Hypofractionated radiotherapy for prostate cancer (HYDRA): an individual patient data meta-analysis of randomised trials in the MARCAP consortium

Abstract

Background: Trials comparing moderately hypofractionated radiotherapy (MHFRT) to conventionally-fractionated radiotherapy (CFRT) for prostate cancer have varied considerably in intent (non-inferiority vs superiority) and MHFRT dose. We compare the efficacy and toxicity profiles of isodose MHFRT and dose-escalated MHFRT.

Methods: This was an individual patient data meta-analysis that identified randomised phase 3 trials of CFRT versus MHFRT that had published individual patient-level data on efficacy and late toxicity. A systematic literature search using MEDLINE, Embase, trial registries, the Web of Science, Scopus, and relevant conference proceedings was initially conducted on Dec 15, 2023, and was re-conducted on Jan 8, 2025. Trials that did not publish efficacy data, did not publish late toxicity data, or did not use modern dose radiotherapy (≥70 Gy in 2 Gy equivalents) in the CFRT group were excluded. Individual patient data were provided to MARCAP by study investigators. Three separate meta-analyses were designed to compare efficacy (primary endpoint was progression-free survival), physician-scored late toxicity (co-primary endpoints were late grade 2 or higher genitourinary and late grade 2 or higher gastrointestinal toxic effects), and patient-reported outcomes (co-primary endpoints were clinically-significant decrements in patient-reported urinary or bowel quality of life) between patients receiving CFRT versus MHFRT.

Findings: We identified 1696 records for review. Seven phase 3 trials comparing MHFRT with CFRT were eligible for inclusion in our analysis. Individual patient data were obtained from these seven studies (3454 patients from three trials comparing CFRT with isodose MHFRT and 2426 patients from four trials comparing CFRT with dose-escalated MHFRT). At a median follow-up of 5·4 years (IQR 4·6-7·2) for isodose MHFRT and 7·1 years (5·7-8·4) for dose-escalated MHFRT, no differences in progression-free survival were detected (hazard ratio 0·92, 95% CI 0·81-1·05; p=0·21 and 0·94, 0·82-1·09; p=0·43 respectively). No increased odds of grade 2 or higher genitourinary toxic effects were identified for either isodose (odds ratio [OR] 1·16, 95 CI% 0·86-1·57; p=0·32) or dose-escalated MHFRT (1·20, 0·95-1·51; p=0·13). The odds of grade 2 or higher gastrointestinal toxic effects were significantly higher with dose-escalated (OR 1·48, 95% CI 1·14-1·92; p=0·0035) but not isodose MHFRT (1·30, 0·59-2·87; p=0·51). Isodose MHFRT was not found to show different odds of urinary quality-of-life decrement (OR 1·03, 95% CI 0·51-2·09; p=0·93) or bowel quality-of-life decrement (0·76, 0·40-1·43; p=0·39). Dose-escalated MHFRT was associated with greater odds of bowel quality-of-life decrement (OR 1·68, 95% CI 1·07-2·61; p=0·023), but no evidence of greater urinary quality-of-life decrement was found (1·57, 0·87-2·85; p=0·13).

Interpretation: Isodose MHFRT and dose-escalated MHFRT both have similar efficacy compared with CFRT, but dose-escalated MHFRT is associated with higher physician-scored and patient-reported bowel toxicity. Isodose regimens, eg, 60 Gy in 20 fractions, should be the standard MHFRT regimen for localised prostate cancer.

Funding: None.