Circulating Free Insulin-Like Growth Factor (IGF)-I , Total IGF-I, and IGF Binding Protein-3 Levels Do Not Predict the Future Risk to Develop Prostate Cancer: Results of a Case-Control Study Involving 201 Patients within a Population-Based Screening with a 4-Year Interval

Recent studies have reported that serum IGF-I levels in the highest quartile of the normal range and IGF binding protein-3 (IGFBP-3) in the lowest quartile of the normal range are associated with an increased risk of future prostate cancer and/or presence of prostate cancer. It has also been suggested that the measurement of circulating total IGF-I concentrations might be a useful tool for the early detection of prostate cancer in men with moderately increased prostate-specific antigen (PSA) levels. To determine whether circulating free IGF-I, total IGF-I, and IGFBP-3 levels can predict future prostate cancer risk, we prospectively studied prostate cancer characteristics in a cohort of men during two rounds (mean interval, 4 yr) of a population-based screening study for prostate cancer. Two hundred one prostate cancer cases were detected at the second-round screening (aged 55–70 yr), and all these subjects were enrolled in the case group for the present study. Prostate cancer had been confirmed by biopsy ...