Wednesday, April 3, 2013 (Last Updated: 04/04/2013)
Maha Hussain, M.D., from the University of Michigan in Ann Arbor, and colleagues analyzed data from 1,535 men with metastatic hormone-sensitive prostate cancer who had been receiving a luteinizing hormone-releasing hormone analog and an antiandrogen agent for seven months. If prostate-specific antigen levels fell to 4 ng per milliliter or lower after treatment, the men were randomly assigned to continuous or intermittent androgen deprivation.
After a median follow up of 9.8 years, the researchers found that median survival was lower for the intermittent therapy group (5.1 versus 5.8 years, hazard ratio 1.10, 90 percent confidence interval, 0.99 to 1.23). Erectile function and mental health were significantly better after intermittent therapy, but only at three months. The two groups had similar numbers of treatment-related high-grade adverse events.
"In patients with metastatic hormone-sensitive prostate cancer, the confidence interval for survival exceeded the upper boundary for noninferiority, suggesting that we cannot rule out a 20 percent greater risk of death with intermittent therapy than with continuous therapy, but too few events occurred to rule out significant inferiority of intermittent therapy," Hussain and colleagues conclude.
The study was partly funded by AstraZeneca.