KEY POINTS
- This phase III randomized trial enrolled 316 patients with biochemical recurrence after radical prostatectomy between 2019 and 2021. Patients were assigned to hypofractionated salvage RT with 65 Gy in 26 fractions or conventional salvage RT with 66 Gy in 33 fractions.
- Intensity-modulated radiotherapy with daily image guidance was delivered to the prostate bed. Elective pelvic nodal irradiation was permitted at the treating oncologist's discretion and was used in 202 patients (68.5%); androgen-deprivation therapy was given to 151 patients (51.2%).
- Median PSA before radiotherapy was 0.36 ng/mL (IQR 0.24–0.49). Endorectal balloons were used in 186 patients (63.1%), an important treatment detail because the gastrointestinal toxicity signal was concentrated predominantly among patients treated without a balloon.
- After median follow-up of 52.6 months, four-year biochemical progression-free survival was 80.1% with hypofractionation versus 78.1% with conventional fractionation. The prespecified superiority endpoint was not met.
- Distant metastasis-free survival was likewise similar at 91.7% versus 91.0%, and prostate cancer-specific survival was 100% in both arms at four years. Patient-reported quality-of-life outcomes were also comparable.
- The clearest difference was gastrointestinal toxicity: four-year cumulative grade ≥2 GI toxicity was 7.9% with hypofractionation versus 0.7% with conventional treatment. Events occurred predominantly in patients without an endorectal balloon, although all reported cases had resolved by the latest follow-up.
- The uploaded source contains the published abstract rather than the full manuscript, so additional details on hazard ratios, randomization stratification, genitourinary toxicity, subgroup analyses and statistical testing beyond the abstract are not available here and have not been inferred.
CLINICAL TAKEAWAY
The shorter 26-fraction salvage regimen did not improve biochemical control, but produced similar four-year cancer outcomes and quality of life to 33 fractions. It may be a practical alternative, but the trial does not by itself prove noninferiority, and the higher grade ≥2 gastrointestinal toxicity means hypofractionation should not be viewed as an uncomplicated one-for-one replacement.