Leptin plasma levels in patients undergoing prostate biopsy. a preliminary study in 50 patients

Introduction/Aim: To reduce the number of negative prostate biopsies and to detect clinical significant prostate tumors in patients with elevated serum PSA represent major challenges in urological oncology. Prostate tumors diagnosed in patients with elevated Body Mass Index (BMI) show higher Gleason score and more aggressive biological behavior than those diagnosed in normal population (1). Elevated plasma levels of leptin and other adipose tissue derived factors (adipokines), are evident in obese men (2). Many studies have investigated the role of leptin as a putative molecular mediator between obesity and prostate cancer with contradictory results. Also in normal or overweight (BMI <30) men, leptin might represent a marker of tumor aggressiveness (3) and a useful tool in selecting patients undergoing prostate biopsy. Patients and Methods: Unselected patients ndergoing prostate biopsy for palpable prostate nodule and/or elevated PSA levels were entered in the study. A cut-off PSA level of 4 ng/ml was adopted. The plasma levels of leptin were measured by BioPlex immunoassay in 50 patients undergoing prostate biopsy. A 12-core transrectal biopsy was planned. The serum leptin levels were related with the results of the biopsy and the PSA levels. ROC curve analysis was exploited to test the diagnostic accuracy of leptin and PSA by AUC calculation. A potential cut-off level was computed. Results: Leptin was evaluated in 50 patients, 15 (30%) after a previous negative biopsy. The median PSA was 6.8 ng/ml. A prostate nodule was palpable in 18 (36%) patients. The median prostate volume was 45 cc. The median number of biopsy cores was 12. Prostate cancer was detected in 25 (50%) and ASAP and PIN in 2 (4%) more patients respectively. At a cut-off value of 2.16 ng/ml, leptin demonstrates a sensitivity of 74% and a specificity of 75%. Sixteen patients (32%) had negative leptin and negative prostate biopsy in spite of elevated PSA and/or palpable nodule. Discussion and Conclusion: Leptin in our preliminary experience shows promising diagnostic accuracy for the selection of patients candidate to prostate biopsy. Further and larger studies are needed to confirm our results. Adiponectin should be considered in further research. References 1 Discacciati A, Orsini N and Wolk A: Body mass index and incidence of localized and advanced prostate cancer – a dose-response meta-analysis of prospective studies. Ann Oncol 23: 1665-1671, 2012. 2 Adamczak M and Wiecek A: The adipose tissue as an endocrine organ. Semin Nephrol 33(1): 2-13, 2013. 3 López Fontana CM, Maselli ME, Pérez Elizalde RF, di Milta Mónaco NA, Uvilla Recupero AL and López Laur JD: Leptin increases prostate cancer aggressiveness. J Physiol Biochem 67(4): 531-538, 2011.