New findings from an observational study suggest that elderly men who received treatment for localized prostate cancer survived significantly longer than men who did not receive treatment, according to a study in the December 13 issue of JAMA; however, the investigators emphasize the importance of validating these results in randomized trials.
The widespread adoption of prostate-specific antigen (PSA) screening has led to an increasing proportion of men being diagnosed with early-stage and low " or intermediate "grade prostate cancer. Studies have demonstrated the slow-developing nature of low- and intermediate-grade prostate cancer, making management options (observation, radiation therapy, and radical prostatectomy) controversial, with uncertain outcomes. This is also applies to men older than 65 years, because of a lack of information from randomized trials. When randomized controlled trial data are not available, observational studies can provide insight into important clinical questions, according to background information in the article.
Yu-Ning Wong, M.D., of the Fox Chase Cancer Center, Philadelphia, and colleagues evaluated the association of active treatment (radiation or prostatectomy) vs. observation on overall survival in a large sample of elderly men treated for low " or intermediate "risk localized prostate cancer. The researchers used data from the Surveillance, Epidemiology, and End Results (SEER) Medicare database, a population-based cancer registry encompassing approximately 14 percent of the U.S. population.
This study included data on 44,630 men age 65 to 80 years who were diagnosed between 1991-1999 with prostate cancer and who had survived more than a year past diagnosis. Patients were followed up until death or study end (December 31, 2002). Patients were classified as having received treatment (n = 32,022) if they had claims for radical prostatectomy or radiation therapy during the first 6 months after diagnosis. They were classified as having received observation (n = 12,608) if they did not have claims for radical prostatectomy radiation or hormonal therapy. Patients who received only hormonal therapy were excluded.
The researchers found that patients who received treatment had a 31 percent lower risk of death during the 12-years of follow-up. In the observation group, 4,643 patients died (37 percent) and 7,639 patients (23.8 percent) in the treatment group died. Active treatment was associated with a significant improvement in survival in the study overall. A benefit associated with treatment was seen in all subgroups examined, including older men (age 75-80 years at diagnosis), black men, and men with low-risk disease.
"In summary, even though prostate cancer commonly is considered an indolent [slow to develop and painless] disease, this observational study suggests a reduced risk of mortality associated with active treatment for low- and intermediate-risk prostate cancer in the elderly Medicare population examined. Because observational data can never be free of concerns about selection bias and confounding, these results must be validated by rigorous randomized controlled trials of elderly men with localized prostate cancer before the findings can be used to inform treatment decisions," the authors write. (JAMA. 2006;296:2683-2693)