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

Abstract

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. 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. 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. 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.