About three-quarters of men with low-risk prostate tumors that can safely be ignored for months or years receive aggressive treatment, despite the risk of complications, researchers reported Monday. The findings, published in the Archives of Internal Medicine, shed further light on the ongoing dispute about the levels of prostate-specific antigen (PSA) that should be used to trigger further diagnosis and treatment. Currently, a cutoff of PSA levels of 4.0 nanograms per milliliter is used to decide whether a man needs a biopsy or other follow-up, but some experts are recommending the cutoff be reduced to 2.5. If that were to occur, the authors report, the number of U.S. men considered to have abnormal PSA levels would double to about 6 million, and many more would undergo unnecessary procedures.
Cancer epidemiologist Grace Lu-Yao of the Cancer Institute of New Jersey at the University of Medicine and Dentistry of New Jersey and her colleagues used the federal government's Surveillance, Epidemiology and End Results (SEER) database to study the records of 123,934 men over the age of 25 who had newly diagnosed prostate cancer from 2004 to 2006. About 14% of the men had PSA values lower than 4, generally younger men. In that group, 54% had low-risk disease that could be safely monitored for progression with little risk. Nonetheless, 75% of them received aggressive treatment, including a radical prostatectomy and radiation therapy. Among men in that group over the age of 65, in which "watchful waiting" is generally advised for low-risk disease, 66% had aggressive therapy. In both cases, the percentages were similar to those in the group with PSA levels between 4 and 20. Complications of such aggressive treatment include impotence and incontinence, among other problems.
"It is clear from our current study that men are choosing aggressive forms of treatment when they may not need to," Lu-Yao said in a statement. "This is especially concerning for older men, as previous studies done by our team show excellent disease-specific survival for men with low-risk cancer following conservative management."
More than 192,000 new cases of prostate cancer were diagnosed in this country in 2009, according to the American Cancer Society, and more than 27,000 died from it. More than 90% of all prostate cancers are diagnosed before the disease has spread to other parts of the body, and the five-year survival rate for them is almost 100%. The five-year survival rate for all stages of the disease, both localized and metastatic, increased from 69% in 1975 to almost 99% in 2003, the authors said.
The bottom line, Lu-Yao said, is that clinicians need a better way to distinguish between those tumors that are likely to progress and those that won't.
-- Thomas H. Maugh II