MRI-targeted versus systematic needle core biopsies in prostate cancer: a patient-based analysis of potential diagnostic and biologic underestimation

AIMS: MRI-targeted needle core biopsy (MRI-NCB) improves detection of clinically significant prostate cancer (csPCa), but whether it can replace systematic ultrasound-guided biopsy (US-NCB) remains debated, as most studies have focused on cancer detection and grade. METHODS: We retrospectively analysed 562 patients with PI-RADS 3-5 lesions who underwent both MRI-NCB and concurrent US-NCB. Outcomes included cancer detection, Grade Group (GG) and adverse features (cribriform morphology and intraductal carcinoma (IDCP)). csPCa was defined as GG ≥2. A composite endpoint of clinically meaningful under-detection or underestimation was defined as missed or under-graded csPCa and/or missed adverse histological features on MRI-NCB relative to US-NCB. RESULTS: MRI-NCB alone would have missed PCa in 13.0% (73/562) of patients, including csPCa in 11.4% (64/562) and would have underestimated GG in 13.3% (75/562). Systematic biopsy identified additional cribriform morphology in 4.3% (24/562) and IDCP in 2.5% (14/562) of patients not detected on MRI-NCB. Overall, MRI-NCB alone would have resulted in clinically meaningful under-detection or underestimation in 16.4% (92/562). Of these, 63.0% had missed or under-graded csPCa only, 30.4% had missed adverse histologic features only and 6.5% had both. Missed cancers were more frequent in lower PI-RADS lesions whereas upgrading was more common in higher PI-RADS lesions. Incremental detection of IDCP was significantly higher in PI-RADS 5 compared with PI-RADS 4 lesions (adjusted p=0.048). CONCLUSIONS: MRI-targeted biopsy alone may incompletely assess cancer detection and tumour biology. Systematic biopsy provides complementary diagnostic value, and omission may result in clinically meaningful under-detection or underestimation, even in high PI-RADS lesions.