The effect of oral glucose tolerance test on insulin and some related indicators in eldery male patients with prostate cancer and benign prostat hyperplasia

Introduction: Insulin, insulin like growth factor-1 and insulin like growth factor binding protein- 3 were associated with prostate cancer. The aim of our study was to define the relationship between insulin like growth factor-1 and insulin like growth factor binding protein-3 serum levels, and correlate these proteins with the oral glucose tolerance test. Materials and Method: Eighty-four male patients who had undergone prostate biopsy were included in the retrospective study. Oral Glucose Tolerance Test was done. Fasting, 1-hour and 2-hour plasma samples were used to measure serum levels of insulin, insulin like growth factor- 1 and insulin like growth factor binding protein-3. The patients were divided into two groups: Benign and Malign. Results: The mean age was 64.5±0.91 years. There was a significant difference between benign and malign groups in prostate specific antigen levels—6.14±0.7 ng/ml, and 11.6±2.2 ng/ml (p=0.001). The mean insulin level for 2 hour in malign group was significantly lower than that of benign group (81.9±12 μIU/ml and 57.4±17.2 μIU/ml (p=0.033). Insuline like growth factor binding protein-3 levels after glucose tolerance test were 4725.9±504.4 ng/ml and 3929.4±346.5 ng/ml for 1 hour and 2 hours, respectively, and significantly lower in benign group (p=0.046). Conclusion: Insulin, insulin like growth factor-1 and insulin like growth factor binding protein- 3 remain far away as being defined as tumor markers for prostate cancer since findings are still inconclusive and unclear. Future studies on the their axis and its genetics are obviously needed to understand if there is any role of these substances in the development of prostate cancer.