Eliminating the PSA (prostate-specific antigen) test to screen for prostate cancer would be taking a big step backward, according to researchers at the University of Rochester Medical Center (URMC). Without this type of screening, more men would present with metastatic disease at the point of diagnosis.
Prostate cancer, a disease that usually occurs in older men, is the second-leading cause of cancer death in the male population. In 2012, an estimated 241,740 new cases will be diagnosed, and 28,000 deaths will occur. Diagnosis depends on whether the cancer has spread outside the prostate gland.
The URMC study suggests that the PSA test and early detection may prevent up to 17,000 metastatic cases per year. Data shows, in fact, that a lack of PSA testing could triple the cases of advanced prostate cancer.
"Our findings are very important in light of the recent controversy over PSA testing," Edward M. Messing, MD, chairman of urology at the URMC and a co-author of the study, said in a press release. "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 Preventative Services Task Force recommended against offering all men PSA screening, creating quite a stir in the medical community. After reviewing scientific data, the government concluded that screening has little or no benefit, and that the harms of early detection outweigh the benefits. The biggest concern seems to be that doctors are finding and treating non-aggressive cancers that may have remained quiet. As a result, some patients have suffered unnecessarily from serious treatment-related side effects, such as erectile dysfunction or incontinence.
The task force's recommendation caused some confusion. A panel of experts from the American Society of Clinical Oncology then decided that general PSA screening should be discouraged for men with a life expectancy of less than 10 years. For others, the panel said, the test should be discussed on a case-by-case basis to see if it is appropriate for them.
Messing and Emelian Scosyrev, PhD, assistant professor of urology, 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.
In addition, Messing said that prostate cancer death rates have been reduced by close to 40 percent. This occurred without substantial changes in how men were treated (via surgery and radiation therapy). Other research has suggested that more than 50 percent of this reduction is due to early detection.
That being said, it is important to remember that early diagnosis doesn't necessarily translate into better survival. The cancer may have already metastasized at the time of the screening, and it may remain undetected at that time, as well.
Should we be discouraging men with a life expectancy of less than 10 years from getting the PSA test? If so, how does one predict life expectancy?