Ultrahypofractionated Versus Conventionally Fractionated Whole-pelvis Radiotherapy in Prostate Cancer: A Randomized Clinical Trial.

BACKGROUND AND

OBJECTIVE

The role of ultrahypofractionated (UH) whole-pelvis radiotherapy (WPRT) as an alternative to conventionally fractionated (CF) WPRT is not well defined.

METHODS

HOPE is a phase 2, multi-institutional, unblinded, randomized clinical trial designed to compare toxicity and patient-reported outcomes between UH-WPRT and CF-WPRT using the Expanded Prostate Cancer Index Composite (EPIC-50) questionnaire at 1 yr after treatment. Eighty patients with unfavorable intermediate-risk, high-risk, or very high-risk disease for whom high-dose-rate prostate brachytherapy was planned were randomly assigned 1:1 to either CF-WPRT or UH-WPRT.

KEY FINDINGS AND LIMITATIONS: Baseline clinical characteristics were similar for the CF-WPRT (39 patients) and UH-WPRT (41 patients) arms. All patients received treatment according to their randomization allocation. Median follow-up was 3.34 yr. At 1 yr after radiotherapy, the mean (± standard deviation) EPIC bowel function score was noninferior between the CF-WPRT and UH-WPRT arms (88.4 ± 12.1 vs 90.6 ± 11.1; p = 0.0016 for noninferiority). Similarly, the mean EPIC bowel total score (86.7 ± 14.2 vs 89.0 ± 12.3; p = 0.24) and bother score (85.0 ± 18.0 vs 87.4 ± 16.3; p = 0.28) did not significantly differ between the arms. No significant differences in EPIC urinary subdomains at 1 yr were observed between the arms. No late (>6 wk) grade 3-5 genitourinary or gastrointestinal toxicities were reported in the CF-WPRT arm, while one patient in the UH-WPRT arm experienced grade 3 genitourinary toxicity. The data are not yet mature enough for evaluation of oncological endpoints.

CONCLUSIONS AND CLINICAL IMPLICATIONS: Results from the HOPE trial demonstrate that UH-WPRT is as well tolerated as CF-WPRT when combined with a high-dose-rate brachytherapy boost to the prostate.