BACKGROUND: Hypofractionated salvage radiotherapy is increasingly used for biochemical recurrence of prostate cancer post-prostatectomy, yet its toxicity profile remains underexplored. This study evaluates the incidence, timing, and resolution of treatment-related toxicities in this setting. METHODS: A retrospective cohort study of 403 men receiving hypofractionated salvage radiotherapy (62.5 Gy in 25 fractions) from 2017 to 2024 was conducted. Toxicities, categorized as genitourinary (hematuria, urinary incontinence, frequency, dysuria) or gastrointestinal (rectal bleeding, diarrhea, proctitis, nausea), were graded (1-3) using CTCAE-based criteria. Outcomes included any-time incidence, Kaplan-Meier time-to-first-event estimates (12- and 24-month cumulative incidence), and first-onset timing. Episode-level analyses merged events ≤ 30 days apart, assessing resolution and intervention. RESULTS: Median follow-up was 18.2 months. Any-grade genitourinary and gastrointestinal toxicities occurred in 34.2% and 24.6% of patients, respectively (24-month incidence: genitourinary 40.4%; gastrointestinal 28.9%). Grade 2+ toxicities were less frequent (genitourinary 9.7%; gastrointestinal 7.7%), with Grade 3+ rare (genitourinary 1.7%; gastrointestinal 0.7%). In terms of patient-level ever-event incidences, common symptoms included urinary incontinence (20.3%), rectal bleeding (19.9%), and hematuria (13.9%). Urinary toxicities predominantly onset at 6-12 months, whereas rectal bleeding and hematuria emerged later (≥ 12 months). Approximately two-thirds of Grade 2+ episodes resolved (e.g., urinary incontinence, 66.7%; rectal bleeding, 69.2%), with median resolution times of 3.0-8.4 months. CONCLUSION: With a median follow-up of 18.2 months, hypofractionated salvage radiotherapy demonstrates favorable short-to-intermediate term tolerability, with infrequent severe toxicities. Vigilant monitoring for late-onset rectal bleeding and hematuria is recommended during the 6-24 months after treatment to optimize patient management. Longer follow-up is required to confirm long-term safety.
Jang et al. (Sun,) studied this question.