Biomarkers are "chemicals" that can indicate both normal and abnormal processes in the body. One of the most famous is prostate-specific antigen (PSA). The PSA test, which detects abnormally high blood levels of PSA, has been used for decades to screen for prostate cancer and potentially catch it early.
There are two problems with the PSA test. First, PSA levels can tell you that something is going on with the prostate — but that "something" isn't necessarily cancer. High levels may mean other benign prostate conditions. Second, when high PSA levels do turn out to be the result of prostate cancer, the PSA level alone won't tell you which cancers are aggressive and need treatment, and which are slow-growing and can be managed more conservatively.
Fortunately, rapid advances in analytical methods are identifying potentially new and better biomarkers to test for prostate cancer. If successful, they could transform how prostate cancer is detected, diagnosed, and treated. Here's a quick list of some of the most promising options:
Urine-based biomarkers. The prostate sheds material that can be detected and measured in the urine. New urine tests can detect changes in genes and biomarkers that are specific to prostate cancer. The results of these new tests can help pinpoint whether a biopsy is necessary.
Genetic tests of prostate tissue. Newer and more sophisticated tests that look for markers of specific genes can help doctors distinguish between slow-growing and more aggressive forms of prostate cancer. These tests can even detect hidden cancers in men whose biopsies were negative.
Circulating tumor cells. Cancer spreads when tumor cells break away, get swept up into the bloodstream, and start to grow in other parts of the body. A new "liquid biopsy" uses a simple blood test to capture and measure circulating tumor cells and their corresponding telltale markers. While this test isn't readily available yet, it could someday reduce the need for follow-up biopsies and help determine when prostate cancer treatment is working.
For more on advances in the diagnosis and treatment of prostate cancer, including more details on the latest advances in biomarkers, buy the Annual Report on Prostate Diseases from Harvard Medical School.