July 25, 2012 — In the past, clinicians and the public have heeded the advice of the United States Preventative Services Task Force (USPSTF) about prostate cancer screening, suggests research published online July 23 in the Archives of Internal Medicine.
After the group's 2008 guidance, which recommended against screening men older than 75 years, the incidence of early-stage disease in older men plunged 25% in the United States.
"There was an immediate decline in the incidence of early-stage prostate cancer tumors among men 75 years and older after the USPSTF recommended against screening this group," writes author David Howard, PhD, from the Department of Health Policy and Management at Emory University in Atlanta, Georgia.
The incidence of early-stage disease is an indicator of the amount of prostate-specific antigen (PSA) testing in a population, he explained.
Dr. Howard found that from 2007 to 2009, the adjusted incidence rate for early-stage tumors in men 75 years and older decreased from 443 to 330 per 100,000 (−25.4%; P < .001). The absolute number of cases declined from 8137 to 6162.
Dr. Howard used data from the Surveillance, Epidemiology, and End Results (SEER) 18 registry, which collects information on newly diagnosed cancer cases in catchment areas.
He challenges recent results that indicated that there was no change in PSA screening rates from 2005 to 2010 (JAMA. 2012;307:1692-1694). The data source for that study was the National Health Interview Surveys, in which American residents self-report health behaviors and diseases. "Self-reported PSA testing measures have poor sensitivity and specificity," scolds Dr. Howard.
An immediate question arises from Dr. Howard's analysis: Will it happen again because of the 2012 USPSTF recommendation against routine testing for all healthy men?
In an unrelated essay (J Clin Oncol. 2012;30:2581-2584), a group of experts assert that the answer is no.
The USPSTF's "blanket rejection" of the PSA test is "unlikely to influence practice," according to Sigrid Carlsson, MD, PhD, from the Memorial-Sloan Kettering Cancer Center in New York City and Göteborg University in Sweden, and colleagues. Dr. Carlsson and her fellow experts wrote an essay criticizing the new USPSTF guideline for a number of "very important errors," as reported by Medscape Medical News.
"PSA testing is not likely to go away," wrote Dr. Carlsson and coauthors.
Dr. Howard voiced similar thoughts in an email to Medscape Medical News.
"Physicians are probably more willing to discontinue screening older patients. There might be more resistance to discontinuing screening among younger, healthier men," he said.
But Dr. Howard also said: "I think it will have an impact. There is growing publicity about the problem of 'overdiagnosis', which might make physicians and some patients more receptive to the USPSTF recommendation."
The recently published PIVOT study might also contribute to the way the new guidance is received, noted Dr. Howard. This major randomized controlled trial found that prostatectomy did not improve survival significantly, compared with observation, in men with localized disease. "This research also casts doubt on the benefits of early detection, which may amplify the impact of the USPSTF recommendation," said Dr. Howard about PIVOT.
Nonetheless, "many men will continue to receive regular PSA tests," he added.
More Details
In addition to finding that the rate of early-stage prostate cancers dropped among older men after the 2008 recommendation, Dr. Howard found that other indicators of PSA testing also dropped.
The incidence of late-stage tumors decreased by 14.3% (P < .001), and the incidence of tumors of unknown stage decreased by 16.8% (P < .001). The incidence of early-stage tumors in men 65 to 74 years decreased by 15.2% (P < .001); in men 30 to 64 years, the incidence decreased by 11% (P < .001).
Overall, Dr. Howard found that 254,184 prostate cancer cases were newly diagnosed during the study period. There were 198,417 early-stage cases, 34,695 late-stage cases, and 21,072 cases of unknown stage. There were 109,053 cases (all stages) in men 30 to 64 years of age, 91,868 cases in men 65 to 74 years, and 53,263 cases in men 75 years and older.
