Intermittent androgen deprivation in biochemical recurrence of prostate cancer after radiotherapy

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Jun 29 2006

Intermittent androgen deprivation (IAD) is commonly used in the treatment of CaP, which theoretically may delay the development of hormone resistance.

Dr. Bruchovsky and associates report the outcomes of a Phase II trial using IAD in patients with biochemical recurrence following radiotherapy in the epub version of Cancer.

A group of 103 patients with a PSA of >6ng/ml but no evidence of metastasis were enrolled in the study. They received cyproterone acetate and leuprolide as treatment, with leuprolide given every 4 weeks for up to 8 doses. The leuprolide was then stopped if the PSA level at weeks 24 and 32 was <4.0ng/ml.and resumed when the PSA level was >10ng/ml. Development of androgen independence was defined as 3 sequential increases in the PSA despite castrate levels of serum testosterone.

Mean patient age at study entry was 73 years and mean PSA was 21.2ng/ml. Mean follow-up was 3.7 years. The total number of treatment cycles was 277. The mean time on treatment in cycles 1 and 2 was 36 weeks, which decreased in cycles 3-5. This was because some patients either progressed or reached the end of the study. The average time off treatment was 64 weeks in cycle 1, decreasing 22-27% in cycles 2 –4. Prostate volume decreased in the first 3 cycles (by 40% in cycle 1), but not thereafter.

The main reasons for ending trial participation were end of study in 39%, progression in 24%, and death in 16%. Gleason score had no significant effect on cycle times.

The shortening cycle times are consistent with IAD selecting for patients who have the most androgen-sensitive tumors. This Phase II trial supports that IAD is feasible in this cohort of patients and has few adverse side effects.

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