Weekly paclitaxel versus ADT alone in localized high-risk prostate cancer: Results of a single-institution phase II trial.

Abstract

37 Background: Adjuvant chemotherapy’s role after radical prostatectomy (RP) remains controversial in localized high-risk prostate cancer (HRPC). This phase II trial assessed the combination of weekly paclitaxel (WP) with androgen deprivation therapy (ADT) in this population. Methods: All eligible patients (pts) had undergone a laparoscopic RP with pelvic lymph node dissection for a localized HRPC defined with ≥1 of the following criteria: T3b-T4 post-operated Gleason score (GS) ≥8, PSA≥ 20 ng/mL, pN+, in Henri Mondor Hospital. Pts were randomly assigned to either triptoreline 11.25mg every 3 months during 3 years and 8 cycles of WP 100 mg/ m2 (WP arm, n=21) or triptoreline alone (ADT arm, n=26). The primary endpoint is disease free survival (DFS); events=PSA relapse, clinical and radiographic relapse, death. The planned number of pts was 152. Toxicity results indicated a good tolerability with neutropenic fever in 4.3% (n=1), and no negative impact on QoL in the WP arm (Ploussard, Prostate Cancer Prostatic Dis. 2010). Here we report 8-year DFS and overall survival (OS) results. Results: Between February 2005 and October 2007, 47 pts were enrolled. This trial was terminated prematurely because of slow accrual. After a mean follow-up of 8.4 y, we identified a PSA relapse in 25 pts (53%) and castrate-resistant prostate cancer occurred in 6 pts. No statistically difference was found in terms of either biochemical or clinical DFS (bDFS, cDFS) and OS: 8-year bDFS rate: 50% [n=11/22] in the WP arm vs 46% [n=12/26] in the ADT arm (p=0.79); 8-year cDFS rate: 95.4% [n=21/22] in the WP arm vs 88.5% [n=23/26] in the ADT arm (p=0.38). The 8-year OS rate is 90.9% (n=20/22) and 84.6% (n=22/26) respectively with no difference between treatment arms (p=0.51). No clinical, histological or biological variable demonstrated a difference in either 8-year bDFS, cDFS or OS rate. Conclusions: Provided that this trial is probably underpowered to detect a DFS benefit, adjuvant weekly paclitaxel after RP was not associated with any significant reduction in the risk of biological relapse or death compared to ADT alone in patients with localized HRPC. Chemotherapy should be only proposed in dedicated clinical trial for localized HRPC.