ANAHEIM, CaliforniaThe timing of androgen deprivation therapy for prostate cancer may well affect disease-specific survival, according to two studies presented at the American Urological Association annual meeting.
Androgen deprivation therapy is the main treatment for recurrent and metastatic prostate cancer. After an initial high response rate to the therapy, most patients progress to androgen independence. A study from Wayne State University, Detroit (abstract 692), found that intermittent androgen deprivation may delay the time to androgen-independent status.
Emad Youssef, MD, and his colleagues treated 74 patients intermittently with luteinizing hormone-releasing hormone (LHRH) agonists with or without oral antiandrogens between January 1993 and March 2000. The indications were rising PSA level after local treatment (n = 41), bone metastases (n = 9), local recurrence (n = 16), and lymphadenopathy (n = 8).
Patients were treated with intermittent androgen deprivation for 1 to 6 cycles for a median of 21 months (range, 1 to 85 months) and were followed for a median of 60 months.
The study evaluated the pattern of PSA changes with each cycle, the length of each cycle, and the time interval between successive cycles. The time to androgen-independent status and the androgen-independent progression rate and its relation to the initial cause of treatment were quantified.
The main result was a progressive rise in PSA nadir with a progressive decrease in the time between treatment cycles, Dr. Youssef reported. Median PSA before the first cycle was 11.4 ng/mL. Median PSA nadir after each cycle increased progressively: from 0.1 ng/mL after the first cycle to 3.3 ng/mL after the fifth cycle.
The time interval between cycles also decreased progressively, from 9.5 months between the first and second cycles to 6 months between the third and fourth cycles. The median time to androgen-independent status has not been reached, he said, except for patients treated for bone metastases, where it was 18 months.