A study that includes 20 years of follow-up does not support aggressive treatment for localized, low-grade prostate cancer, with data indicating a small risk of progression of this grade of cancer, according to a study in the May 4 issue of JAMA.
To determine the need for treatment of localized prostate cancer, patients and physicians must understand the natural history of this disease, according to background information in the article. A recent study suggested an increasing prostate cancer death rate for men who are alive more than 15 years following diagnosis. The appropriate therapy for men with clinically localized prostate cancer has been uncertain.
Peter C. Albertsen, M.D., M.S., of the University of Connecticut Health Center, Farmington, Conn., and colleagues conducted a study to determine whether prostate cancer death rates declined, remained constant, or increased after 15 years. The researchers used data from the Connecticut Tumor Registry, supplemented by hospital record and histology review of 767 men aged 55 to 74 years with clinically localized prostate cancer diagnosed between January 1, 1971, and December 31, 1984. Patients were treated with either observation or immediate or delayed androgen withdrawal therapy, with an observation period of 24 years being the norm.
The researchers found: "Extended follow-up of our competing risk analysis suggests that prostate cancer progression rates do not increase after 15 years of follow-up. Men with low-grade prostate cancer have only a small risk of prostate cancer progression even after 20 years of management by observation or androgen withdrawal therapy alone. These results do not support aggressive treatment of localized low-grade prostate cancer. Men with poorly differentiated disease (Gleason scores of 7 and 8-10) have a high risk of death from prostate cancer; only 3 men were alive after 20 years. Men with moderate-grade disease (Gleason scores of 5-6) have an intermediate cumulative risk of prostate cancer progression after 20 years of follow-up."
"Our data provide what are likely overestimates of prostate cancer progression when men are treated by observation or androgen withdrawal therapy alone. Only through randomized controlled trials designed to measure the efficacy of screening and treatment for prostate cancer can we answer questions concerning which patients may truly benefit," the authors conclude.
(JAMA. 2005;293:2095-2101. Available post-embargo at JAMA.com)
Editor's Note: This study was funded by a grant from the Agency for Healthcare Research and Quality.
Editorial: The Natural History of Clinically Localized Prostate Cancer
In an accompanying editorial, Peter H. Gann, M.D., Sc.D., and Misop Han, M.D., of the Feinberg School of Medicine, Northwestern University, Chicago, comment on predicting the natural history of prostate cancer.
"Over the next 20 years there will be pronounced improvements in the ability of … models to predict not only true stage but outcomes based on blood or biopsy samples available at diagnosis. These predictors will come not only from more detailed analysis of routine biopsy features, but from the application of new molecular technologies. Indeed, one thing that is safe to predict right now is that in 20 years, commentators discussing on the natural history of prostate cancers diagnosed in the early 21st century will conjecture that what happened to those cases is too difficult to interpret or altogether irrelevant," they write.
(JAMA. 2005;293:2149-2151. Available post-embargo at JAMA.com)
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