At the recent Department of Defense Impact Conference Nicholas Bruchovsky, M.D., Ph.D., of Vancouver General Hospital and the University of British Columbia reported that an intermittent androgen blockade appears to delay the progression from treatable androgen-dependent cancer to untreatable androgen-independent disease. There has been an on going discussion about the difference in efficacy between a constant hormone blockade and an intermittent schedule, which includes periods off the blockade (sometimes with an 5 AR Inhibitor like Proscar or Avodart).

Dr. Bruchovsky said “We like to say that we are hitting the cancer with a flyswatter rather than using a sledgehammer,” thus minimizing the many negative side effects that men suffering with advanced prostate cancer on a blockade suffer.

He ran a single-arm treatment trial that included 103 men, the observed survival rate at six years is about 80%, he said. The expected survival is about 70%, he added (not statistically significant). He used men who had undergone radiation for treatment of their primary prostate cancer, but whose rising PSA indicated a recurrence of the disease. The men were treated with androgen suppression until the PSA normalized at 4 mcg/L. He then followed the men and when PSA again rose to about 10 mcg/L, the patients underwent further treatment with Lupron until their PSA dropped again.

“Biochemical recurrence after irradiation of localized prostate cancer proved amenable to cyclic androgen suppression with a high response rate,” Dr. Bruchovsky said. “About 95% of the patients in the study did respond.”

The time between treatments — after suppressing PSA to below 4 mcg/L lasted as long as 75 weeks following the first treatment. The time off-treatment before the PSA rebound was shorter. For example, after the second treatment limit, the off-treatment season was about 60 weeks. After the third treatment, the off-treatment intermediate time was about 39 weeks.

Very shockingly, Dr. Bruchovsky did state that the lower the PSA went down, the shorter the interval between treatments! “Nadir PSA was a powerful diviner of early to androgen independence,” he said.

Intermittent androgen blockade should be discussed with your oncologist. Not only will it offer you control of your rising PSA, but it will limit the degradation of your life style. However, you must remain vigilant about monitoring your PSA.

Joel T Nowak, MA, MSW