The detection rate of apical tumour involvement on preoperative MRI and its impact on clinical outcomes in patients with localized prostate cancer.

To determine the diagnostic performance of radiological apical tumour involvement (radATI) in preoperative prostate MRI, referenced to pathological ATI (pathATI) at radical prostatectomy specimens. To investigate risk factors for apical positive surgical margins (APSM). A retrospective cohort of consecutive patients with biopsy-proven PCa who underwent MRI and robot-assisted radical prostatectomy between July 2015 and March 2020 was studied (n = 177). Clinical, imaging, pathology, oncology and functional data were retrieved. The diagnostic accuracy of MRI to detect pathATI was analysed. Multivariate logistic regression was used to find independent predictors for APSM. radATI and pathATI was found in 121 (68%) and 161 (91%) patients, respectively. The diagnostic metrics of sensitivity, specificity, PPV, and NPV were 69, 38, 92, and 11%, respectively. APSM were present in 43 (24%) patients. Patients with radATI were more likely to have APSM (37/121 (31%)) than those without radATI (6/56 (11%)) (OR 3.67 [95% CI 1.45-9.31], p = 0.004). This was confirmed in multivariate analysis. Only 2/56 (4%) patients without radATI developed a biochemical recurrence compared to 25/120 (21%) patients with radATI (hazard ratio 6.68 [95% CI 3.03-14.8], p = 0.003). Prostate cancer extends into the apex in the majority of cases. Clinicians are advised to report on the presence or absence of radiological apical tumour involvement as it is an independent risk factor for apical positive surgical margins and is even associated with biochemical recurrence.