Dec. 19, 2006 Recent findings from an observational study by researchers at the University of Pennsylvania School of Medicine suggest that men between 65 and 80 years of age who received treatment for early stage, localized prostate cancer lived significantly longer than men who did not receive treatment. The study is published in the December 13th issue of the Journal of the American Medical Association.
Thanks to better cancer prevention education and the resulting wide-spread increase in using prostate-specific antigen (PSA) screenings, more men are being diagnosed with early-stage and low-or intermediate-grade prostate cancer. Studies have shown that the slow-developing nature of prostate cancer during its earliest stages makes treatment options, such as a radical prostatectomy (surgical removal of the prostate) and radiation therapy, controversial with unpredictable outcomes. Often, recently diagnosed men of this group were advised to just "watch and wait" to see how their situation progressed.
"For this study we looked back over the existing data of a large population of prostate cancer patients, aged 65 to 80, with small tumors that were at a low or intermediate risk of spreading," said senior author Katrina Armstrong, MD, MSCE, who worked on the study with colleagues from Penn's Abramson Cancer Center, Center for Clinical Epidemiology and Biostatistics, Leonard Davis Institute of Health and Economics, and Division of Internal Medicine, and Fox Chase Cancer Center. "After accounting for all their differences, we discovered that the men -- who within six months of diagnosis underwent surgery or radiation therapy -- were 31 percent less likely to die than those who did not undergo treatment during that time."
Researchers acquired the necessary data for this study from the Surveillance, Epidemiology, and End Results (SEER) Medicare database, a population-based cancer registry which encompasses approximately 14 percent of the US population. Data was included on 44,630 men, aged 65 to 80, who were diagnosed between 1991-1999, with prostate cancer and had survived more than a year after diagnosis. All patients were followed-up until death or December 31st, 2002, the end of the study. Of the 44,630 men, 32,022 (71.8 percent) were actively treated with either surgery or radiation therapy during the first six months after diagnosis. The remaining group of 12,608 (28.3 percent) were classified as having received "observation" and did not undergo surgery, radiation or hormonal therapy.
During the 12-years of follow-up, researchers found that the patients who received treatment had a 31 percent lower risk of death. In the observation-only group, 37 percent of the patients died whereas only 23.8 percent of those in the treatment group died.
Since this was not a randomized, controlled study but a retrospective analysis of existing data, the researches had to perform extensive statistical adjustments to account for study participants differences. Even with all these differences taken into account, there was still a significant improvement in the overall survival of those men who received active treatment. "This benefit was also seen across the board in all subgroups examined, including African-American men and older men aged 75-80 at diagnosis," added Armstrong. "However, as we summarized in the study, because observational data can never completely adjust for potential selection bias and confounding, our results must be validated by rigorous randomized controlled trials of elderly men with localized prostate cancer before the findings can be used to influence treatment decisions."
This study was funded by the Center for Population Health and Health Disparities at the University of Pennsylvania, Public Health Services Grant P50-CA105641.
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