Evaluation of MSKCC Preprostatectomy nomogram in men who undergo MRI-targeted prostate biopsy prior to radical prostatectomy

Abstract

Introduction: The Memorial Sloan Kettering Cancer Center (MSKCC) Preprostatectomy nomogram is a widely used resource that integrates clinical factors to predict the likelihood of adverse pathology at radical prostatectomy. Adoption of magnetic resonance imaging targeted biopsy (TB) permits optimized detection of clinically-significant cancer over systematic biopsy (SB) alone. We aim to evaluate the prognostic utility of the MSKCC Preprostatectomy nomogram with TB pathology results.

Methods: Men who underwent SB and magnetic resonance imaging TB who later underwent radical prostatectomy at our institution were included. Patient information was entered into the MSKCC Preprostatectomy nomogram using 5 biopsy reporting schemes with TB reported by both individual core (IC) and aggregate group (AG) methods. The likelihood of extraprostatic extension, seminal vesicle invasion, and lymph node involvement as predicted by the nomogram for each biopsy reporting schema were compared to radical prostatectomy pathology.

Results: We identified 63 men from January 2014 to November 2017. On receiver operating characteristic analysis, IC-TB, AG-TB, SB plus IC-TB, and SB plus AG-TB exhibited similar, if not improved, area under the curve compared to SB alone in predicting extraprostatic extension (0.671, 0.674, 0.658, and 0.6613 vs. 0.6085). This was similarly observed for seminal vesicle invasion prediction using SB plus IC-TB compared to SB alone (0.727 vs. 0.733). For lymph node involvement, superior but nonsignificant area under the curve was observed for AG-TB (0.647) compared to IC-TB (0.571) and SB alone (0.524) CONCLUSIONS: Using TB pathology results either alone or combined with SB pathology results as input to the MSKCC Preprostatectomy nomogram appears comparable for prognosticating adverse pathology on radical prostatectomy compared to SB alone, but robust validation is warranted prior to adoption into clinical practice.

Keywords: Fusion biopsy; Magnetic resonance imaging; Prostate cancer; Radical prostatectomy; Risk calculator.

Fig. 1.

Overview of biopsy acquisition and pathologic reporting schemas for a prostate with a single target (T) identified via mpMRI (A). Biopsy reporting consisted of systematic cores only (red, B), target cores only (white, C), or a combination (D). Target cores were then reported as individual cores (IC) or as aggregate groups (AG, E).

Fig. 2.

ROC curves for predicting (A) EPE, (B) SVI, and (C) LNI using various biopsy reporting schemas compared to final surgical pathology according to the MSKCC Preprostatectomy nomogram.