The impact of PSA testing frequency on prostate cancer incidence and treatment in older men.

To quantify the downstream impact of PSA testing on cancer characteristics and utilization of cancer therapies among men aged 70 or older, we utilized patients diagnosed with prostate cancer in 2004-2005 in the Surveillance, Epidemiology and End Results (SEER)-Medicare and their Medicare claims before their cancer diagnosis during 2000-2005. Among men in the highest testing group (4-6 PSA tests), 75% were diagnosed with low- or intermediate-risk of disease, but 77% received treatments within 180 days of cancer diagnosis. More than 45% of newly diagnosed patients in 2004-2005 had 4-6 PSA tests before their cancer diagnosis during 2000-2005. Men in the high testing group were 3.57 times more likely to receive cancer treatments (either surgery, radiation or hormonal therapy) when compared with men who had no previous PSA testing during the same time period. Among men aged 75+ diagnosed with low-risk cancer, men in the high testing group were 78% more likely to receive treatment than those who had no previous PSA testing. In conclusion, given the lack of evidence of effective treatment for elderly patients diagnosed with low- and intermediate-risk prostate cancer and our inability to distinguish indolent from aggressive cancer, more frequent PSA testing among elderly population may exacerbate the risk of overdiagnosis and overtreatment.