The prostate-specific antigen (PSA) test is used to screen for prostate cancer; however, some task forces advocate abandoning its use because it leads to unnecessary biopsies. Now, a Canadian study shows that a repeat PSA test in patients with abnormal findings can dramatically reduce the number of unnecessary biopsies. These findings are published in Mayo Clinic Proceedings (doi:10.1016/j.mayocp.2015.07.030)
In this study, Rodney Breau, MD, and Luke Lavallée, MD, at The Ottawa Hospital and the University of Ottawa in Canada, and colleagues investigated what impact prompt repeat PSA test would have on the number of men referred for biopsy. Their study involved 1268 men undergoing prostate cancer screening.
“A high PSA level is associated with a greater risk of prostate cancer, and PSA screening can help detect cancer at an earlier, more treatable stage,” explained Breau, a prostate cancer surgeon and associate scientist in epidemiology.
However, fluctuations in PSA levels can be caused by infections, physical activity, and laboratory error. To accommodate this variation, the researchers implemented a protocol in which all abnormal (high) PSA test results prompted a repeat test before referring the patient for a biopsy. “We had a hunch that this would reduce unnecessary biopsies, and our study shows that our suspicion was correct,” said Breau.
The researchers reviewed the medical records of 1268 men evaluated at the Ottawa Regional Cancer Assessment Centre between 2008 and 2013 and whose PSA test results were high. In 25% of the men, results of the second PSA test were normal. Only 28% of the men with conflicting test results underwent a biopsy compared with 62% of men whose test results were abnormal in 2 tests. This represents a 55% reduction in biopsies.
Furthermore, only 3% of men with conflicting test results who underwent biopsy received a cancer diagnosis within the year, compared with 19% of men with two abnormal test results. This suggests that the second test result is important.
“It is clear to me that any man with an abnormal PSA test should have this test repeated before a decision to biopsy,” concluded Breau.
Some doctors and patients may worry about missing a significant cancer diagnosis if they forgo biopsy after conflicting test results. “But our study shows this is very unlikely,” explained Breau. The PSA test is just 1 factor considered when making the decision to proceed to biopsy, which always involves the patient in the decision making and can be revisited if risk factors change.
“Our study has important implications for patients and the health care system,” said Lavallée, a prostate cancer surgeon and researcher. “Prostate biopsies can be uncomfortable and inconvenient for patients, and in rare cases, they can lead to infections, so we only want to do these if they are really necessary. Prostate biopsies are also expensive for the health care system.”
Approximate costs are $30 for a PSA test but $880 for a prostate biopsy.