Development of a Nomogram Incorporating Multiparametric MRI and Clinical Indicators for Predicting Positive Surgical Margins After Radical Prostatectomy.

BACKGROUND

This study aimed to develop a nomogram integrating multiparametric magnetic resonance imaging (mpMRI) features and clinical indicators for the preoperative prediction of positive surgical margins (PSM) after radical prostatectomy (RP).

METHODS

This retrospective study enrolled 304 patients who underwent RP for prostate cancer (PCa). The patients were divided into PSM (n = 98) and negative surgical margin (NSM, n = 206) groups based on histopathological results. Preoperative clinical variables, including prostate-specific antigen (PSA), PSA density (PSAD), biopsy Gleason Grade Group and clinical T-stage, were collected. The mpMRI parameters assessed included Prostate Imaging Reporting and Data System (PI-RADS) v2.1 score, tumour location, extracapsular extension (ECE), tumour maximum diameter, capsule contact length (CCL) and apparent diffusion coefficient (ADC) value.

RESULTS

Compared with the NSM group, the PSM group had significantly higher preoperative PSA, higher PSAD, a higher proportion of biopsy Gleason Grade Group 4-5, and a higher clinical T-stage proportion. On mpMRI, the PSM group exhibited a higher proportion of PI-RADS v2.1 score 5 lesions, more frequent transition zone tumours, higher suspicion of ECE, larger tumour maximum diameter, longer CCL and lower ADC value. Multivariate analysis identified PSAD, PI-RADS v2.1 score, suspected ECE, tumour maximum diameter, CCL, ADC value, and biopsy Gleason Grade Group as independent predictors of PSM (all p < 0.05). The nomogram achieved an area under the curve of 0.907 (95% confidence interval (CI): 0.873-0.941).

CONCLUSIONS

A nomogram combining mpMRI and clinical indicators may aid preoperative prediction of PSM after RP, potentially facilitating patient risk stratification.