Serum insulin‐like growth factor‐1 is not a useful marker of prostate cancer

Abstract

OBJECTIVE: To determine whether the use of serum insulin-like growth factor 1 (IGF-1) levels is more efficient than serum prostate specific antigen (PSA) levels in predicting prostate cancer in patients undergoing prostatic biopsy. PATIENTS AND METHODS: The study included 94 consecutive patients who required transrectal ultrasonography (TRUS)-guided biopsies of their prostate and who had blood samples taken before their biopsies. These samples were then analysed for IGF-1 and PSA concentrations. Six prostatic biopsies were taken from each patient; they were assessed and a diagnosis made of prostate cancer or no malignancy. RESULTS: Thirty-seven patients were found to have prostate cancer and 57 had no evidence of malignancy. There was no statistical difference in serum IGF-1 levels between these groups. The PSA level and age of the patients differed significantly between the groups (both P<0.001). There was no correlation between IGF-1 and PSA levels, and even when the age difference in the groups was considered, there was still no significant relationship between IGF-1 levels and the incidence of prostate cancer. In patients with a PSA level of 4-20 microg/L there was no statistically significant difference in IGF-1 levels between the groups. CONCLUSION: Serum IGF-1 as a tumour marker does not help to predict patients with prostate cancer. PSA level and even age were better predictors of the presence of prostate cancer than were serum IGF-1 levels.