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

Background: Adjuvant chemotherapy is standard treatment for other solid tumours, but to date has not proven effective in prostate cancer.

Objective: o evaluate whether six cycles of docetaxel alone improve biochemical disease-free survival after radical prostatectomy for high-risk prostate cancer.

Design, setting, and participants: Open-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.

Intervention: Docetaxel treatment after prostatectomy.

Results and limitations: Median 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.

Conclusions: Docetaxel without hormonal therapy did not significantly improve biochemical disease-free survival after radical prostatectomy.

Patient summary: In 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.

Keywords: Adjuvant; Docetaxel; Prostate cancer; Radical prostatectomy; Randomised trial.