1. Gantry-Based 5-Fraction Elective Nodal Irradiation in Unfavorable-Risk Prostate Cancer: Outcomes From 2 Prospective Studies Comparing SABR Boost With MR Dose-Painted HDR Brachytherapy Boost
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Andrea Deabreu, Hans T. Chung, Ananth Ravi, Danny Vesprini, William Chu, Andrew Loblaw, Gerard Morton, Patrick Cheung, Ling Ho, Hima Bindu Musunuru, Stanley K. Liu, M. Davidson, Liying Zhang, and Joelle Helou
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Cancer Research ,medicine.medical_specialty ,Radiation ,business.industry ,medicine.medical_treatment ,Brachytherapy ,Context (language use) ,medicine.disease ,SABR volatility model ,Radiation therapy ,Androgen deprivation therapy ,Prostate cancer ,medicine.anatomical_structure ,Oncology ,Prostate ,medicine ,Radiology, Nuclear Medicine and imaging ,Radiology ,business ,Prospective cohort study - Abstract
Background ASCO/CCO guidelines recommend brachytherapy boost for intermediate-risk (IR) or high-risk (HR) prostate cancer (PCa) patients. Stereotactic ablative body radiotherapy (SABR) is an emerging technique for PCa but its use in HR disease is limited. We compare efficacy, toxicity, and quality-of-life (QoL) in patients treated on 2 prospective protocols that used SABR boost or MR-guided HDR brachytherapy boost (MR-HDR) with 6-18 months of androgen deprivation therapy (ADT). Methods In XXXXXX study (study 1), patients received 40Gy to prostate and 25Gy to pelvis in 5 weekly fractions. In XXXXXX (study 2), patients received HDR-BT 15Gy x 1 to the prostate and ≤22.5Gy to the MRI nodule, followed by 25Gy in 5 weekly fractions to pelvis. All patients received between 6 and 18 months of androgen deprivation therapy. Results Thirty patients (NCCN 7% unfavorable IR, and 93% HR) completed study 1 while 31 patients (NCCN 3% favorable IR, 47% Unfavorable IR and 50% HR) completed treatment as per study 2. Median follow-up was 72 and 62 months, respectively. In study 2, 6 patients had BF and all 6 developed metastatic disease. Actuarial 5-year BF was 0% for study 1 and 18.2% for study 2 (p=0.005). There was no significant difference in worst acute or late GI or GU toxicity. Grade 3 late GU toxicity was noted in 3% of the patients in study 2 (HDR-BT boost). There was no significant difference in QoL or minimally clinical important change. Conclusions In the context of 5-fraction pelvic radiotherapy and ADT, there does not appear to be a significant difference in toxicity or QoL between SABR vs. HDR BT boost. While efficacy favored the SABR boost cohort, this should be viewed in the context of limitations and biases associated with comparing two sequential phase II studies.
- Published
- 2022
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