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Suspected localised prostate cancer — MSRA MCQ

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ModeratePI-RADSSuspected 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 7.2 micrograms/L, MRI-derived prostate volume is 48 mL and DRE is benign. Multiparametric MRI identifies a 16 mm non-circumscribed, homogeneous, moderately T2-hypointense lesion in the anterior transition zone. It is markedly hypointense on ADC and markedly hyperintense on high-b-value DWI. There is no focal early enhancement on dynamic contrast-enhanced imaging and no extracapsular extension. 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: B — Classify the lesion as PI-RADS v2.1 category 5 and arrange an MRI-influenced prostate biopsy

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

This is a transition-zone lesion, for which T2-weighted imaging is the dominant PI-RADS sequence. The lesion is non-circumscribed and homogeneously moderately T2-hypointense, with marked diffusion restriction. Its greatest diameter is 16 mm, exceeding the 1.5 cm threshold for PI-RADS v2.1 category 5. Absence of focal early enhancement does not downgrade a transition-zone lesion: DCE is not the determining sequence in this setting. Lack of extracapsular extension also does not prevent category 5 classification when the size criterion is met. In UK practice, NICE recommends multiparametric MRI as the first-line investigation for suspected localised prostate cancer and MRI-influenced biopsy for MRI findings reported as Likert 3 or above. A lesion with these high-suspicion features should therefore proceed to MRI-influenced biopsy. B is attractive because marked diffusion restriction in a sub-1.5 cm transition-zone lesion would support category 4, but this lesion is 16 mm. C wrongly substitutes PSA surveillance for tissue diagnosis despite a high-suspicion MRI lesion. D undercalls the lesion; category 3 would be considered for an equivocal transition-zone lesion rather than one meeting the size and morphological criteria for category 5. E combines an incorrect category with systematic-only biopsy rather than MRI-influenced sampling.

Reference: NICE NG131: Prostate cancer: diagnosis and management — MRI and biopsy recommendations (2019; current page checked August 2026) — https://www.nice.org.uk/guidance/ng131/chapter/recommendations PI-RADS v2.1 for the evaluation of transition zone lesions: a practical guide for radiologists (2021) — https://pubmed.ncbi.nlm.nih.gov/34919421/