Prostate Cancer Screening Improved by Repeating Abnormal Tests

By LabMedica International staff writers
Posted on 29 Dec 2015

Image: Micrograph from a prostate biopsy showing a prostatic adenocarcinoma, conventional (acinar) type, the most common form of prostate cancer (Photo courtesy of Nephron).

For more than 20 years, the prostate-specific antigen (PSA) test has been used to help screen for prostate cancer, but in recent years, some task forces have called for this blood test to be abandoned because it leads to many unnecessary biopsies.

Prostate-specific antigen may be elevated because of prostate cancer or as a result of infection, physical activity, or sexual activity. Variation in PSA concentrations can also be due to normal biological fluctuation or analytic and laboratory assay differences. As a result, PSA is sensitive but not specific for detecting prostate cancer, especially when levels are moderately elevated between 4 and 10 ng/mL.

Physicians and scientists at The Ottawa Hospital (ON, Canada) reviewed the medical records of 1,268 men who had an abnormal (high) PSA test result and were evaluated at the Ottawa Regional Cancer Assessment Centre between 2008 and 2013. In 25% of these men, the second PSA test came back normal. Only 28% of men with conflicting test results underwent a biopsy compared to 62% of men who had two abnormal test results, representing a 55% reduction in biopsies. In addition, only 3% of men with conflicting test results who had a biopsy were diagnosed with cancer within the year, compared to 19% of men who had two abnormal tests, suggesting that the second normal test is important. Repeated PSA test results were normal in 315 patients (24.8%).

Rodney H. Breau, MSc, MD, the senior author of the study said, “It is clear to me that any man with an abnormal PSA test should have this test repeated before a decision to biopsy. Some doctors and patients may be worried about missing a significant cancer diagnosis if they forgo a biopsy after conflicting test results, but our study shows this is very unlikely. It is also important to remember that the PSA test is just one factor we evaluate when deciding to do a biopsy, and these decisions are always made together with the patient, and can be revisited if risk factors change.” According to the Canadian Cancer Society, approximately 24,000 Canadians will be diagnosed with prostate cancer each year and the five-year survival rate is 96%. A PSA test costs approximately CAD 30, while a prostate biopsy costs approximately CAD 880.

The study was published on December 10, 2105, in the journal Mayo Clinic Proceedings.

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The Ottawa Hospital