| [ Summary ] |
Emerging evidence from observational data and metaanalyses of the data suggest that diabetes mellitus is associated with an increased risk of cancer. Meta-analyses have indicated that diabetes increases the over all risk of cancer and of site-specific cancers of the breast, endometrium, bladder, liver, colorectum, and pancreas, and that it decreases the risk of prostate cancer. The combination of insulin resistance and secondary hyperinsulinemia is the most frequently proposed cause of cancer. Hyperglycemia alone may promote carcinogenesis. However, diabetes is associated with a higher risk for developing cancer in Asian men than in non-Asian men and the possibility of genetic component cannot be excluded. In addition to various facets of lifestyle including obesity, smoking, and lack of exercise, treatment for diabetes may affect the risk of cancer. For instance, metformin, an insulin sensitizer, reportedly has a potential anti-cancer effect. In light of the exploding global epidemic of diabetes, even a modest increase in cancer risk will translate into a substantial socioeconomic burden. Current insights into these disease relationships underscore the need for clinical attention and better-designed studies of the complex interactions between diabetes and cancer. |