36.25 Gy versus 40 Gy in five fractions of curative stereotactic body radiotherapy for prostate cancer: a propensity score-matched analysis.

Authors

Hideomi Yamashita, Daichi Sugahara, Subaru Sawayanagi, Yuki Nozawa, Hanano Mizumoto, Hiroyuki Ueno, Atsuto Katano

Published in

Clinical and translational radiation oncology. Volume 62. Pages 101281. Epub Sep 19, 2026.

Abstract

This study aimed to determine whether 36.25 Gy was inferior to 40 Gy in terms of prostate-specific antigen (PSA) recurrence following stereotactic body radiation therapy (SBRT) for prostate cancer.
We retrospectively reviewed the medical records of 863 consecutive patients with prostate cancer treated at a single institution between 2016 and 2025. Propensity score (PS) matching based on age, pre-treatment PSA level, biopsy Gleason score, clinical T-stage, National Comprehensive Cancer Network (NCCN) risk classification, and concomitant androgen-deprivation therapy (ADT) yielded 530 patients for analysis. Patients received SBRT at a total dose of 36.25 or 40 Gy in five fractions administered every other day. The prespecified non-inferiority margin was a hazard ratio of 1.40.
After PS matching, no significant differences remained in baseline characteristics that had differed significantly between the two groups before matching. In the 36.25-Gy and 40-Gy groups, respectively, 16 and 10 PSA recurrences and 18 and 10 deaths occurred. Four PSA recurrences (15%) occurred over 5 years. The 5-year event-free survival (EFS) rates were 90% with 36.25 Gy and 88% with 40 Gy (p = 0.37). The hazard ratio for EFS with 36.25 Gy versus 40 Gy was 0.76 (95% confidence interval [CI], 0.42-1.39; p = 0.37). The 5-year PSA recurrence-free rates were 95% and 93%, respectively (p = 0.76). Among the 298 patients receiving 36.25 Gy, grade 3 gastrointestinal (GI) and genitourinary (GU) toxicities occurred in 2.3% and 1.3%, respectively. Among the 565 patients receiving 40 Gy, grade 3 or GI toxicity occurred in 1.9%, and grade ≥ 3 GU toxicity occurred in 0.8%. No grade 5 toxicity occurred. Urinary and bowel quality of life (QOL) scores decreased at 1 month and returned to near-baseline levels by 3 months.
In this retrospective study, the findings suggest that the 36.25-Gy regimen may be non-inferior to 40 Gy for EFS and may be associated with fewer grade 4 toxicities and better urinary QOL. Given the retrospective design, these findings should be considered hypothesis-generating.

PMID:
42830848
Bibliographic data and abstract were imported from PubMed on 05 Oct 2026.

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