ASTRO: Long-Term Androgen Deprivation in Patients With Intermediate-Risk Prostate Cancer Does Not Improve Overall Survival
A secondary analysis of the historic RTOG 9202 prostate cancer trial examined results of men with intermediate-risk prostate cancer who had received long-term hormonal therapy after radiation therapy. Investigators concluded that there were no additional benefits when compared to short-term hormonal therapy, according to research presented today at the American Society for Radiation Oncology’s 55th Annual Meeting (Abstract 61).
Men with advanced prostate cancer typically receive hormonal therapy to reduce the level of androgens in their bodies. Although hormone therapy alone will not cure prostate cancer, lowering androgen levels can reduce prostate tumors size or stall their growth.
Study Details
The original RTOG 9202 trial evaluated the potential benefits of long-term adjuvant androgen deprivation for 2 years after initial androgen deprivation when compared to short-term (initial) androgen therapy in mostly high-risk prostate cancer patients receiving external beam radiation therapy. Because some intermediate-risk prostate cancer patients were included in the study, the current analysis was conducted to determine if patients in the intermediate-risk subset experienced an additional survival benefit with long-term adjuvant androgen deprivation therapy.
Researchers reviewed all patients enrolled in RTOG 9202 categorized with intermediate-risk prostate cancer with T2 disease (tumor confined to the prostate), a prostate specific antigen (PSA) of < 10 and a Gleason Score of 7; or, who were immediate-risk prostate cancer patients with T2 disease, PSA of 10 to 20 and a Gleason Score < 7. A total of 133 patients were analyzed. The long-term adjuvant androgen deprivation group consisted of 59 patients, and the short-term androgen therapy group consisted of 74 patients. Statistical analysis was used to determine overall survival, disease-specific survival, and PSA failure rates, and the median follow-up was more than 11 years.
Outcomes
There was no statistical difference in overall survival with 10-year estimates of 61% for the short-term androgen therapy group and 65% for the long-term adjuvant androgen deprivation group. Disease-specific survival was found to be 96% in both groups. PSA failure occurred in 38 patients in the short-term androgen therapy group and in 33 in the long-term adjuvant androgen deprivation group. Ten-year PSA failure rates were 53% for the short-term androgen therapy group and 55% for the long-term adjuvant androgen deprivation group (P = .99).
“Most clinicians have felt that ‘more was better’ when it came to blocking testosterone in prostate cancer patients, however, results for the specific endpoints we focused on, overall survival and disease-specific survival, indicate that this was clearly not the case,” said Amin Mirhadi, MD, lead author of the study and a radiation oncologist at Cedars-Sinai Medical Center in Los Angeles. “These data support administering less treatment, which will result in fewer side effects and reduce patients’ overall health-care costs.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
