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Suspected clinically localised prostate cancer — MSRA MCQ

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ModeratePI-RADSSuspected clinically localised prostate cancerMSRA

A 64-year-old man is investigated on the suspected prostate cancer pathway. He would be suitable for radical treatment if clinically significant prostate cancer is diagnosed. His PSA is 7.4 micrograms/L, MRI-derived prostate volume is 50 mL, and digital rectal examination is benign. Multiparametric MRI shows a 17 mm focal lesion in the left peripheral zone. It is markedly hypointense on the ADC map and markedly hyperintense on high-b-value diffusion-weighted imaging. There is no definite extracapsular extension. Dynamic contrast-enhanced imaging shows no focal early enhancement. The radiologist records an overall Likert score of 5. Which reporting interpretation and immediate diagnostic management is most appropriate?

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

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Correct answer: D — Classify the lesion as PI-RADS 5 and arrange an MRI-influenced prostate biopsy

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

The correct answer is A. In the peripheral zone, diffusion-weighted imaging is the dominant PI-RADS sequence. A focal lesion with marked diffusion restriction is scored PI-RADS 4 when it is under 1.5 cm; a lesion greater than 1.5 cm is PI-RADS 5, even without definite extracapsular extension. This 17 mm lesion therefore meets PI-RADS 5 criteria. Negative dynamic contrast enhancement does not downgrade a peripheral-zone lesion that is already highly suspicious on DWI. In UK practice, NICE recommends MRI-influenced prostate biopsy for an MRI Likert score of 3 or more. His Likert 5 result, fitness for radical treatment and targetable lesion therefore support prompt MRI-influenced biopsy. B is attractive because marked diffusion restriction alone commonly denotes PI-RADS 4, but it misses the decisive 1.5 cm size threshold. C incorrectly treats negative DCE as making the lesion equivocal; DCE chiefly resolves peripheral-zone DWI score-3 lesions. D gives the correct radiological category but inappropriately substitutes surveillance for biopsy despite a high-suspicion MRI. E would be relevant only for a low-risk MRI result, generally Likert 1 or 2, after shared decision-making.

Reference: NICE NG131: Prostate cancer: diagnosis and management — MRI and biopsy recommendations (2019; current webpage checked 15 August 2026) — https://www.nice.org.uk/guidance/ng131/chapter/recommendations PI-RADS v2.1: What has changed and how to report (2021) — https://pubmed.ncbi.nlm.nih.gov/34230862/