"These results have changed the way I treat patients," said Ian M. Thompson Jr., M.D., director of the Cancer Therapy & Research Center at The University of Texas Health Science Center at San Antonio and senior author on the international study.
Hormone therapy in hormone-sensitive prostate cancer has been shown to help extend the lives of patients, but it causes a range of unpleasant side effects in men like moodiness, hot flashes, bone loss and sexual dysfunction. To give patients relief, doctors have, in some cases, "pulsed" the therapy — giving it to men for a time and then stopping it until the signs of prostate cancer activity reappear, then starting the hormone therapy again until the cancer appears to be under control.
The study shows that the continuous therapy helps men more. Men with less advanced metastatic prostate cancer who received the "pulse" or intermittent hormone therapy died an average of two years sooner than those on continuous therapy. The study results first drew attention when they were announced last summer at the annual meeting of the American Society of Clinical Oncology.
After that, prostate cancer survivor Floyd Balter switched from pulse to continuous therapy.
"Last year Dr. Thompson told me about the study results," said Balter, 78. "I said, 'Let's do it.'"
Surviving 17 years beyond a diagnosis where he'd been given two years to live, Balter said he's determined to watch his grandchildren grow for as long as possible.
"I want to live as long as I can," he said. "I can live with the side effects. They're a pain but I can tolerate them."
In the study results, if men with more extensive disease are included in the group, survival was more modest, extended by an average of 7 months, "which is longer than any other intervention," said Dr. Thompson, director of the CTRC. Often advances in cancer treatments will only extend life by an average of two or three months, he noted.
"I can now give a patient the option of putting up with some side effects in order to spend several more months or even years with his grandchildren," Dr. Thompson said. "I can tell you they are happy to have that choice."
Also, Dr. Thompson pointed out, because of the increase in PSA testing, most men who are diagnosed with metastatic prostate cancer present with disease that is still minimal.
The study followed 1,535 men with metastatic prostate cancer for a median of almost 10 years. It was led by SWOG, an international network of research institutions. The significance of the results, adding months if not years to the lives of many men, means every physician with prostate cancer patients should take them into account, Dr. Thompson said.