Docetaxel Versus Surveillance After Radical Prostatectomy for High-risk Prostate Cancer: Results from the Prospective Randomised, Open-label Phase 3 Scandinavian Prostate Cancer Group 12 Trial

Abstract

BackgroundAdjuvant chemotherapy is standard treatment for other solid tumours, but to date has not proven effective in prostate cancer. Objectiveo evaluate whether six cycles of docetaxel alone improve biochemical disease-free survival after radical prostatectomy for high-risk prostate cancer. Design, setting, and participantsOpen-label, randomised multinational phase 3 trial. Enrolment of 459 patients after prostatectomy. Inclusion criteria: high-risk pT2 margin positive or pT3a Gleason score ≥4+3, pT3b, or lymph node positive disease Gleason score ≥3+4. Patients assigned (1:1) to either six cycles of adjuvant docetaxel 75mg/m2 every 3 wk without daily prednisone (Arm A) or surveillance (Arm B) until endpoint was reached. Primary endpoint was prostate-specific antigen progression ≥0.5 ng/ml. InterventionDocetaxel treatment after prostatectomy. Results and limitationsMedian time to progression, death, or last follow-up was 56.8 mo. Primary endpoint was reached in 190/459 patients—the risk of progression at 5 yr being 41% (45% in Arm A and 38% in Arm B). There was evidence of nonproportional hazards in Kaplan-Meier analysis, so we used the difference in restricted mean survival time as the primary estimate of effect. Restricted mean survival time to endpoint was 43 mo in Arm A versus 46 mo in Arm B (p=0.06), a nonsignificant difference of 3.2 mo (95% confidence interval: 6.7 to –1.5 mo). A total of 116 serious adverse events were recorded in Arm A and 41 in Arm B with no treatment-related deaths. Not all patients received docetaxel by protocol. The endpoint is biochemical progression and some patients received radiation treatment before the endpoint. ConclusionsDocetaxel without hormonal therapy did not significantly improve biochemical disease-free survival after radical prostatectomy. Patient summaryIn this randomised trial, we tested whether chemotherapy after surgery for high-risk prostate cancer decreases the risk of a rising prostate-specific antigen. We found no benefit from docetaxel given after radical prostatectomy.