Data on intermittent ADT, survival now published

Intermittent androgen deprivation therapy (ADT) may compromise survival for metastatic hormone-sensitive prostate cancer patients compared with continuous ADT, according to a recently published multicenter study.

"We tried to see whether intermittent androgen deprivation is as good as continuous androgen deprivation, but we did not prove that. We found that intermittent therapy is certainly not better, and moreover, we cannot even call it comparable," lead author Maha Hussain, MD, of the University of Michigan Comprehensive Cancer Center, Ann Arbor, said of the findings.

Study data, originally presented at the American Society of Clinical Oncology annual meeting in Chicago in June 2012, were published last week online in the New England Journal of Medicine (April 4, 2013).

The authors treated 1,535 patients with metastatic hormone-sensitive prostate cancer and followed them for a median of 10 years. Men were given an initial course of ADT. Patients with a stable or declining PSA level ≤4.0 ng/mL were then randomly assigned either to continue or to discontinue the hormone therapy. Patients were monitored with monthly PSAs and a physician’s evaluation every 3 months, and therapy was resumed in the intermittent arm when PSA climbed to 20.0 ng/mL. The intermittent cycle continued on and off based on the PSA levels.

Survival between the two groups showed a 10% relative increase in the risk of death with intermittent therapy, with average survival of 5.8 years for the continuous group and 5.1 years for the intermittent group from the time of randomization.

The authors also looked at quality of life between the two groups. Initially, the intermittent therapy group showed significant improvement in erectile dysfunction and emotional function in the first 3 months and had improved trends in other aspects of quality of life compared to the continuous group. But these differences leveled off over time.

"The improvements in some aspects of quality of life that were observed early were not sustained after a few months as patients had to resume therapy," said Dr. Hussain.

"If a patient is coming in with newly metastatic prostate cancer, hormone treatment continuously is the standard. If they wish to do intermittent treatment, they should be counseled that based on this data, their outcome might be compromised."

The study was sponsored by SWOG. Dr. Hussain receives research funding from Abbott Laboratories, Astellas Pharma, Merck Serono, Millennium, and Pfizer.
 

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