CHICAGO — In patients with high-risk prostate cancer, adjuvant docetaxel without hormone therapy did not improve biochemical disease-free survival after radical prostatectomy, according to findings presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.1
“Adjuvant chemotherapy after surgery has been shown to improve survival and response rate in both metastatic breast and colorectal cancers,” said lead investigator Goran Ahlgren, MD, PhD, urologist at Skane University Hospital in Malmo, Sweden. “We asked whether adjuvant chemotherapy after radical prostatectomy for prostate cancer will improve outcomes as well.”
Because docetaxel therapy has been shown to prolong survival in advanced castration-resistant prostate cancer, researchers evaluated whether or not 6 courses of docetaxel improves biochemical disease-free survival following radical prostatectomy for high-risk locoregional prostate cancer.
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For the phase 3 trial, investigators enrolled 459 patients with an average age of 62.2 years from centers in Denmark, Norway, Sweden, Finland, and Iceland. About 39% had pT3b disease and 37.5% had a Gleason score of 8 to 10. Patients were randomly assigned to receive docetaxel 75 mg/m2 IV every 3 weeks for 6 cycles or surveillance, followed by radical prostatectomy in both arms. Of those assigned to the chemotherapy arm, 5.2% withdrew prior to receiving any chemotherapy and 79.1% received all 6 cycles.
Results showed that at a median follow-up of 56.8 months, 47.9% of patients in the docetaxel arm had biochemical progression, defined as a rising PSA >0.5 ng/mL, compared with 38.9% in the surveillance arm (P=.078).
“We observed an initially lower biochemical progression rate in the chemotherapy arm, but the rate became higher from 6 to 24 months,” Dr Ahlgren noted.
Six prostate cancer-related deaths occurred in the docetaxel group vs only 3 in the surveillance group. Also, 18.7% of docetaxel-treated patients reported febrile neutropenia.
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The study further demonstrated that Gleason score ≥8 (P<.001) and presence of lymph node metastasis (P<.001) were significant predictors of progression, while treatment strategy was not (P=.067).
“Docetaxel without continuous corticosteroids may trigger biochemical progression in patients with a Gleason score ≤7,” Dr Ahlgren concluded.
Reference
- Ahlgren G, Flodgren P, Tammela TLJ, et al. A randomized phase III trial between adjuvant docetaxel and surveillance after radical prostatectomy for high risk prostate cancer: Results of SPCG12. J Clin Oncol. 2016; 34 (suppl; abstr 5001).
