Salvage hypofractionated RT (post-prostatectomy BCR)

Background

Phase 3 randomized trial (N=316) in intermediate- to high-risk prostate cancer with biochemical recurrence after radical prostatectomy. Compared hypofractionated accelerated salvage radiotherapy with conventionally fractionated salvage radiotherapy to the prostate bed (elective pelvic nodal irradiation at physician discretion; IMRT with daily image guidance).

Results

Interventions and follow up: Arm A: HYPO — 65 Gy in 26 fractions (hypofractionated accelerated)
Arm B: CONV — 66 Gy in 33 fractions (conventional)
Primary endpoint: biochemical progression-free survival (bPFS)
mFollow up: 52.6 months
Results: bPFS (4-yr): 80.1% (HYPO) vs 78.1% (CONV) — not superior
DMFS (4-yr): 91.7% vs 91.0%
CSS (4-yr): 100% vs 100%

Adverse events

Grade ≥2 GI (4-yr cumulative): 7.9% (HYPO) vs 0.7% (CONV), predominantly without endorectal balloon; all resolved by last follow-up
Patient-reported QoL: comparable between arms

Conclusions

Hypofractionated accelerated salvage radiotherapy was not superior to conventional fractionation for 4-year bPFS but produced comparable oncologic and quality-of-life outcomes in a shorter course. Given equivalent efficacy, hypofractionation is a viable salvage option, with attention to GI toxicity when an endorectal balloon is not used.

Key Limitations

Powered to detect superiority rather than formal non-inferiority, so equivalence cannot be firmly concluded; higher grade ≥2 GI toxicity with hypofractionation absent an endorectal balloon; bPFS is a surrogate endpoint and follow-up (52.6 mo) is too short for metastasis or survival differences; single-institution.

Clinical Context

Salvage radiotherapy is standard for post-prostatectomy biochemical recurrence (NCCN, ASTRO). Moderate hypofractionation is established in definitive prostate RT; these data extend a shorter, resource-sparing schedule to the salvage setting. No regulatory action; informs fractionation choice.

References