In addition, the trial randomized only men with newly metastatic disease who had achieved a PSA of 4.0 or less after 7 months of CAD with goserelin and bicalutamide – starting 770 patients on IAD and continuing 759 patients to CAD. The median age was 70, about half (48%) had extensive disease, and 14% were African Americans. Men on IAD were monitored monthly and went back on therapy based on predetermined parameters.
If PSA rose to 20 ng/ml in men on IAD or to a pre-registration baseline below 20 ng/ml, therapy was restarted; it could also be restarted based on symptoms. After 7 months, men could take another break if their PSA normalized. An increase to greater than 4 ng/ml on months 6 or 7 would send them back to continuous therapy until progression.
Previous studies enrolled populations with earlier stage disease before physicians could determine whether they were responsive to hormone therapy or not, noted Dr. Roth, professor of medicine in the division of oncology at Washington University School of Medicine. The men in this trial "were the most likely to benefit from hormone therapy."
While the number of men trying IAD is not known, it is used in the United States, Dr. Roth said. He does not offer it to his patients – and will not offer it going forward – but often sees it in the charts of patients referred to him.
"A 2-year difference in median survival is huge," he said, predicting patients would not press for IAD once they discussed the research with their physicians.
"Are you going to trade off hot flashes for a 2-year decrease in median overall survival with IAD?" he proposed asking a patient. "I think the average patient will say, ‘Those hot flashes are not so bad.’"
The investigators disclosed numerous relationships with pharmaceutical companies.
* This story was updated with additional analysis from Dr. Oh on 6/6/2012.