One of the most well-known—and controversial—methods of cancer detection is the PSA test. PSA stands for prostate-specific antigen, the marker in blood that can indicate the presence of prostate cancer.
The PSA test was developed at Roswell Park Comprehensive Cancer Center in the 1970s and was initially intended to check for returning prostate cancer in men who had already undergone treatment. Later, many doctors began using it in healthy men to screen for an initial diagnosis. It has helped diagnose millions of men across the world and saved countless lives.
But in recent years, the usage of the PSA test has undergone scrutiny, with some saying it can lead to over diagnosis or unnecessary treatment. A recent study completed at Roswell Park is helping redefine how we use the PSA test by demonstrating that even when PSA is present, the levels of the marker can be a key indicator of what treatment is necessary—or unnecessary.
After a patient is diagnosed and his prostate is removed surgically, the PSA test is used to see if any cancer remains. About 30 percent of men in this situation will have detectable PSA in their blood. The standard course of treatment has been to have men with any detectable PSA undergo radiation therapy. However, for some men, radiation may not be needed.
Two-thirds of patients with detectable PSA after surgery have very low levels of the marker, and those levels rise slowly. Recently, we published results of a study at Roswell Park in the Journal of Urology that examined the PSA levels and survival rates of 2,500 prostate cancer patients. This study demonstrated that men with low, slowly rising PSA levels had almost identical survival rates to men who had no detectable PSA. Therefore, radiation therapy is unnecessary in most of these cases, and only adds the risk of undesired side effects.
For men who fall into this category of low-stable PSA, we advise using a program called active surveillance. Instead of undergoing radiation or other treatment, the PSA level of these patients would be monitored every six months for the first five years, and then yearly after that, to ensure PSA levels do not suddenly rise, indicating the return of cancer.
We believe that we could spare many men from dealing with the cost and side effects of radiation therapy in cases where this treatment is not necessary. The PSA test remains an important tool in diagnosing and managing prostate cancer, and we will continue to refine and explore how we can best use that tool for the benefit of patients.
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