Study Suggests Overdetection of PSA Recurrence After Prostatectomy

Almost a third of older men with PSA recurrence after radical prostatectomy had low-risk prostate cancer that was unlikely to progress to metastatic disease, results of a competing-risks analysis suggested.

Among men who had PSA recurrence within 10 years of prostatectomy, 31.4% of those older than 70 at recurrence did not die of prostate cancer, suggesting overdetection of PSA recurrence in that age group,Ruth Etzioni, PhD, of Fred Hutchinson Cancer Research Center in Seattle, and colleagues reported inClinical Cancer Research.

"Previous studies have indicated that the interval from PSA recurrence to metastasis is quite long, with a median of more than 8 years, even in the absence of any treatment for the recurrence," Etzioni said in a statement. "Given that the majority of prostate cancer patients are older, we expect that many would die of other causes before reaching the point of metastasis."

The findings were based on a study of three groups of patients with prostate cancer: 441 men treated at Johns Hopkins, 4,455 patients from the Cancer of the Prostate Strategic Urologic Research Endeavor (CapSURE) database, and NCI's Surveillance, Epidemiology, and End Results database, which captures data on a representative national sample of cancer patients.

The authors used the data to create a simulation model of 1 million virtual patients of different ages and disease characteristics. The objective was to estimate the percentage of patients with PSA recurrence who would die of causes other than prostate cancer. They performed calculations for recurrence within 5 years and within 10 years of radical prostatectomy.

Overall, the results showed that 9.1% of patients with PSA recurrence at 5 years had low-risk disease and would have died of other causes before the cancer progressed to lethality. At 10 years, the proportion increased to 15.6% of the patients. In a subgroup analysis of men who were older than 70 at PSA recurrence, the proportion increased to 31.4%.

Each death by a cause other than prostate cancer was considered overdetection of PSA recurrence. Overdetection means that a large number of men may undergo unnecessary salvage therapy.

"Salvage therapy for prostate cancer patients includes radiation therapy -- which has side effects such as bowl problems and urinary symptoms -- and hormone therapy, which can cause hot flashes, fatigue, loss of libido, and, in the long run, has been linked with osteoporosis, heart disease, and even diabetes," said Etzioni.

"Our findings are in line with treatment studies showing that immediate salvage therapy following detection of rising PSA levels is not the right thing for everyone. We need to develop ways to determine who needs salvage therapy and when to give it."