RESUMO
OBJECTIVE: To evaluate the relationship between circulating levels of insulin-like growth factor-1 (IGF-1), IGF-binding protein-3 (IGFBP-3) and colorectal cancer. METHODS: A meta-analysis of 6 epidemiological studies on insulin-like growth factors and risk of colorectal cancer were performed. RESULTS: The pooled odds ratio (OR) of IGF-1 and IGFBP-3 were 1.56 (95% CI: 1.14-2.13) and 0.78 (95% CI: 0.43-1.44) respectively. According to the results from different measurements (enzyme-linked immunoabsorbent assay and immunoradiometric assay), the pooled OR were 1.92 and 1.23 for IGF-1, 0.46 and 1.44 for IGFBP-3 respectively. CONCLUSION: High serum levels of IGF-1 were independent risk factors of colorectal cancer but the OR of IGFBP-3 was not statistically significant. The heterogeneity between studies on IGFBP-3 and colorectal cancer was caused by different measurements used, but there was still a need to conduct simultaneous large size study under 2 different measurements for further conclusion.
