Long-term HT does not improve overall survival in intermediate-risk prostate cancer
Men with intermediate-risk prostate cancer who received long-term hormonal therapy (HT) after radiation had no additional benefits compared to short-term hormonal therapy. This data was presented at the 55th annual meeting of the American Society for Radiation Oncology in Atlanta, Georgia.
Men with advanced prostate cancer typically receive hormonal therapy to reduce the level of androgens, or male hormones, in their bodies. Although hormone therapy alone will not cure prostate cancer, lowering androgen levels can reduce the size of prostate tumors or stall their growth.
This study was a secondary analysis of the historic RTOG 9202 trial, which evaluated the potential benefits of long-term adjuvant androgen deprivation for two 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 androgen deprivation.
Researchers reviewed all patients enrolled in RTOG 9202 whose prostate cancer was categorized as intermediate-risk based on T2 disease (tumor confined to the prostate), a prostate specific antigen (PSA) of less than 10 ng/mL, and a Gleason Score of 7; or, who were immediate-risk with T2 disease, PSA of 10 to 20 ng/mL and a Gleason Score less than 7. A total of 133 patients were analyzed.
The long-term androgen deprivation group consisted of 59 patients, and the short-term androgen deprivation group consisted of 74 patients. The median follow-up was more than 11 years.
No statistical difference was found in overall survival, with 10-year estimates of 61% for the short-term androgen deprivation group and 65% for the long-term 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 deprivation group and in 33 in the long-term androgen deprivation group. Ten-year PSA failure rates were 53% for the short-term androgen deprivation group and 55% for the long-term 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 lead author Amin Mirhadi, MD, a radiation oncologist at Cedars-Sinai Medical Center in Los Angeles, California. "This data supports administering less treatment, which will result in fewer side effects and reduce patients' overall health care costs."