May 19 (Bloomberg) -- Prostate cancer screening beginning from ages 44 to 50 may rule out the risk of dying in half of men, according to a study that showed some men may need as few as three screening tests in a lifetime.
The research, which analyzed blood samples donated in the 1970s by 12,090 Swedish men, showed that 44 percent of prostate cancer deaths in the ensuing years occurred in 10 percent of men with the highest levels of PSA, a protein associated with prostate cancer at high levels. The study may help reduce unnecessary tests and treatment, said the researchers at Memorial Sloan-Kettering Cancer Center.
Screening for prostate cancer has been the subject of controversy for years as the disease is slow growing in most men. In 2009, a European study of 182,000 men found that 48 men were diagnosed and treated for each prostate cancer death prevented. Prostate cancer treatment can cause impotence, incontinence and other side effects.
“Everyone agrees there is too much overdiagnosis and overtreatment of small, early prostate cancer now,” study co-author Peter Scardino, chairman of surgery at Memorial Sloan-Kettering Cancer Center in New York, said in a telephone interview. Focusing most screening on men at higher risk based on initial PSA results “could conservatively eliminate half the men who are getting screened unnecessarily.”
The study looked at Swedish men ages 44 to 50 who gave blood samples starting in 1974 before PSA testing become common. Almost 5,000 of the men gave repeat blood samples six years later from ages 51 to 55, and a third group of 1,167 men gave blood samples at age 60. It will be presented at the American Society of Clinical Oncology meeting next month in Chicago and was released yesterday in summary form.
New Screening Guide
Researchers said a test that shows below median levels of PSA before age 50 may not rule out the risk of advanced cancer years later. By age 60, however, men who had below median PSA levels were unlikely to ever get metastatic prostate cancer, according to the study. The findings suggest that results of a man’s first PSA test can be used to guide screening in the future. Men with very high PSA levels on the initial test should be screened every year, Scardino said.
An estimated 217,730 new cases of prostate cancer were diagnosed in the U.S. in 2010 and the disease will kill about 32,000 patients, according to the National Cancer Institute.
While recommendations vary, the American Cancer Society suggests that men with an average risk of prostate cancer start discussing the matter with their doctors at age 50. Men often get tests for PSA, or prostate-specific antigen, about every year, said Scardino. PSA levels vary over time and can be elevated because of inflammation, prostate enlargement, and other benign causes.
Based on the study findings, men ages 44 to 50 whose initial PSA screens show low levels of the protein wouldn’t need another test for five years. If PSA level remain low, men could get their final test at 60.
A PSA reading below the median level for that age suggests no more PSA tests are needed, because they “are unlikely to have any problems in terms of quality or length of life from prostate cancer,” said lead author Hans Lilja, a clinical chemist at Memorial Sloan-Kettering Cancer Center. A man may need no more than three PSA tests in a lifetime, researchers said.
Each PSA test costs about $50, according to Otis Brawley, chief medical officer of the American Cancer Society.
“If this approach works, it’s going to decrease the needless treatment,” Brawley said. “This is early promising news.” Still, the Memorial Sloan-Kettering study results need to be confirmed and replicated in other groups of men, he said.
The strategy “makes a lot of sense,” said Gerald Andriole, chief of urologic surgery at the Washington University School of Medicine in St. Louis. “It says: Let’s not waste our time and money screening men with very low PSAs because all we are going to do is create a lot of anxiety and a lot of biopsies and find some cancers that are not likely to kill them.”
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