Primary androgen deprivation therapy (PADT) yielded no mortality benefit compared with no PADT in men with clinically localized prostate cancer, according to a new study.
Researchers performed a retrospective cohort study with comprehensive utilization and cancer registry data obtained from 3 health plans: Kaiser Permanente Northern California, Kaiser Permanente Southern California, and Henry Ford Health System in Detroit. Included patients were men who received a new diagnosis of clinically localized prostate cancer between 1995 and 2008, who were followed through December 2010, and who did not receive curative-intent therapy. PADT was defined as gonadotropin-releasing hormone analogue or a gonadotropin-release hormone antagonist with or without an oral antiandrogen received for localized disease in the first 12 months after diagnosis, with no receipt of radiation or radical prostatectomy. The study's main outcomes were all-cause and prostate cancer-specific mortality. The results were published online March 17 by the Journal of Clinical Oncology.
The study included data from 15,170 men, 23% of whom received PADT. Men who received PADT had higher PSA levels and higher Gleason scores than those who did not, such that 58% of the PADT group were considered high-risk by American Urological Association criteria compared with 18% of the no-PADT group. A total of 4,921 men died, 1,049 of causes related to prostate cancer. Median follow-up time was 54 months in the PADT group and 64 months in the no-PADT group. After adjusting for sociodemographic and clinical characteristics, researchers found no association between PADT and risk for all-cause mortality (hazard ratio [HR], 1.04; 95% CI, 0.97 to 1.11) or prostate cancer-specific mortality (HR, 1.03; 95% CI, 0.89 to 1.19). Lower risk for all-cause mortality was associated with PADT only in men who had a high risk for progressive disease (HR, 0.99; 95% CI, 0.78 to 0.97).
The authors noted that residual confounding might have affected their results and that the findings may have limited generalizability, among other limitations. However, they concluded that PADT conferred no mortality benefit when compared with no PADT in most men who had clinically localized prostate cancer and who did not receive therapy intended to cure the disease. PADT may confer a small clinical benefit in men whose risk for progressive disease is high, the authors found.
“Our main conclusion is that PADT does not seem to be an effective strategy as an alternative to no therapy among men diagnosed with clinical localized [prostate cancer] who are not receiving curative-intent therapy,” the authors wrote. “The risks of serious adverse events and the high costs associated with its use mitigate against any clinical or policy rationale for PADT use in these men.” Although the study did find a possible benefit for all-cause mortality in men at high risk for progressive disease, the authors cautioned that prescribing PADT in this population should be done only after careful consideration of the possible harms.