That's because conservative management strategies, deferring treatment until the disease progresses, do not appear to be as risky as previously thought, according to the study published in the Journal of the American Medical Association.
A number of previous studies have found that early, aggressive treatment does not seem to substantially improve mortality rates among men over the age of 65.
However, conservative management strategies are only used in about 10 percent of cases of the often slow-moving disease, which usually strikes late in life.
"Coupled with data showing that the lifetime risk of being diagnosed with prostate cancer is about 17 percent while the corresponding risk of dying of this disease is only about three percent, the evidence suggests that conservative management may be an important treatment consideration for the sizable majority of men diagnosed with localized prostate cancer," wrote lead author Grace Lu-Yao of the Cancer Institute of New Jersey.
Using data from Medicare insurance files, Lu-Yao's team was able to follow 14,516 men diagnosed with prostate cancer whose cases were managed without surgery or radiation for at least six months after diagnosis.
The data covers approximately 97 percent of the US population aged 65 and older and Lu-Yao's team was able to follow the cases for a median of 8.3 years by looking at men diagnosed from 1992 through 2002.
The survival rates were substantially better than in studies of cancers detected before 1992, when use of the early-detection prostate-specific antigen (PSA) test became common. That test allows for the detection of prostate cancer six to 13 years before it presents clinically.
Those older studies found the chance of dying within 10 years from prostate cancer to be 15 to 23 percent among men aged 66 to 74 diagnosed with moderately differentiated tumors who pursued conservative management.
The mortality rate was just six percent among those diagnosed at the same age and stage of the disease in this latest, large scale study.
And the survival rate of 94 percent was actually better than the 90 percent recorded in previous studies for a similar population of men who pursued aggressive treatment.
"The substantial improvement in survival that we observed in our study compared with previous reports might be explained, in part, by additional lead time, overdiagnosis related to PSA testing," changes in the way tumors are graded and advancements in medical care, the authors wrote.