CHICAGO, IL USA (UroToday.com) - Adding docetaxel to standard hormone and radiation therapy reduced the risk of death for men with high-risk, localized prostate cancer in results reported at the 2015 ASCO Annual Meeting, in Chicago, IL. At a median follow-up of 5.5 years in this phase III study RTOG 0521, overall survival (OS) rates were 93% in the docetaxel-treated group vs. 89% in the standard therapy group.
Docetaxel also reduced the risk of relapse, with 5-year disease-free survival rates of 73% in the docetaxel group and 66% in patients in receiving standard therapy.
“This is the first indication that chemotherapy has a role in the adjuvant treatment of localized prostate cancer,” said lead author Howard Sandler, MD, professor of radiation oncology at Cedars-Sinai Medical Center in Los Angeles, CA. “This finding could improve outcomes for thousands of men.”
The trial opened December 2005 and closed August 2009, with a targeted accrual of 600 patients. It was designed to detect improvement in 4-year OS from 86% to 93%, with a 51% hazard reduction (HR=0.49).
Three groups of eligible patients had: 1) Gleason (Gl) 7-8, any T-stage, PSA > 20; 2) Gl 8, ≥ T2, any PSA, or 3) Gl 9-10, any T-stage, any PSA. All patients had PSA ≤ 150.
Of 612 enrolled patients group, 562 were evaluable. Patients had a mean age of 66 years and median PSA = 15.1. A total of 53% had Gleason scores of 9-10; 27% had cT3-4 disease.
At the median follow-up of 5.5 years, 4 year OS rates were 89% ([95% CI: 84-92%] for the AS + RT arm and 93% [95% CI: 90-96%] for the AS+RT+CT arm (1-sided, p=0.03, HR = 0.68 [95% CI:0. 44, 1.03]). A total of 52 deaths occurred in the AS+RT arm, and 36 deaths were recorded in the AS+RT+CT arm. Fewer deaths, both due to prostate cancer or to treatment and due to other causes, occurred in the AS+RT+CT arm.
Five-year disease-free survival rates were 66% for AS+RT-treated patients and 73% for AS+RT+CT (2-sided p=0.05, HR=0.76 [95% CI:0.57, 1.00]).
Toxicity was acceptable in this trial. One grade 5 unlikely treatment-related adverse event occurred in the AS+RT arm, and 2 Grade 5 adverse events, possibly or probably treatment-related, occurred the AS+RT+CT arm.
Follow-up of study patients will continue to ascertain the long-term benefits of adjuvant chemotherapy in this setting. An analysis of quality-of-life data will also be undertaken at a later time, and future study will include an investigation of the impact of adjuvant therapies in men with high-risk prostate cancer.
Providing an ASCO perspective on this important trial, Dr. Charles J. Ryan, commented, “Adjuvant chemotherapy has delivered major survival gains to people with several of the most common types of cancer, and now we are finally seeing the same with prostate cancer. Here we have a powerful new use for a long-established therapy. It’s an advance that would not have been possible without federally funded clinical trials.”
(This study received funding from the National Institutes of Health (NIH), Sanofi, and Astra-Zeneca.)
Sandler HM, Hu Chen, Rosenthal SA, et al. LBA5002: A phase III protocol of androgen suppression (AS) and 3DCRT/IMRT vs. AS and 3DCRT/IMRT followed by chemotherapy (CT) with docetaxel and prednisone for localized, high-risk prostate cancer (RTOG 0521).
Presented by Howard Sandler, MD at the American Society of Clinical Oncology (ASCO) Annual Meeting - Illumination & Innovation: Transforming Data into Learning - May 29 - June 2, 2015 - Chicago, Illinois USA
Cedars-Sinai Medical Center, Los Angeles, CA USA
Written By: Barbara Jones for UroToday