Periprostatic fat thickness on MRI: correlation with Gleason score in prostate cancer

The purpose of this study was to retrospectively evaluate the relationship between periprostatic fat thickness on MRI and Gleason score of prostate cancer using radical prostatectomy as the reference standard.

This study included 190 patients (mean age [± SD], 66.9 ± 7.0 years) who underwent MRI before radical prostatectomy. Two radiologists measured the subcutaneous and periprostatic fat thickness on midsagittal T2-weighted MR images as the shortest perpendicular distance from the pubic symphysis to the skin and prostate, respectively. Subcutaneous and periprostatic fat along with age, height, weight, body mass index, and prostate-specific antigen (PSA) were correlated with Gleason score by using Pearson (r) or Spearman (ρ) correlation coefficients and compared between low- (Gleason score = 6) and high- (≥ 7) grade prostate cancer by using univariate and multivariate logistic regression analyses.

The mean subcutaneous and periprostatic fat thicknesses were 24.0 ± 8.4 mm and 5.0 ± 2.0 mm, respectively. The Gleason score was significantly correlated with age (ρ = 0.181, p = 0.012), PSA (ρ = 0.345, p < 0.001), and periprostatic fat thickness (ρ = 0.228, p = 0.002). Multivariate analysis revealed that age, height, PSA level, and periprostatic fat thickness (odds ratio, 1.331; 95% CI, 1.063-1.666) were independently predictive of high-grade (p ≤ 0.013) disease.

Periprostatic fat thickness on MRI showed a mild to modest but significant correlation with Gleason score of prostate cancer with radical prostatectomy as the reference standard and was an independent predictive factor for high-grade prostate cancer.