Dose-Intensified Postoperative Radiation Therapy for Prostate Cancer: Seven-Year Outcomes from the PKUFH Randomized Phase III Trial

Abstract

<h3>Purpose/Objective(s)</h3> Our purpose was to compare biochemical control, cancer specific survival (CSS) and overall survival (OS) in postprostatectomy patients treated with conventional (66 Gy) or dose-intensified (72 Gy) radiation therapy. <h3>Materials/Methods</h3> Patients who had stage pT3-4, positive surgical margins, or rising prostate-specific antigen≥0.2ng/mL after radical prostatectomy were randomly assigned to receive either 66 Gy in 33 fractions or 72 Gy in 36 fractions. A primary endpoint was to assess the difference in biochemical progression-free survival (bPFS) between these 2 cohorts. bPFS, CSS, OS was estimated by the Kaplan-Meier method. <h3>Results</h3> Between September 2011 and November 2016, 144 patients were enrolled: 71 patients to the 66 Gy cohort and 73 patients to the 72 Gy cohort. The median follow-up time was 89.5 months (range, 14-120 months). There was no difference in 7-year bPFS between the 72 Gy and 66 Gy cohorts (70.3% vs 61.2%; <i>P</i>=0.274). However, in patients with a higher Gleason score (8-10), the 72 Gy cohort had statistically significant improvement in bPFS compared with the 66 Gy cohort (66.5% vs 30.2%; <i>P</i>=0.012). The 7-year CSS was not different between the 2 cohorts, at 94.1% and 96.6% for the 72 Gy and 66 Gy cohorts, respectively (<i>P</i>=0.775). The 7-year OS was not different at 92.8% and 94.1% for the 72 Gy and 66 Gy cohorts, respectively (<i>P</i>=0.594). <h3>Conclusion</h3> Dose escalation (72 Gy) demonstrated no improvement in 7-year bPFS, CSS and OS compared with the 66 Gy regimen. Patients with higher GS (8-10) might benefit from this high dose (72 Gy) regimen.