Lesion size on prostate magnetic resonance imaging predicts adverse radical prostatectomy pathology.

OBJECTIVES: To investigate the value of the maximal lesion diameter on preoperative multiparametric/bi-parametric magnetic resonance imaging for estimating the risk of adverse radical prostatectomy pathology. PATIENTS AND METHODS: Consecutive patients (n = 162) with prostate multiparametric or biparametric magnetic resonance images acquired before prostatectomy were retrospectively stratified into two groups: 65 patients with normal MRI (n = 18) or a suspicious lesion <15 mm in diameter (n = 47), and 97 patients with a lesion diameter ≥15 mm. The presence of extraprostatic extension, margin positivity, seminal vesicle invasion, and lymph node metastasis was examined in these groups using logistic regression analysis, including preoperative clinical parameters (prostate-specific antigen concentration, biopsy Gleason grade group, clinical T-stage, and D'Amico risk group). RESULTS: The prevalence of extraprostatic extension, margin positivity, and seminal vesicle invasion was 53.1% (86/162), 22.8% (37/162), and 17.9% (29/162), respectively. Lymphadenectomy was performed in 64 men, of whom 14 had lymph node metastasis. Lesion diameter ≥15 mm strongly predicted extraprostatic extension (Odds ratio: 7.94, 95% confidence interval: 3.87-16.28, p < 0.001), margin positivity (Odds ratio: 7.86, 95% confidence interval 2.63-23.51, p < 0.001), and seminal vesicle invasion (Odds ratio: 7.57, 95% confidence interval 2.18-26.22, p = 0.001). Lesion diameter ≥15 mm was an independent risk factor for adverse prostatectomy pathology. Lesion diameter ≥20 mm, but not ≥15 mm, was a significant risk factor for lymph node metastasis. CONCLUSION: Magnetic resonance imaging lesion diameter ≥15 mm is an independent risk factor for extraprostatic extension, margin positivity and seminal vesicle invasion.