Publications by authors named "G Brandon Gunn"

368 Publications

Mixed effect modelling of dose and Linear Energy Transfer correlations with brain image changes after intensity modulated proton therapy for skull base head and neck cancer.

Int J Radiat Oncol Biol Phys 2021 Jun 18. Epub 2021 Jun 18.

The University of Texas MD Anderson Cancer Center, Department of Radiation Oncology, Houston, USA.

Purpose: Intensity modulated proton therapy (IMPT) could yield high Linear Energy Transfer (LET) in critical structures and increased biological effect. For head and neck cancers at the skull base this could potentially result in radiation associated brain image change (RAIC). The purpose of the current study was to investigate voxel-wise dose and LET correlations with RAIC after IMPT.

Material And Methods: For 15 patients with RAIC after IMPT, contrast enhancement observed on T1 weighted MRIs were contoured and co-registered to the planning CT. Monte Carlo calculated dose- and dose averaged LET (LET) distributions were extracted at voxel level and associations with RAIC were modelled using uni- and multivariate mixed effect logistic regression. Model performance was evaluated using the area under the Receiver Operating Characteristic Curve (AUROC) and Precision-Recall Curve (AUPRC).

Results: An overall statistically significant RAIC association with dose and LET was found in both the uni- and multivariate analysis. Patient heterogeneity were considerable with SD of the random effects of 1.81 (1.30 - 2.72) for dose and 2.68 (1.93 - 4.93) for LET, respectively. AUROC was 0.93 and 0.95 for the univariate dose-response model and multivariate model, respectively. Analysis of the LET effect demonstrated increased risk of RAIC with increasing LET for the majority of patients. Estimated probability of RAIC with LET = 1 keV/µm was 4% (95% CI: 0%, 0.44%) and 29% (95% CI: 0.01, 0.92%) for 60 Gy and 70 Gy, respectively. The TD were estimated to be 63.6 Gy and 50.1 Gy with LET equal to 2 keV/µm and 5 keV/µm, respectively.

Conclusion: Our results suggest that the LET effect could be of clinical significance for some patients; LET assessment in clinical treatment plans should therefore be taken into consideration.
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http://dx.doi.org/10.1016/j.ijrobp.2021.06.016DOI Listing
June 2021

Proton Therapy for HPV-Associated Oropharyngeal Cancers of the Head and Neck: a De-Intensification Strategy.

Curr Treat Options Oncol 2021 Jun 4;22(6):54. Epub 2021 Jun 4.

Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX, 77030, USA.

Opinion Statement: The rise in the incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPC), the relatively young age at which it is diagnosed, and its favorable prognosis necessitate the use of treatment techniques that reduce the likelihood of side effects during and after curative treatment. Intensity-modulated proton therapy (IMPT) is a form of radiotherapy that de-intensifies treatment through dose de-escalation to normal tissues without compromising dose to the primary tumor and involved, regional lymph nodes. Preclinical studies have demonstrated that HPV-positive squamous cell carcinoma is more sensitive to proton radiation than is HPV-negative squamous cell carcinoma. Retrospective studies comparing intensity-modulated photon (X-ray) radiotherapy to IMPT for OPC suggest comparable rates of disease control and lower rates of pain, xerostomia, dysphagia, dysgeusia, gastrostomy tube dependence, and osteoradionecrosis with IMPT-all of which meaningfully affect the quality of life of patients treated for HPV-associated OPC. Two phase III trials currently underway-the "Randomized Trial of IMPT versus IMRT for the Treatment of Oropharyngeal Cancer of the Head and Neck" and the "TOxicity Reduction using Proton bEam therapy for Oropharyngeal cancer (TORPEdO)" trial-are expected to provide prospective, level I evidence regarding the effectiveness of IMPT for such patients.
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http://dx.doi.org/10.1007/s11864-021-00847-yDOI Listing
June 2021

The State of Portuguese-American Health Disparities.

Acta Med Port 2021 Mar 1;34(3):171-172. Epub 2021 Mar 1.

Georgia State University. Atlanta. Georgia. United States.

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http://dx.doi.org/10.20344/amp.15659DOI Listing
March 2021

Association of Risk Factors With Patient-Reported Voice and Speech Symptoms Among Long-term Survivors of Oropharyngeal Cancer.

JAMA Otolaryngol Head Neck Surg 2021 May 6. Epub 2021 May 6.

Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston.

Importance: Voice and speech production are critical physiological functions that affect quality of life and may deteriorate substantially after oropharyngeal cancer (OPC) treatment. There is limited knowledge about risk factors associated with voice and speech outcomes among survivors of OPC.

Objective: To identify the risk factors of voice and speech symptoms among long-term survivors of OPC.

Design, Setting, And Participants: This retrospective cohort study with cross-sectional survivorship survey administration includes cancer-free survivors of OPC who were treated curatively between January 2000 and December 2013 at MD Anderson Cancer Center (Houston, Texas) who participated in a survey from September 2015 to July 2016. Of 906 survivors of OPC with a median survival duration at time of survey of 6 years (range, 1-16 years), patient-rated voice and speech outcomes for 881 were available and analyzed. The data were analyzed from June 30, 2020, to February 28, 2021.

Main Outcomes And Measures: The primary outcome variable was patient-reported voice and speech scores that were measured using the MD Anderson Symptom Inventory-Head and Neck Cancer Module. Voice and speech scores of 0 to 4 were categorized as none to mild symptoms, and scores of 5 to 10 were categorized as moderate to severe symptoms. Risk factors for moderate to severe voice and speech symptoms were identified by multivariable logistic regression.

Results: Among 881 survivors of OPC (median [range] age, 56 [32-84] years; 140 women [15.5%]; 837 White [92.4%], 17 Black [1.9%], and 35 Hispanic individuals [3.8%]), 113 (12.8%) reported moderate to severe voice and speech scores. Increasing survival time (odds ratio [OR], 1.17; 95% CI, 1.06-1.30) and increasing total radiation dose (OR, 1.16; 95% CI, 1.00-1.34), Black race (OR, 3.90; 95% CI, 1.02-14.89), Hispanic ethnicity (OR, 3.74; 95% CI, 1.50-9.35), current cigarette smoking at the time of survey (OR, 3.98; 95% CI, 1.56-10.18), treatment with induction and concurrent chemotherapy (OR, 1.94; 95% CI, 1.06-3.57), and late (OR, 7.11; 95% CI, 3.08-16.41) and baseline lower cranial neuropathy (OR, 8.70; 95% CI, 3.01-25.13) were risk factors associated with moderate to severe voice and speech symptoms. Intensity-modulated radiotherapy split-field regimen (OR, 0.31; 95% CI, 0.12-0.80; P = .01) was associated with lower likelihood of moderate to severe voice and speech symptoms.

Conclusions And Relevance: This large OPC survivorship cohort study identified many treatment-related factors, including increasing total radiotherapy dose, multimodality induction and concurrent chemotherapy regimens, and continued smoking, as well as clinical and demographic factors, as risk factors that were associated with moderate to severe voice and speech symptoms. The key findings in this study were the protective associations of split-field radiation and that longer-term survivors, and those who continued to smoke, had worse voice and speech symptoms. These findings may inform research and effective targeted clinical voice and speech preservation interventions and smoking cessation interventions to maximize voice and speech function and address quality of life among patients with OPC.
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http://dx.doi.org/10.1001/jamaoto.2021.0698DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8103354PMC
May 2021

Role of induction chemotherapy for oral cavity squamous cell carcinoma.

Cancer 2021 Apr 28. Epub 2021 Apr 28.

Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas.

Background: Patients with locoregionally advanced oral cavity squamous cell carcinoma (OCSCC) have a poor survival outcome. Treatment involves extensive surgery, adjuvant radiation, or chemoradiation and results in high morbidity. In this study, the authors' objective was to evaluate their experience with induction chemotherapy (IC) in the treatment of locoregionally advanced OCSCC.

Methods: A retrospective review of the medical records of all patients with locoregionally advanced (stage III and IV) OCSCC who received IC followed by definitive local therapy was conducted. Outcomes included response to IC and survival.

Results: In total, 120 patients were included in the study. The overall stage was stage IV in 79.2% of patients. After 2 cycles of IC, 76 patients (63.3%) achieved at least a partial response, including 13 who had a complete response. Stable disease was observed in 30 patients (25%), and 14 patients (11.7%) had progressive disease. Among responders, 16 patients received definitive chemoradiation or radiation therapy, and 60 underwent surgical resection, of whom 15 had less extensive surgery than was originally planned. Overall, organ preservation was achieved in 40.8% of patients who had a favorable response to IC. The 5-year overall and disease-specific survival rates were 51.4% and 66.9%, respectively. Patients who had at least a partial response had better 5-year overall survival (60.1%) and disease-specific survival (78.5%) compared with nonresponders (33.8% and 46.4%, respectively).

Conclusions: The results demonstrate a response rate to IC in patients with advanced OCSCC similar to what has been observed in patients with cancer in other head and neck subsites. Patients who achieved at least a partial response to IC had a more favorable outcome, with ensuing organ preservation. Further studies are warranted.
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http://dx.doi.org/10.1002/cncr.33616DOI Listing
April 2021