Median survival was more than 13 years for men who had surgery or radiation, but only 10 years for those who chose "watchful waiting," according to an analysis of Medicare and federal cancer registry records on nearly 50,000 men.
Looked at another way, men who were treated were half as likely to die - 59 percent of them were alive at the end of the study compared with only 27 percent of the others.
"Even when you adjust for all the differences between the groups, there still is a survival advantage to being treated," said Dr. Yu-Ning Wong of Fox Chase Cancer Center in Philadelphia. She reported the results Saturday at a conference in San Francisco.
Cancer of the prostate, a gland at the base of the penis that makes seminal fluid, is the most common major malignancy in American men. Each year in the United States, there are more than 232,000 new cases and 30,000 deaths from it. Worldwide, there are 680,000 cases and 221,000 deaths. . . . Wong's new study looks at men older than 65 diagnosed in the 1990s with small or not very aggressive tumors confined to the prostate. Within six months of diagnosis, 14,560 chose watchful waiting and 34,046 had surgery or radiation.
After an average of 13 years of follow-up, she compared their survival, taking into account differences in age, tumor size, general health and other factors.
"Even among the men aged 75 to 80, there still was a benefit to treatment," she said.
A study has also found a link between the combination of a virus and a genetic defect with prosate cancer. The virus had previously been linked to cancer in mice, but not in humans. A viral link could both guide treatment of, and simplify detection of prostate cancer.