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Suspected clinically localised prostate cancer — MSRA MCQ

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HardPI-RADSSuspected clinically localised prostate cancerMSRA

A 61-year-old man is investigated on the suspected prostate cancer pathway. He would be suitable for radical treatment if clinically significant prostate cancer were diagnosed. His PSA is 5.2 micrograms/L, MRI-derived prostate volume is 65 mL (PSA density 0.08 ng/mL/mL), digital rectal examination is benign, and he has not previously had a prostate biopsy. Multiparametric MRI demonstrates a 10 mm focal lesion in the left posterolateral peripheral zone. It is focally mildly hypointense on the ADC map and focally mildly hyperintense on high-b-value diffusion-weighted imaging, consistent with a DWI score of 3. T2-weighted imaging shows no definite focal mass. Dynamic contrast-enhanced imaging shows no focal early enhancement corresponding to the abnormality. There is no extracapsular extension. Which PI-RADS v2.1 interpretation and immediate diagnostic management is most appropriate?

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Correct answer: D — PI-RADS 3; offer an MRI-influenced prostate biopsy

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

This is a peripheral-zone lesion, where DWI/ADC is the dominant PI-RADS sequence. The focal but only mild diffusion abnormality is DWI score 3, so the lesion is initially equivocal. In the peripheral zone, positive dynamic contrast enhancement may upgrade a DWI-score-3 lesion to PI-RADS 4; however, DCE is negative here, so the final PI-RADS category remains 3. Absence of extracapsular extension also provides no basis for a higher category. Despite the low PSA density (0.08 ng/mL/mL), NICE recommends MRI-influenced biopsy for an MRI Likert score of 3 or more. In a UK diagnostic pathway, the corresponding equivocal MRI finding should therefore prompt biopsy rather than PSA surveillance alone in this man who is fit for radical treatment. B incorrectly upgrades the lesion despite absent focal early enhancement. C is tempting because low PSA density lowers the probability of clinically significant cancer, but it does not override NICE's recommendation to offer biopsy for MRI scores of 3 or more. D incorrectly downgrades an equivocal focal DWI lesion to PI-RADS 2. E combines an incorrect low PI-RADS category with a biopsy strategy that is not the appropriate MRI-influenced approach for this MRI-visible lesion.

Reference: NICE NG131: Prostate cancer: diagnosis and management — MRI and biopsy recommendations (Updated March 2026) — https://www.nice.org.uk/guidance/ng131/chapter/Recommendations Prostate imaging reporting and data system version 2 (PI-RADS v2): a pictorial review (2016) — https://pubmed.ncbi.nlm.nih.gov/27522352/ Investigating the role of DCE-MRI, over T2 and DWI, in accurate PI-RADS v2 assessment of clinically significant peripheral zone prostate lesions (2018) — https://pubmed.ncbi.nlm.nih.gov/30361870/