New Prostate Cancer Screening Algorithm Proposed

Investigators have proposed a new approach to prostate cancer (PCa) screening in which a PSA level of 1.5 ng/mL or higher should prompt primary care physicians—who order most PSA screening tests—to consider referring patients to a urologist for further evaluation. Men who have a PSA below 1.5 ng/mL would have a routine follow-up PSA test in 5 years.

“In our algorithm, we recommend that a biopsy should not be performed unless the risk of an aggressive tumor is significant, and following a thorough discussion of benefits and risks with the patient,” the investigators, led by E. David Crawford, MD, of the University of Colorado, Denver, wrote in Urology (2016;96:116-120). “These discussions should emphasize that the purpose of screening is the early identification of potentially lethal disease, and that in most cases low-risk tumors, if identified, do not require immediate treatment.”

Under their proposed new approach, primary care physicians (PCPs) would refer to urologists those patients who have a PSA level of 1.5 ng/mL or higher or abnormal digital rectal examination (DRE) results. Urologists then would explore possible causes for elevated PSA or abnormal DRE results, including PCa, benign prostatic hyperplasia, and prostatitis. For patients suspected of having PCa, urologists would consider ordering genomic tests such as the Prostate Health Index, 4Kscore, or SelectMDx assays. Patients deemed to be at high risk for aggressive cancer would be considered for transrectal ultrasound-guided prostate biopsy. Patients at low risk for aggressive cancer would be referred to their PCPs for repeat PSA testing in 1 year.

This algorithm is similar to that used for an elevated blood sugar, where an abnormal result triggers another test, such as an A1C hemoglobin test, the investigators stated.

PCPs, who order approximately 90% of PSA screening tests, are confused about the messages they receive regarding PSA, Dr Crawford's group stated. “We believe that a simple message using a PSA cutoff of 1.5 ng/mL is reflective of what PCPs often experience with conditions such as mild hypertension and prediabetes,” they wrote. “In this paper, we have presented an alternative approach in which screening is performed for men with at least a 10-year life expectancy.”

Previous research has shown that men with a PSA level of 1.5 ng/mL or higher at a younger age are at increased risk for the development of any PCa and significant PCa later in life. Dr Crawford's group cited a study by Hans Lilja, MD, and colleagues published in Cancer(2011;117:1210-1219) showing that approximately 5% of men who had a PSA value of 1.5 ng/mL or higher when blood was drawn at ages 44 to 50 years will be found to have advanced PCa  20 to 25 years later.

The investigators also reported data from BioReference Laboratories, Inc., showing that approximately 30% of men aged 45 to 70 years have a PSA level of 1.5 ng/mL or above.

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