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.
Reference:
Cancer. 2006 Jun 16; [Epub ahead of print]
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