Link between diabetes and cancer
Diabetes has been shown to be associated with an increased risk of several cancers, but these associations are not documented as causal. The evidence for specific diabetes drugs affecting cancer risk is limited, because randomised clinical trials are not designed to evaluate cancer-specific outcomes. The overall goal of the EU-funded 'The association between type 2 diabetes diagnosis and diabetes medications with risk of cancer' (DIABETES AND CANCER) project was to evaluate the link between T2d diagnosis and T2d treatment with cancer risk. Critical assessment of the literature of T2d and cancer risk included 26 meta-analyses associating diabetes with 26 different cancer sites. Substantial heterogeneity was present in the majority of these meta-analyses. An excess of statistically significant results was observed only in 5 meta-analyses (liver, bladder, kidney cancer, non-Hodgkin's lymphoma and multiple myeloma). This evaluation suggests that largely T2d is a consistent risk factor for the development of several cancers. Researchers evaluated the association of T2d with the risk of prostate cancer in a large European cohort. Among 139 131 eligible men, 4 531 were diagnosed with prostate cancer over an average follow-up of 12 years. Compared to men with no diabetes, men with diabetes had a 26 % lower risk of prostate cancer. There was no evidence that the association differed by stage or grade of the disease. Finally, the association between anti-diabetic medications (sulfonylurea and metformin) and cancer risk was evaluated in a large retrospective cohort study. No evidence was found of an association for cancers of the colorectum, prostate, lung, postmenopausal breast cancer or any other cancers. Project activities will have major impact in the field. The literature on the association of diabetes diagnosis and treatment and cancer risk was finally properly evaluated. Identified associations may be further assessed in the prospective studies.
Keywords
Type 2 diabetes, cancer, clinical trials, treatment, prostate cancer, meta-analyses
