Long‐Term Follow‐Up of Patients Treated with Intermittent Hormone Therapy for Advanced Prostate Cancer

Background: To determine the feasibility of long-term use of intermittent hormone therapy (IHT) in patients with advanced prostate cancer. Methods: Sixteen hormone-naive patients were commenced on IHT and prospectively reviewed. IHT consisted of goserelin acetate alone (two patients) or combined with an antiandrogen. When the serum prostate specific antigen (PSA) level had fallen to 10 ng/ml, the same treatment was recommenced, constituting one complete cycle comprising both “on-treatment” and “off-treatment” phases. This was repeated until hormone independence (HI) occurred. Results: The median length follow-up was 49.9 months. Considering all patients, a mean of 41% of the total time was spent off hormone treatment, ranging from a median of 4.0 to 7.1 months for each cycle. Fifteen patients finished at least one complete cycle of IHT, and 7 patients completed two or more cycles. Nine patients became HI after a mean time period of 19.5 months. Six men remain on IHT; three are currently in their fourth or fifth cycle of treatment. For patients completing Cycles 1, 2, 3, 4, and 5, the median percentage time spent off treatment during each cycle was 41%, 54%, 58%, 53%, and 58%, respectively. Conclusions: Based on this pilot study, IHT would seem to allow considerable time off therapy without obviously affecting the time to HI. If the current randomized trials of IHT against continuous therapy demonstrate equivalent relapse-free survival, then quality of life and fiscal end points will be paramount in determining treatment options. An Australian intergroup study to examine these end points has already begun.