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Possible prostate cancer in a man taking finasteride for benign prostatic hyperplasia — MSRA MCQ

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HardUrologyPossible prostate cancer in a man taking finasteride for benign prostatic hyperplasiaMSRA

A 66-year-old man attends for review of lower urinary tract symptoms. He has taken finasteride 5 mg daily and tamsulosin for 18 months for a 48 g benign-feeling prostate. He reports good adherence and his voiding symptoms are stable. He has no dysuria, fever, recent urinary instrumentation or symptoms of urinary tract infection. Digital rectal examination remains benign. His PSA was 3.4 micrograms/L before starting finasteride, 1.5 micrograms/L after 6 months, and is now 2.8 micrograms/L. What is the most appropriate next step?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: E — Make a suspected cancer pathway referral for prostate cancer while continuing current treatment

Explanation lettering: C = shown as A · A = shown as C

Finasteride lowers PSA by approximately 50%; after at least 6 months of treatment, the measured PSA should therefore be doubled when compared with usual PSA thresholds. This man's PSA of 2.8 micrograms/L represents an adjusted value of approximately 5.6 micrograms/L. At age 66, this exceeds the NICE age-specific threshold of 4.5 micrograms/L for a suspected cancer pathway referral in a person with possible prostate-cancer symptoms. The rise is also clinically concerning because his PSA has increased substantially from his post-finasteride nadir (1.5 to 2.8 micrograms/L) despite reported adherence. A benign DRE does not exclude prostate cancer and should not override the adjusted PSA result. Finasteride should not be stopped merely to interpret PSA; it can be adjusted for, and discontinuation would delay assessment. A is inappropriate because the adjusted PSA already meets the referral threshold. B is unnecessary and risks delay. C treats presumed BPH progression despite stable symptoms and fails to investigate a potentially malignant PSA pattern. D may eventually result in assessment, but a routine referral does not provide the urgency indicated by the suspected-cancer criteria.

Reference: NICE NG12: Suspected cancer: recognition and referral — prostate cancer recommendations (2021) — https://www.nice.org.uk/guidance/ng12/chapter/recommendations-organised-by-site-of-cancer Finasteride 5 mg film-coated tablets — Summary of Product Characteristics (17 September 2025) — https://www.medicines.org.uk/emc/product/13543/smpc