician before ROTOX implementation was reviewed and assigned a numerical document quality score (DQS) that was based on completeness and comprehensiveness of toxicity grading. The mean DQS improved from an initial level of 41% to 99% (of the maximum possible DQS) when resampled at 6 months post-ROTOX. This high-level DQS was maintained 3 years after ROTOX implementation at 96% of the maximum. For months 7 to 9 after implementation (during a 3-month period), toxicity grading was recorded in 4,443 OTVs for 698 unique patients; 107 episodes of high-grade toxicity were identified during this period, and toxicity-specific intervention was documented in 95%.

Conclusion: An EMR-based ROTOX enables consistent recording of treatment toxicity. In a uniform sample of patients, local population toxicity benchmarks can be developed, and clinic response can be tracked.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1200/JOP.2017.025163DOI Listing
March 2018

Prototype volumetric ultrasound tomography image guidance system for prone stereotactic partial breast irradiation: proof-of-concept.

Phys Med Biol 2018 03 1;63(5):055004. Epub 2018 Mar 1.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America. Tsuicheng Chiu and David Parsons contributed equally to this study.

Accurate dose delivery in stereotactic partial breast irradiation (S-PBI) is challenging because of the target position uncertainty caused by breast deformation, the target volume changes caused by lumpectomy cavity shrinkage, and the target delineation uncertainty on simulation computed tomography (CT) images caused by poor soft tissue contrast. We have developed a volumetric ultrasound tomography (UST) image guidance system for prone position S-PBI. The system is composed of a novel 3D printed rotation water tank, a patient-specific resin breast immobilization cup, and a 1D array ultrasound transducer. Coronal 2D US images were acquired in 5° increments over a 360° range, and planes were acquired every 2 mm in elevation. A super-compounding technique was used to reconstruct the image volume. The image quality of UST was evaluated with a BB-1 breast phantom and BioZorb surgical marker, and the results revealed that UST offered better soft tissue contrast than CT and similar image quality to MR. In the evaluated plane, the size and location of five embedded objects were measured and compared to MR, which is considered as the ground truth. Objects' diameters and the distances between objects in UST differ by approximately 1 to 2 mm from those in MR, which showed that UST offers the image quality required for S-PBI. In future work we will develop a robotic system that will be ultimately implemented in the clinic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/1361-6560/aaad1fDOI Listing
March 2018

Review of breast screening: Toward clinical realization of microwave imaging.

Med Phys 2017 Dec 1;44(12):e446-e458. Epub 2017 Nov 1.

Department of Electrical Engineering, University of Texas at Dallas, Dallas, TX, USA.

Microwave imaging (MI) technology has come a long way to introduce a noninvasive, inexpensive, fast, convenient, and safe screening tool for clinical breast monitoring. However, there is a niche between the existing understanding of MI by engineers versus clinicians. Our manuscript targets that niche and highlights the state of the art in MI technology compared to the existing breast cancer detection modalities (mammography, ultrasound, molecular imaging, and magnetic resonance). The significance of our review article is in consolidation of up-to-date breast clinician views with the practical needs and engineering challenges of a novel breast screening modality. We summarize breast tissue abnormalities and highlight the benefits as well as potential drawbacks of the MI as a cancer detection methodology. Our goal is to present an article that MI researchers as well as practitioners in the field can use to assess the viability of the MI technology as a competing or complementary modality to the existing means of breast cancer screening.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mp.12611DOI Listing
December 2017

Primary synovial chondromatosis of the subtalar joint: case report and review of the literature.

Skeletal Radiol 2018 Mar 20;47(3):391-396. Epub 2017 Sep 20.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, 5801 Forest Park Road, Dallas, TX, 75390-9183, USA.

Primary synovial chondromatosis is a rare benign condition of uncertain etiology manifested by synovial proliferation. In the radiology literature, there is only 1 prior case report of primary synovial chondromatosis involving the subtalar joint with only partial description of the imaging appearance. We present a 28-year-old female with primary synovial chondromatosis of the subtalar joint and conduct a literature review of the imaging features of primary synovial chondromatosis presenting in the feet.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00256-017-2775-6DOI Listing
March 2018

Comprehensive target geometric errors and margin assessment in stereotactic partial breast irradiation.

Radiat Oncol 2017 Sep 11;12(1):151. Epub 2017 Sep 11.

Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.

Background: Recently developed stereotactic partial breast irradiation (S-PBI) allows delivery of a high biologically potent dose to the target while sparing adjacent critical organs and normal tissue. With S-PBI tumoricidal doses, accurate and precise dose delivery is critical to achieve high treatment quality. This study is to investigate both rigid and non-rigid components of target geometric error and their corresponding margins in S-PBI and identify correlated clinical factors.

Methods: Forty-three early-stage breast cancer patients with implanted gold fiducial markers were enrolled in the study. Fiducial positions recorded on the orthogonal kV images on a Cyberknife system during treatment were used to estimate intra-fraction errors and composite errors (including intra-fraction errors and residual errors after patient setup). Both rigid and non-rigid components of intra-fraction and composite errors were analyzed and used to estimate rigid and non-rigid margins, respectively. Univariate and multivariate linear regressions were conducted to evaluate correlations between clinical factors and errors.

Results: For the study group, the intra-fraction rigid and non-rigid errors are 2.0 ± 0.6 mm and 0.3 ± 0.2 mm, respectively. The composite rigid and non-rigid errors are 2.3 ± 0.5 mm and 1.3 ± 0.8 mm, respectively. The rigid margins in the left-right, anterior-posterior, and superior-inferior directions are estimated as 2.1, 2.4, and 2.3 mm, respectively. The estimated non-rigid margin, assumed to be isotropic, is 1.7 mm. The outer breast quadrants are more susceptible to composite errors occurrence than the inner breast quadrants. The target to chest wall distance is the clinical factor correlated with target geometric errors.

Conclusions: This is the first comprehensive analysis of breast target geometric rigid and non-rigid errors in S-PBI. Upon the estimation, the non-rigid margin is comparable to rigid margin, and therefore should be included in planning target volume as it cannot be accounted for by the Cyberknife system. Treatment margins selection also need to consider the impact of relevant clinical factor.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13014-017-0889-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5594509PMC
September 2017

In Reply to Gerber et al.

Int J Radiat Oncol Biol Phys 2017 10;99(2):499-500

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijrobp.2017.05.043DOI Listing
October 2017

Deep inspiration breathhold for left-sided breast cancer patients with unfavorable cardiac anatomy requiring internal mammary nodal irradiation.

Pract Radiat Oncol 2017 Nov - Dec;7(6):e361-e367. Epub 2017 Apr 13.

Department of Radiation Oncology, University of Texas-Southwestern, Moncrief Radiation Oncology Center, Dallas, Texas. Electronic address:

Purpose: The purpose of this study was to evaluate the utility of moderate deep inspiration breathhold (mDIBH) in reducing heart exposure in left breast cancer patients who have unfavorable cardiac anatomy and need internal mammary lymph node (IMLN) radiation therapy (RT).

Methods And Materials: We used maximum heart distance (MHD), defined as the maximum distance of the heart within the treatment field, >1 cm as a surrogate for unfavorable cardiac anatomy. Twenty-two left breast cancer patients with unfavorable cardiac anatomy requiring IMLN-RT underwent free-breathing (FB) and mDIBH computed tomography simulation and planning. Three-dimensional partially wide tangents (3D-PWTs) and intensity modulated RT plans were generated. Dose-volume histograms were used to compare heart and lung dosimetric parameters. Duration of treatment delivery was recorded for all fractions.

Results: MHD decreased significantly in mDIBH scans. mDIBH significantly reduced mean heart dose (222.7 vs 578.4 cGy; P < .0001) and percentage of left lung receiving doses ≥20 Gy (V20; 31.93 vs 38.41%; P = .0006) in both 3D-PWT and intensity modulated RT plans. The change in MHD after breathhold reliably predicted mean heart dose reduction after mDIBH. Radiation was effectively delivered in 11.31 ± 3.40 minutes with an average of 10.06 ± 2.74 breathholds per fraction.

Conclusions: mDIBH is efficient and can effectively decrease mean heart dose in patients with unfavorable cardiac anatomy who need IMLN-RT, thus simplifying planning and delivery for them. The reduction in mean heart dose is proportional to the reduction in maximum heart distance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.prro.2017.04.006DOI Listing
July 2018

Carbon Ion Radiotherapy: A Review of Clinical Experiences and Preclinical Research, with an Emphasis on DNA Damage/Repair.

Cancers (Basel) 2017 Jun 9;9(6). Epub 2017 Jun 9.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.

Compared to conventional photon-based external beam radiation (PhXRT), carbon ion radiotherapy (CIRT) has superior dose distribution, higher linear energy transfer (LET), and a higher relative biological effectiveness (RBE). This enhanced RBE is driven by a unique DNA damage signature characterized by clustered lesions that overwhelm the DNA repair capacity of malignant cells. These physical and radiobiological characteristics imbue heavy ions with potent tumoricidal capacity, while having the potential for simultaneously maximally sparing normal tissues. Thus, CIRT could potentially be used to treat some of the most difficult to treat tumors, including those that are hypoxic, radio-resistant, or deep-seated. Clinical data, mostly from Japan and Germany, are promising, with favorable oncologic outcomes and acceptable toxicity. In this manuscript, we review the physical and biological rationales for CIRT, with an emphasis on DNA damage and repair, as well as providing a comprehensive overview of the translational and clinical data using CIRT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers9060066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5483885PMC
June 2017

Preliminary Results of a Phase 1 Dose-Escalation Trial for Early-Stage Breast Cancer Using 5-Fraction Stereotactic Body Radiation Therapy for Partial-Breast Irradiation.

Int J Radiat Oncol Biol Phys 2017 05 12;98(1):196-205.e2. Epub 2017 Jan 12.

University of Texas Southwestern Medical Center, Dallas, Texas.

Purpose: To evaluate the tolerability of a dose-escalated 5-fraction stereotactic body radiation therapy for partial-breast irradiation (S-PBI) in treating early-stage breast cancer after partial mastectomy; the primary objective was to escalate dose utilizing a robotic stereotactic radiation system treating the lumpectomy cavity without exceeding the maximum tolerated dose.

Methods And Materials: Eligible patients included those with ductal carcinoma in situ or invasive nonlobular epithelial histologies and stage 0, I, or II, with tumor size <3 cm. Patients and physicians completed baseline and subsequent cosmesis outcome questionnaires. Starting dose was 30 Gy in 5 fractions and was escalated by 2.5 Gy total for each cohort to 40 Gy.

Results: In all, 75 patients were enrolled, with a median age of 62 years. Median follow-up for 5 cohorts was 49.9, 42.5, 25.7, 20.3, and 13.5 months, respectively. Only 3 grade 3 toxicities were experienced. There was 1 dose-limiting toxicity in the overall cohort. Ten patients experienced palpable fat necrosis (4 of which were symptomatic). Physicians scored cosmesis as excellent or good in 95.9%, 100%, 96.7%, and 100% at baseline and 6, 12, and 24 months after S-PBI, whereas patients scored the same periods as 86.5%, 97.1%, 95.1%, and 95.3%, respectively. The disagreement rates between MDs and patients during those periods were 9.4%, 2.9%, 1.6%, and 4.7%, respectively. There have been no recurrences or distant metastases.

Conclusion: Dose was escalated to the target dose of 40 Gy in 5 fractions, with the occurrence of only 1 dose-limiting toxicity. Patients felt cosmetic results improved within the first year after surgery and stereotactic body radiation therapy. Our results show minimal toxicity with excellent cosmesis; however, further follow-up is warranted in future studies. This study is the first to show the safety, tolerability, feasibility, and cosmesis results of a 5-fraction dose-escalated S-PBI treatment for early-stage breast cancer in the adjuvant setting.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijrobp.2017.01.020DOI Listing
May 2017

New Techniques for Irradiating Early Stage Breast Cancer: Stereotactic Partial Breast Irradiation.

Semin Radiat Oncol 2017 07 20;27(3):279-288. Epub 2017 Feb 20.

Department of Radiation Oncology, University of Texas Southwestern, Dallas, TX; Department of Neurosurgery, University of Texas Southwestern, Dallas, TX. Electronic address:

Several improvements in breast cancer radiation delivery have been realized using new techniques over the past several decades. As an example, for early stage disease, there has been active investigation of partial breast irradiation (PBI) vs whole breast irradiation. Although still investigational, PBI reduces the treatment volumes, doses to organs at risk, and may improve cosmesis. Over the past 2 decades PBI has been delivered via interstitial brachytherapy, intracavitary brachytherapy, intraoperative radiation therapy, or 3-dimensional external beam radiation therapy. More recently, there has been growing evidence that supports stereotactic body radiation therapy as a safe and effective new treatment for early stage breast cancer. This article describes this new treatment opportunity and reviews the emerging data of stereotactic partial breast irradiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.semradonc.2017.02.007DOI Listing
July 2017

Ablative Therapy: A Reasonable Approach.

Int J Radiat Oncol Biol Phys 2017 03 24;97(3):448-449. Epub 2016 Oct 24.

Department of Radiation Oncology, University of Texas Southwestern, Dallas, Texas; Department of Neurosurgery, University of Texas Southwestern, Dallas, Texas.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijrobp.2016.10.028DOI Listing
March 2017

Genetic Ancestry using Mitochondrial DNA in patients with Triple-negative breast cancer (GAMiT study).

Cancer 2017 Jan 1;123(1):107-113. Epub 2016 Sep 1.

Division of Medical Oncology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.

Background: Triple-negative breast cancer (TNBC) lacks estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2)/neu receptors, and is aggressive and therapeutically challenging. Genetic ancestry testing is an emerging medical field. Mitochondrial DNA (mtDNA), which is distinct from nuclear DNA, is maternally inherited and allows for origin determination. Patients with TNBC tend to be younger and are more likely to be African American, making this an ideal disease for mtDNA exploration. To the authors' knowledge, the current study is the first to perform mtDNA for self-described African American, White, and Hispanic patients with TNBC to identify mtDNA patterns.

Methods: Patients with TNBC who were at any stage of therapy/survivorship were included. Self-reported ethnicity was confirmed at the time of the prospective buccal swab. Haplogroup prediction was performed on sequencing of hypervariable region 1. Using sequence similarity scores and lineage databases, sequence patterns were determined. Data regarding presentation and treatment, tumor features, and outcomes was collected.

Results: A total of 92 patients were included: 31 self-described African American, 31 White, and 30 Hispanic individuals. Hispanic patients were found to have the largest tumor size (4.5 cm; P = .01) and youngest age (41 years; P<.0001). Eight patients were BRCA1/2 mutation carriers. There were no differences noted among groups with regard to surgery, lymph node metastases, or survival. Analysis revealed Nigerian, Cameroon, or Sierra Leone ancestry and haplogroups A, U, H, or B to be the most common mtDNA patterns. Twelve discordances (13%) between mtDNA analysis and self-described ethnicity were identified among the 92 patients. The highest discordance (26%; 8 patients) was noted in self-described Hispanic patients: 3 had Nigerian ancestry, and 1 individual demonstrated haplogroup K mtDNA (Ashkenazi Jewish ancestry).

Conclusions: Discordance between self-reported ethnicity and mtDNA analysis was identified in 13% of patients with TNBC. The identification of mtDNA patterns with a predisposition toward TNBC may allow for risk stratification. Cancer 2017;107-113. © 2016 American Cancer Society.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cncr.30267DOI Listing
January 2017

Ultrasound-Guided Placement of Gold Fiducial Markers for Stereotactic Partial-Breast Irradiation.

AJR Am J Roentgenol 2016 Sep 9;207(3):685-8. Epub 2016 Aug 9.

1 Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8896.

Objective: A novel technique of placing gold fiducial markers in the breast using ultrasound guidance was developed and performed in 51 of 55 consecutive postlumpectomy patients enrolled in a phase I dose escalation trial of accelerated partial-breast irradiation (APBI) using robotic-based stereotactic body radiation therapy (SBRT).

Conclusion: All 51 postoperative patients underwent successful fiducial placement without complications. Our technique of placing gold fiducial markers in proximity to the seroma cavity is considered safe and effective for breast cancer patients being treated with APBI using robotic-based SBRT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2214/AJR.15.14771DOI Listing
September 2016

Absence of physiologic breast response to pregnancy and lactation after radiation therapy.

Pract Radiat Oncol 2016 Mar-Apr;6(2):e25-6. Epub 2015 Nov 6.

Moncrief Radiation Oncology Center, University of Texas - Southwestern, Dallas, Texas. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.prro.2015.09.010DOI Listing
January 2017

Radiation recall precipitated by iodinated nonionic contrast.

Pract Radiat Oncol 2015 Jul-Aug;5(4):263-6. Epub 2014 Dec 18.

Department of Radiation Oncology, University of Texas Southwestern, Dallas, Texas. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.prro.2014.11.002DOI Listing
April 2016

Radiation practice patterns among United States radiation oncologists for postmastectomy breast reconstruction and oncoplastic breast reduction.

Pract Radiat Oncol 2014 Nov-Dec;4(6):466-71. Epub 2014 Jun 2.

Department of Radiation Oncology, University of Texas Southwestern Medical Center, Moncrief Radiation Oncology Center, Dallas, Texas.

Background: For patients requiring radiation therapy following mastectomy or breast reconstruction, there often exist much heterogeneity among practitioners with respect to radiation technique.

Methods And Materials: A 14-question survey was sent nationwide to 1000 active email addresses from the American Society for Radiation Oncology member directory; 271 radiation oncologists completed the survey.

Results: A total of 75.2% of respondents indicate that they do not routinely deflate the ipsilateral tissue expander (TE) prior to radiation, while 11.5% do routinely deflate (P ≤ .01); 52.2% indicate that they typically use bolus when treating their patients with TEs following mastectomy, 36.7% do not, and 11.1% on a case by case basis (P ≤ .01). Of respondents indicating bolus utilization, 32.8% use a bolus of 0.5 cm every other day; 31.4% indicate a bolus of 0.5 cm every day until tolerated; 20.4% use a bolus of 1 cm every other day; 5.8% indicate a bolus of 1 cm every day until tolerated; and 9.5% indicate a customized bolus approach (P ≤ .01). A total of 22.9% of respondents deliver boost to all patients with TE while 42.9% deliver boost only to select patients, and 33.5% indicate no utilization of boost (P ≤ .01). A total of 33.1% indicate that collaborating surgeons routinely place clips at the lumpectomy cavity at the time of breast reduction or complex tissue rearrangement, while 38.3% indicate that clips are occasionally placed, and 28.6% stated clips are not routinely placed (P = .15); 38.7% of respondents routinely deliver a boost for patients undergoing breast reduction only if clips have been placed in the tumor cavity, while 34.6% indicate that a boost is used regardless of clip placement.

Conclusions: Radiation treatments with tissue expanders have become common practice, but details of radiation treatment vary widely. Radiation oncologist and breast surgeons should continue to work to optimize radiation techniques and allow proper localization for radiation boost.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.prro.2014.04.002DOI Listing
July 2015

Pilot Study of iPad Incorporation Into Graduate Medical Education.

J Grad Med Educ 2013 Mar;5(1):142-4

Background: Increased documentation and charting requirements are challenging for residents, given duty hour limits. Use of mobile electronic devices may help residents complete these tasks efficiently.

Objective: To collect initial data on usage rates, information technology (IT) support requirements, and resident use of iPads during training.

Methods: In this pilot study, we provided 12 residents/fellows from various specialties at the University of Virginia with an iPad with IT support. The system used a virtual private network with access to the institution's electronic health record. Participants were allowed to develop their own methods and systems for personalized iPad use, and after 9 months they provided data on the utility of the iPad. Feedback from the IT team also was obtained.

Results: Average iPad use was 2.1 h/d (range, 0.5-6 h/d). The average self-reported reduction in administrative work due to the iPad was 2.7 h/wk (range, 0-9 h/wk). A total of 75% (9 of 12) of the users would recommend universal adoption among residents and fellows. More than 90% (11 of 12) of users reported the iPad would improve communication for coordination of care. A total of 68% (8 of 12) of users reported that an iPad facilitated their activities as educators of medical students and junior residents. Residents cited slow data entry into the electronic health record and hospital areas lacking Wi-Fi connectivity as potential drawbacks to iPad use. The IT team reported minimal support time for device setup, maintenance, and upgrades, and limited security risks.

Conclusions: The iPad may contribute to increased clinical efficiency, reduced hours spent on administrative tasks, and enhanced educational opportunities for residents, with minimal IT support.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4300/JGME-D-12-00007.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3613300PMC
March 2013

p16, Cyclin D1, and HIF-1α Predict Outcomes of Patients with Oropharyngeal Squamous Cell Carcinoma Treated with Definitive Intensity-Modulated Radiation Therapy.

Int J Otolaryngol 2012 24;2012:685951. Epub 2012 Jul 24.

Department of Radiation Oncology, University of Texas Southwestern, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.

We evaluated a panel of 8 immunohistochemical biomarkers as predictors of clinical response to definitive intensity-modulated radiotherapy in patients with oropharyngeal squamous cell carcinoma (OPSCC). 106 patients with OPSCC were treated to a total dose of 66-70 Gy and retrospectively analyzed for locoregional control (LRC), disease-free survival (DFS), and overall survival (OS). All tumors had p16 immunohistochemical staining, and 101 tumors also had epidermal growth factor receptor (EGFR) staining. 53% of the patients had sufficient archived pathologic specimens for incorporation into a tissue microarray for immunohistochemical analysis for cyclophilin B, cyclin D1, p21, hypoxia-inducible factor-1α (HIF-1α), carbonic anhydrase, and major vault protein. Median followup was 27.2 months. 66% of the tumors were p16 positive, and 34% were p16 negative. On univariate analysis, the following correlations were statistically significant: p16 positive staining with higher LRC (P = 0.005) and longer DFS (P < 0.001); cyclin D1 positive staining with lower LRC (P = 0.033) and shorter DFS (P = 0.002); HIF-1α positive staining with shorter DFS (P = 0.039). On multivariate analysis, p16 was the only significant independent predictor of DFS (P = 0.023). After immunohistochemical examination of a panel of 8 biomarkers, our study could only verify p16 as an independent prognostic factor in OPSCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2012/685951DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3409529PMC
August 2012

p16 not a prognostic marker for hypopharyngeal squamous cell carcinoma.

Arch Otolaryngol Head Neck Surg 2012 Jun;138(6):556-61

Departments of Radiation Oncology, University of Virginia, Charlottesville, VA 22908, USA.

Objective: To investigate the prognostic significance of p16 in patients with hypopharyngeal squamous cell carcinoma (HPSCC) and to evaluate the relationship between p16 and human papillomavirus (HPV). Unlike in oropharyngeal SCC (OPSCC), the prognostic significance of p16 in HPSCC and its association with HPV is unclear.

Design: Retrospective medical chart review.

Setting: University tertiary referral center.

Patients: A total of 27 patients with HPSCC treated with definitive radiation therapy between 2002 and 2011 whose tissue was available for immunohistochemical analysis.

Interventions: Twenty-two patients were treated with chemoradiation, and 5 with radiation alone. All tumor biopsy specimens were analyzed for p16 and, when sufficient tissue was available, for HPV DNA.

Main Outcome Measures: Overall survival (OS), locoregional control (LRC), disease-free survival (DFS), and laryngoesophageal dysfunction-free survival (LEDFS) were analyzed according to p16 status.

Results: Findings for p16 were positive in 9 tumors and negative in 18 tumors. Median follow-up was 29.3 months. There was no significant difference in OS, LRC, DFS, or LEDFS for patients with p16-positive vs p16-negative tumors. Only 1 of the 19 tumors tested for HPV was found to be HPV positive. When used as a test for HPV, p16 had a positive predictive value of 17%.

Conclusions: In contrast to OPSCC, p16 expression in patients with HPSCC had a low positive predictive value for HPV and did not predict improved OS, LRC, DFS, or LEDFS. Thus, for HPSCC, p16 is not a prognostic biomarker. Caution must be taken when extrapolating the prognostic significance of p16 in patients with OPSCC to patients with head and neck SCC of other subsites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1001/archoto.2012.950DOI Listing
June 2012