KEY POINTS
- This retrospective single-institution review included 101 patients with high-risk prostate cancer; toxicity was assessed prospectively, with a minimum follow-up of 24 months and median follow-up of 43.8 months.
- Patients received 36.25 Gy in 5 alternate-day fractions to the prostate and 25 Gy in 5 fractions to the pelvic lymph nodes using a simultaneous integrated boost, plus 6–18 months of androgen deprivation therapy.
- Late gastrointestinal toxicity occurred in 4 patients (4%), including 3 grade 2 events; late genitourinary toxicity occurred in 13 patients (13%), including 5 grade 2 events (5%).
- No grade ≥3 gastrointestinal or genitourinary toxicity and no insufficiency fractures were observed.
- Five-year actuarial biochemical recurrence-free, distant metastasis-free, and overall survival were 89.5%, 96.2%, and 98.8%, respectively.
CLINICAL TAKEAWAY
Five-fraction treatment of both the prostate and elective pelvic nodes appears feasible, with low rates of clinically significant late toxicity in this selected cohort. However, the retrospective design, absence of a comparator, variable androgen deprivation duration, and lack of routinely collected patient-reported outcomes mean this regimen should not yet be considered definitively validated; ongoing randomized trials are needed.