Periprostatic fat thickness quantified by preoperative magnetic resonance imaging is an independent risk factor for upstaging from cT1/2 to pT3 in robot-assisted radical prostatectomy.

ABSTRACT

OBJECTIVES: To analyze the correlation between periprostatic fat thickness on multiparametric magnetic resonance imaging and upstaging from cT1/2 to pT3 in robot-assisted radical prostatectomy. METHODS: We retrospectively evaluated data from men with cT1/2 prostate cancer treated with robot-assisted radical prostatectomy at Nara Prefecture General Medical Center, Nara, Japan, between March 2013 and December 2017. We calculated the periprostatic fat thickness and subcutaneous thickness from preoperative multiparametric magnetic resonance imaging. We divided the cohort into two groups for analysis. Group 1 included patients upstaged from clinical to pathological stage, whereas group 2 included those without upstaging. RESULTS: Data on 220 patients meeting the inclusion criteria were included in the analysis. A total of 36 patients were upstaged from clinical T1 or T2 to pathological T3, whereas 184 patients were not upstaged. The upstaging was associated with prostate volume, Gleason score, prostate-specific antigen density, periprostatic fat thickness, Prostate Imaging Reporting and Data System score based on univariate analysis. Multivariate analysis showed prostate volume (P = 0.03, odds ratio 0.958, 95% confidence interval 0.921-0.996), Gleason score (P = 0.022, odds ratio 2.676, 95% confidence interval 1.153-6.213) and periprostatic fat thickness (P = 0.004, odds ratio 1.26, 95% confidence interval 1.079-1.471) as independent risk factors of upstaging. CONCLUSIONS: Prostate volume, Gleason score and periprostatic fat thickness on multiparametric magnetic resonance imaging are significantly associated with and independent risk factors for upstaging from cT1/2 to pT3 in patients undergoing robot-assisted radical prostatectomy.