Long-Term Androgen Deprivation in Patients With Intermediate-Risk Prostate Cancer Does Not Improve Overall Survival


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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 the size of prostate tumors or stall their growth. A secondary analysis of the historic Radiation Therapy Oncology Group (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. The research was recently presented at the American Society for Radiation Oncology’s 55th Annual Meeting.1

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.2 Because some patients with intermediate-risk prostate cancer were included in the study, the current analysis was conducted to determine whether 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 ng/mL, and a Gleason score of 7; or who were immediate-risk prostate cancer patients with T2 disease, PSA of 10 to 20 ng/mL, 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. 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 patients 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 (= .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.” ■

Disclosure: Dr. Mirhadi reported no potential conflicts of interest.

References

1. Mirhadi AJ, Hunt D, Hanks GE, et al: Effect of long-term hormonal therapy (vs short-term hormonal therapy): A secondary analysis of intermediate risk prostate cancer patients. American Society for Radiation Oncology 55th Annual Meeting. Abstract 61. Presented September 23, 2013.

2. Hanks GE, Pajak TF, Porter A, et al: Phase III trial of long-term adjuvant androgen deprivation after neoadjuvant hormonal cytoreduction and radiotherapy in locally advanced carcinoma of the prostate: The Radiation Therapy Oncology Group Protocol 92-02. J Clin Oncol 21:3972-3978, 2003.



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