Post-Radiotherapy Docetaxel for Intermediate-, High-Risk Prostate Cancer Is Not Beneficial

In a phase 3 clinical trial, adjuvant docetaxel without prednisone failed to improve biochemical disease-free survival following radiotherapy (RT) plus androgen deprivation therapy for intermediate- or high-risk prostate cancer (PCa), according to data presented at the 2018 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois, on Monday, June 4.¹

The trial (ClinicalTrials.gov Identifier: NCT00653848), led by Pirkko-Liisa Irmeli Kellokumpu-Lehtinen, MD, PhD, of the University of Tampere in Tempere, Finland, included 376 patients randomly assigned to receive either 6 cycles of adjuvant docetaxel 75 mg/m² every 3 weeks without continuous prednisone (arm A, 188 men, mean age 66.2 years) or surveillance (arm B, 188 men, 66.4 years) following radiotherapy (RT). Adjuvant/neoadjuvant androgen deprivation therapy was mandatory for all patients. The primary endpoint was a PSA rise of 2 ng/mL or more above the nadir PSA value. The investigators defined intermediate- or high-risk prostate cancer as stage T2 tumors with Gleason score (GS) 4+3 and PSA level greater than 10 ng/mL; stage T2, GS 8–10, and any PSA level; or any stage T3 tumors.

Follow-up was 5 years, with PSA measured every 3 months for 2 years, and then every 6 months thereafter. The median follow-up was 59.4 months. All 6 cycles were completed in 147 (78.2%) of patients in arm A.

The primary endpoint was reached in 30.7% of patients: 31% in arm A and 30.3% in arm B. Kaplan-Meier analysis revealed no significant difference between the biochemical disease-free survival curves (P = 0.631).

A total of 43 patients died during the trial: 20 in arm A (9 from PCa) and 23 in arm B (7 from PCa).

According to Dr Kellokumpu-Lehtinen’s team, 16.1% of docetaxel recipients experienced febrile neutropenia, but no deaths in this group were related to docetaxel treatment. On multivariate analysis, GS was a significant predictor of PSA progression.

Read more of Cancer Therapy Advisor‘s coverage of the American Society of Clinical Oncology (ASCO) 2018 meeting by visiting the conference page.

Reference

1. Kellokumpu-Lehtinen PLI, Hjälm-Eriksson M, Astrom L, et al. A randomized Phase III trial between adjuvant docetaxel and surveillance after radical radiotherapy for intermediate and high risk prostate cancer: Results of SPCG-13 trial. J Clin Oncol. 2018: 36, (suppl; abstr 5000). Presented at 2018 ASCO Annual Meeting; June 1-5, 2018; Chicago, IL.