IS VISCERAL ADIPOSITY INDEX (VAI)RELATED TO PROSTATE CANCER DETECTED BY BIOPSY?

Abstract

association between obesity and prostate cancer, yielding inconsistent results. Metabolic syndrome has been suggested to promote aggressive prostate tumors. In a previous study we failed to detect a relation between Body Mass Index (BMI) and prostate cancer Gleason score (1). BMI, although routinely adopted to measure obesity, has low sensitivity and specificity. A novel sex-specific obesity index, based on waist circumference (WC), BMI, triglycerides (TGs) and high density lipoproteins (HDL), the Visceral Adiposity Index (VAI), has been proposed to estimate the visceral adiposity dysfunction (2). The aim of our preliminary research was to correlate VAI and BMI with the presence of prostate cancer and the Gleason score at biopsy. Patients and Methods: Patients, undergoing prostate biopsy for palpable prostate nodule and/or elevated PSA levels, entered the study. After informed consent a transrectal prostate biopsy, 12 cores at least, was performed. The number of cores increased in rebiopsies (18-24 cores). A database including clinical, biochemical and pathological data was created. Prostate cancer detection at biopsy, Gleason score (6 or less versus 7 or higher), VAI, BMI and PSA values were statistically analyzed with Wilcoxon rank sum test. Results: Fifty-one patients were evaluated. The median age was 66 years (range 47-80). Two patients (3.9%) had a previous negative biopsy. The median BMI was 27.7 kg/m2 (range 18.7-40) and the median VAI was 4.4 (range: 1.6-15.6). Median PSA was 8.5 ng/ml (range 3.2- 53). A prostate nodule was palpable in 9 (17.6%) patients. The median prostate volume was 48 cc (range: 14-106). A prostate cancer was detected in 24 (47%) patients, with a Gleason pattern 6 in 14 (58.3%) patients and 7 or higher in the remaining 10 (41.7%). Among patients with positive prostate biopsy, median PSA BMI and VAI were 10.2 ng/ml, 27.8 Kg/m2 and 5.8, respectively. Among patients with negative prostate biopsy, median PSA BMI and VAI were 7.0 ng/ml, 26.8 Kg/m2 and 5.5, respectively. Only PSA levels were slightly related to biopsy positivity (p-value=0.08), no difference was detected for VAI (p-value=0.89) and BMI (pvalue= 0.19). Median PSA, BMI and VAI resulted 9.2 ng/ml, 27.8 Kg/m2 and 5.6, respectively in patients with Gleason score of 6 or less, and 10.9 ng/ml, 27.7 Kg/m2 and 5.8, respectively, in patients with Gleason score >6. Even in this case PSA levels were slightly related to prostate cancer aggressiveness (p-value=0.12), while no difference was highlighted for VAI (p-value=0.6665) and BMI (pvalue= 0.6394). Discussion and Conclusion: The identification of patients harboring an aggressive prostate cancer remains an important goal. The contradictory results on the relation between obesity and prostate cancer could be due to the low accuracy of BMI as a marker of metabolic syndrome. VAI has been recommended as an accurate indicator of adipose tissue activity. Nevertheless, our preliminary results do not detect any significant correlation between VAI, BMI, positivity of prostate biopsy and Gleason score