Men with low-risk prostate cancer have appreciable disease-specific mortality, study shows.
ANAHEIM, Calif.—Fifteen percent of older men managed with watchful waiting for low-risk prostate tumors detected by PSA screening will die from the malignancy in 10 years, despite a high death rate from competing causes, a study found.
Researchers at Northwestern University in Chicago followed 36,000 men who had enrolled in a prostate cancer screening study from 1989 to 2001. A total of 3,565 of the participants had prostate cancer detected via biopsy. Of these, 347 (10%) opted for watchful waiting as primary management. All the men were then followed prospectively for a mean of eight years with biannual PSA measurements.
The 347 men had a mean age of 75 (range 48-90 years) and mean PSA level of 5.4 ng/mL (range: 0.1-45 ng/mL). All but one had had clinically localized disease.
At the end of the study, the men had an overall mortality rate of 45%, with 15% of the deaths from prostate cancer, the investigators reported here at the American Urological Association annual meeting. Among the 347 prostate cancer patients, 33% underwent additional treatment and 20% had PSA progression (defined as PSA doubling time of less than three years).
The investigators concluded that the 10-year actuarial prostate cancer death rate was 15%. A higher PSA at time of diagnosis and PSA progression predicted death from prostate cancer, the researchers concluded.
“This is really the first study to look at PSA-screened prostate cancer in a long-term follow-up study,” said investigator Bradley A. Erickson, MD, a fourth-year urology resident. “The thing that is unique about this is that we never intended to treat these patients, thinking that they would die of other possible causes before the pros-tate cancer would cause symptoms.
“This really gives us the natural history of PSA-screen-detected prostate cancer,” he continued.
The findings suggest that patients with low-risk prostate cancer have appreciable progression and disease-specific mortality rates, said co-investigator William Catalona, MD, professor of urology at Northwestern’s Feinberg School of Medicine.
“For those patients who have watchful waiting or active monitoring, we see that some of them will slip through the cracks and ultimately die of prostate cancer when earlier treatment may have resulted in a different or more favorable outcome,” Dr. Catalona said.
“This is especially impressive, considering the general advanced age and high competing risk for mortality in this specific patient group. One would anticipate the prostate cancer-specific mortality rate would be far higher in a group of younger patients with a longer life expectancy.”