Periprostatic fat correlates with tumour aggressiveness in prostate cancer patients

Study Type – Prognostic (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? Nowadays more and more publications have been published about the topic prostate cancer aggressiveness and obesity with mixed results. However, most of the publications used the BMI as a marker for obesity, while the most metabolic active fat is the visceral fat. To learn more about these relations we measured and used the visceral fat in our paper. OBJECTIVE • To examine if the periprostatic fat measured on computed tomography (CT) correlates with advanced disease we examined patients who received radiotherapy for localized prostate cancer. Several USA reports found a positive association between obesity and prostate cancer aggressiveness. However, in recent European studies these conclusions were not confirmed. Studies concerning this issue have basically relied on body mass index (BMI), as a marker of general obesity. Visceral fat, however, is the most metabolically active and best measured on CT. PATIENTS AND METHODS • In 932 patients, who were treated with external radiotherapy (N= 311) or brachytherapy (N= 621) for their T1‐3N0M0 prostate cancer, different fat measurements (periprostatic fat, subcutaneous fat thickness) were performed on a CT. • Associations between the different fat measurements and risk of having high‐risk (according to Ash et al., PSA > 20 or Gleason score ≥8 or T3) disease was measured. RESULTS • The median age (IQR) was 67.0 years (62.0–71.0) and median BMI (IQR) was 25.8 (24.2–28.3). Logistic regression analyses, adjusted for age, revealed a significant association between periprostatic fat density (PFD) and risk of having a high risk disease. (Odds ratio [95% CI] 1.06 [1.04–1.08], P < 0.001) CONCLUSION • Patients with a higher PFD had more often aggressive prostate cancer.