Moderate hypofractionation for salvage radiotherapy (HYPO-SRT) in patients with biochemical recurrence after prostatectomy: A cohort study with meta-analysis

To assess the effectiveness and safety of HYPO-SRT in patients with biochemical recurrence after radical prostatectomy, we performed a cohort study followed by meta-analysis (MA).

A cohort study followed by a MA was designed to evaluate the biochemical relapse-free survival (bRFS) and toxicity rates with HYPO-SRT for patients with a biochemical recurrence after radical prostatectomy. Following the PRISMA and MOOSE guidelines, eligible studies were identified on electronic databases through February 2021. A meta-regression analysis was performed. A p-value <0.05 was considered significant.

A cohort of 43 patients treated by HYPO-SRT was prospectively evaluated. With a median follow-up of 31 months, at 3 years, the bRFS was 93%. In the cohort study, the incidence of late grade 1, 2, and ≥3 GU and GI toxicities were 33% and 20%, 2% and 4%, and 0% and 0%, respectively. Combining our cohort with 5 studies, a total of 412 patients treated with HYPO-SRT were included in the MA. The 3-year bRFS was 73% (95% CI: 63-83%). The estimation of bRFS at 5 years was 61%. The rate of grade ≥2 late GU and GI toxicity was 6 % (95% CI: 1-12), and 3% (95% CI: 1-5), with no toxicities grade 3-5. In the meta-regression, % residual PSA, % positive margins, % ADT and % ≥ Gleason 8 had a significant association with bRFS (all P < 0.05). The late GU toxicity was associated with EQD2Gy_1.5 ≥ 70 Gy (p = 0.01).

HYPO-SRT produced satisfactory bRFS with reduced acute/ late GU and GI toxicity rates. The MA analysis supports future studies assessing HYPO SRT.