Cancer Research Lab

Few men newly diagnosed with very low-risk prostate cancer and who are therefore eligible for active surveillance, in lieu of definitive treatment, opt for this approach, new study results indicate.

The findings were reported Thursday in Orlando at The Prostate Cancer Symposium, co-sponsored by the American Society of Clinical Oncology, the American Society of Therapeutic Radiology and Oncology, and the Society of Urologic Oncology.

“Active surveillance, or watchful waiting, appears to be an underutilized management strategy for patients with very low-risk prostate cancer,” said Dr. Daniel Barocas, of New York-Presbyterian Hospital-Weill Cornell Medical College.

Dr. Barocas and colleagues analyzed data from a national prostate cancer registry to determine the percentage of men presenting with very low-risk prostate cancer who were candidates for active surveillance and the number of them who actually chose this course of action.

Among 1,886 men diagnosed with the disease between 1999 and 2004, 310 (16%) were classified as having very low-risk disease based on a combination of five factors that are “highly predictive of indolent tumors,” Dr. Barocas explained.

These factors are a PSA level < 10 ng/mL at diagnosis, a PSA density < 0.15, clinical stage T1 or T2a disease, Gleason score 6 or less with no high-grade pattern 4 or 5 disease, and fewer than one third of the biopsy cores being positive.

The finding that 16% of men met all five criteria “raises concern for overdiagnosis of these indolent tumors,” Dr. Barocas commented.

Only 9% of men meeting lowest-risk criteria chose active surveillance, the researchers found. This “suggests that overtreatment may be a problem,” Dr. Barocas added.

“Up to one in eight American men will develop prostate cancer in their lifetime,” he pointed out, “but if you look at men who die of other causes, 50% or more will actually have microscopic, indolent prostate cancer found at the time of autopsy.”

On multivariate analysis, older age was the only factor predictive of active surveillance. Men between 63 and 70 years of age were 5 times more likely to choose active surveillance than men younger than age 63. Men older than age 70 years were 26 times more likely to choose active surveillance than men younger than age 63 years.