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Is Progress in Prostate Cancer a Result of PSA?

TOP - Daily

A University of Rochester Medical Center (URMC) analysis suggests that early detection and the prostate-specific antigen (PSA) test can prevent up to 17,000 cases of metastatic prostate cancer per year. In fact, projecting incidence rates from age-specific pre-PSA era to the present day would result in tripling the number of men whose cancer had already spread at diagnosis.

“Our findings are very important in light of the recent controversy over PSA testing,” said Edward M. Messing, MD, study coauthor, chair of Urology at URMC, and president of the Society of Urologic Oncology. “Yes, there are trade-offs associated with the PSA test and many factors influence the disease outcome. And yet our data are very clear: not doing the PSA test will result in many men presenting with far more advanced prostate cancer. And almost all men with metastasis at diagnosis will die from prostate cancer.”

In 2011, the US Preventive Services Task Force recommended against PSA screening in all men. These recommendations caused some confusion, and in response an American Society of Clinical Oncology panel of experts decided that general screening with the PSA test should be discouraged for men with a life expectancy of less than 10 years. However, for men with a longer life expectancy, it is recommended that physicians discuss the appropriateness of the PSA test with each patient.

Messing’s study, published in the journal Cancer, analyzed the effect of screening on stage of disease at initial diagnosis. Messing, along with Emelian Scosyrev, PhD, assistant professor of urology, reviewed Surveillance, Epidemiology, and End Results (SEER) data from 1983 to 2008. They compared SEER data from the pre-PSA era (1983 to 1985) with data from the current era of widespread PSA use (2006 to 2008) and adjusted for age, race, and geographic variations in the United States population.

The data showed 8000 cases of prostate cancer with metastases at initial presentation occurred in the US in 2008. To estimate the number of metastatic cases that would occur in 2008 in the absence of PSA screening, Scosyrev and Messing used a mathematical model to calculate that number to be 25,000.

Because the study is observational and has some limitations, it is impossible to know if the PSA test and early detection is solely responsible for the fewer cases of metastasis at diagnosis in 2008, the authors state. Also, the potential lead-time of screening should be considered when interpreting the study findings, Scosyrev said. For example, in cases where the metastasis remains undetected at the time of screening, an early stage at diagnosis may not translate into better survival.

In general, however, the study concluded that massive screening and PSA awareness efforts during the 1990s and early 2000s resulted in substantial shifts toward earlier-stage disease and fewer cases of metastases at diagnosis.

Source: University of Rochester Medical Center.