1. A Pooled Toxicity Analysis of Moderately Hypofractionated Proton Beam Therapy and Intensity Modulated Radiation Therapy in Early-Stage Prostate Cancer Patients
- Author
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Eric M. Horwitz, Bradley J. Stish, Randal H. Henderson, Amardeep S. Grewal, Brian J. Davis, Rahul D. Tendulkar, Joseph K. Salama, Elizabeth Handorf, David Carpenter, Neha Vapiwala, Nancy P. Mendenhall, Jonathan J. Paly, Devon J. Godfrey, J. Karen Wong, and Carlos Vargas
- Subjects
Male ,Organs at Risk ,Cancer Research ,medicine.medical_specialty ,Urology ,Article ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Prostate cancer ,0302 clinical medicine ,Risk Factors ,Proton Therapy ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Aged ,Neoplasm Staging ,Radiation ,business.industry ,Genitourinary system ,Rectum ,Prostatic Neoplasms ,Cancer ,Odds ratio ,Middle Aged ,Intensity-modulated radiation therapy ,medicine.disease ,Confidence interval ,Oncology ,030220 oncology & carcinogenesis ,Toxicity ,Radiation Dose Hypofractionation ,International Prostate Symptom Score ,Radiotherapy, Intensity-Modulated ,business - Abstract
Purpose Data comparing moderately hypofractionated intensity modulated radiation therapy (IMRT) and proton beam therapy (PBT) are lacking. We aim to compare late toxicity profiles of patients with early-stage prostate cancer treated with moderately hypofractionated PBT and IMRT. Methods and Materials This multi-institutional analysis included patients with low- or intermediate-risk biopsy-proven prostate adenocarcinoma from 7 tertiary referral centers treated from 1998 to 2018. All patients were treated with moderately hypofractionated radiation, defined as 250 to 300 cGy per daily fraction given for 4 to 6 weeks, and stratified by use of IMRT or PBT. Primary outcomes were late genitourinary (GU) and gastrointestinal (GI) toxicity. Adjusted toxicity rates were calculated using inverse probability of treatment weighting, accounting for race, National Comprehensive Cancer Network risk group, age, pretreatment International Prostate Symptom Score (GU only), and anticoagulant use (GI only). Results A total of 1850 patients were included: 1282 IMRT (median follow-up 80.0 months) and 568 PBT (median follow-up 43.9 months). Overall toxicity rates were low, with the majority of patients experiencing no late GU (56.6%, n = 1048) or late GI (74.4%, n = 1377) toxicity. No difference was seen in the rates of late toxicity between the groups, with late grade 3+ GU toxicity of 2.0% versus 3.9% (odds ratio [OR] 0.47; 95% confidence interval 0.17-1.28) and late grade 2+ GI toxicity of 14.6% versus 4.7% (OR 2.69; confidence interval 0.80-9.05) for the PBT and IMRT cohorts, respectively. On multivariable analysis, no factors were significantly predictive of GU toxicity, and only anticoagulant use was significantly predictive of GI toxicity (OR 1.90; P = .008). Conclusions In this large, multi-institutional analysis of 1850 patients with early-stage prostate cancer, treatment with moderately hypofractionated IMRT and PBT resulted in low rates of toxicity. No difference was seen in late GI and GU toxicity between the modalities during long-term follow-up. Both treatments are safe and well tolerated.
- Published
- 2021
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