[Colorectal cancer and diabetes].

Colorectal carcinoma is a tumour with higher incidence in patients with type 2 diabetes and obesity. Recently, a slightly higher risk has also been shown in prediabetic states. The most important latest finding is that of a reduced risk in patients treated with metformin; there is a trend now to also prescribe metformin in patients with disturbed glucose tolerance or increased fasting glycaemia. Regular physical activity and reduced animal fat intake with increased intake of fruits and vegetables may help to prevent the disease. Pathogenesis may include changes to intestinal flora. The most important current preventive clinical measure is colonoscopy. Type 2 diabetes patients should be considered as a risk group and thus prevention should be targeted at these patients.