The MKSAP Challenge
Answer: D
Educational objective: Manage abnormal PSA results.
Although not all experts recommend routinely checking serum PSA in men, the cut-off for abnormal values is 4.0 ng/mL. For those with an abnormal PSA, further evaluation by a urologist is appropriate. Although his value of 5.0 ng/mL is just the abnormal range, if the goal of screening is to find early prostate cancer, then values between 4 and 10 ng/mL deserve further testing.
When the PSA is greater then 10 ng/mL, the likelihood of locally or distally advanced prostate cancer (stage C or D) is much greater when compared to patients with a PSA from 4 to 10. The ability of the PSA test to discriminate between prostate cancer and benign causes of elevated PSA values is only fair, but the specificity of the test is better for men in their 50s when compared to men in their 70s. Tamsulosin is prescribed for men with benign prostatic hyperplasia, but this patient has no symptoms to suggest this disorder.
Population-based studies have suggested that a PSA increase of greater than 0.75 ng/mL per year is associated with prostate cancer. With a PSA level greater than 4 ng/mL, referral to a urologist would be preferred over further serial testing. Testing for free PSA would provide further risk information. However, even if this patient's free PSA is greater than 25%, studies suggest his risk of prostate cancer is still 8%. Most physicians would recommend urology evaluation. In areas of uncertainty such as this, patient preference plays a large role in decision-making.
References:
1. Harris R, Lohr KN. Screening for prostate cancer: an update of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med. 2002;137:917-29. PMID: 12458993.
2. Screening for prostate cancer: recommendation and rationale. U.S. Preventive Services Task Force. Ann Intern Med. 2002;137:915-6. PMID: 12458992.
More information about MKSAP 13 is online.
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