PROSTATE CANCER Combination therapy may prolong life, study finds
Patients are also spared many ill-effects of therapy.
MILWAUKEE JOURNAL SENTINEL
MILWAUKEE -- Doctors were able to cut the death rate of prostate cancer patients nearly in half and spare them several serious drug side effects by combining radiation therapy with a limited course of hormone therapy, according to a new study.
The finding could have a significant impact on the treatment of men whose cancer is thought to be localized but who are at higher risk because of higher prostate lab test scores. As many as 125,000 men, or about half of all newly diagnosed cases each year, fall into that category, according to lead author Anthony D'Amico, a radiation oncologist at Brigham and Women's Hospital and the Dana-Farber Cancer Institute in Boston.
"This is really the first study to show you can prolong life by adding hormone therapy to local therapy [radiation] ... for men with localized prostate cancer," said D'Amico, also a professor of radiation oncology at Harvard Medical School.
Men getting the combined therapy had an overall five-year survival rate of 88 percent, compared with 78 percent for those who got just radiation.
"That's a huge survival benefit," D'Amico said. "Most cancer advances give you a couple percentage points. They don't give you 10 [percentage points]."
During the study, six of the patients in the radiation group died of prostate cancer and 17 from other causes, compared with no prostate cancer deaths in the combined therapy group and 12 from other causes.
In addition, 43 of the men in the radiation group had disease progression, compared with 21 in the combination therapy group.
Equally important, D'Amico said, was the fact that the men in the combined therapy group were spared many of the ill effects of long-term hormone therapy, which often lasts three years. Long-term hormone therapy can cause osteoporosis, muscle loss, irregular heartbeat, memory loss and other cognitive problems, impotence and breast enlargement. Hormone therapy drugs block the production of testosterone.
However, by limiting androgen suppression therapy to six months, many of those side effects can be limited, although breasts still can become enlarged and there may be temporary erectile dysfunction, he said.
In the study
The study, which appears today in the Journal of the American Medical Association, involved 206 men aged 49 to 82 who received either two months of radiation therapy alone or in combination with six months of androgen suppression therapy.
While biopsies suggested that their cancer was confined to the prostate, they were at a somewhat higher risk because of prostate specific antigen, or PSA, scores of 10 or more, or of a Gleason score -- a grading system for cancerous prostate tissue -- of at least 7. They also may have had radiographic evidence that the cancer had spread beyond the prostate.
Already, doctors are using combination therapy to treat men with more aggressive prostate cancer, said Theodore DeWeese, chairman of radiation oncology at Johns Hopkins University Medical School. Now there is sound evidence that it can be beneficial for men at intermediate risk, said DeWeese, who also wrote an editorial in JAMA accompanying the study.
"I think it's a very significant development," he said in an interview.
The JAMA study used a lower dose of radiation, DeWeese said. What is not known is how the survival rates would have been affected had the researchers used a higher dose. It is possible that survival would have improved in both groups or the radiation group alone, he said.
Either way, the research is likely to change the way doctors treat prostate cancer, he said.
The study also gives doctors confidence about using a shorter course of hormone therapy in men who are at intermediate risk, said Robert Donnell, an associate professor of urology at the Medical College of Wisconsin.
That's important, he said, because some men are less able to endure two or three years of hormone therapy.
"It [the study] gives some rationale for using hormones for a shorter period of time," Donnell said.
What still is needed, Donnell said, is a large study over the course of 10 to 20 years comparing radiation alone and in combination with hormone therapy.