Type 2 diabetes linked to increased risk of cancer

Type 2 diabetes increases the risk of developing many diseases, including various types of cancer; however, the mechanisms responsible for this association remain unclear.

A recent study published in BMC Medicine examines the risk of cancer in diabetics.

Type 2 diabetes is a metabolic disease caused by both genetic and environmental factors. Large epidemiological studies have shown that people with diabetes have a higher risk of developing cancers of the liver, pancreas, uterus, colon, rectum, breast and bladder.

Diabetes is associated with microvascular diseases, the most common manifestation of which is diabetic retinopathy (DR), which is the leading cause of vision loss in middle age. Multiple factors, such as high blood sugar, high levels of toxic glycation products, and activation of several pathways common to cancer development, contribute to the development of diabetic retinopathy.

Common phenomena such as oxidative stress, inflammation, vascular abnormalities, and the formation of new blood vessels are common in both cancer and DR. Thus, better glycemic control may reduce the incidence of cancer in this population.

The overall incidence of cancer increased by 20% in patients with diabetes, with the greatest increases in risk for liver and pancreatic cancers, followed by cancers of the oral cavity, gallbladder, female reproductive system, kidney and brain. This increase in risk ranged from 25 to 34%, with the exception of kidney cancer, where the risk was 44% higher.

Other cancers that moderately increased the risk by 17-20% included cancers of the stomach, skin and breast in women, and urinary tract cancer. The only cancer that decreased in the diabetic cohort was esophageal cancer.

Men with diabetes have a 20% increased risk of cancer. Patients with underlying hypertension had a 10% higher risk of cancer, while patients with high blood lipid levels had a 14% lower risk of overall cancer, but an increased risk of breast cancer in women.

The inverse association between hyperlipidemia and cancer may be associated with an increased risk of early cardiovascular mortality; however, there may also be a direct anti-cancer effect of high cholesterol levels.

Patients with diabetes and diabetic retinopathy had a significantly higher overall incidence of cancer compared with the cohort without diabetic retinopathy - 32% and 20%, respectively. The incidence of liver, mesothelial, urinary tract and soft tissue cancers increased in the diabetes with diabetic retinopathy group.

Other sites with a moderately increased risk of cancer included the oral cavity, lip, stomach, colon, and pancreas. Cancers of the lymphatic system and bone marrow were also more common among patients with diabetes and diabetic retinopathy.

Among patients with diabetic retinopathy, the risk was 13% higher in those who had proliferative diabetic retinopathy (PDR) than in those who had nonproliferative diabetic retinopathy (NPDR). Stomach, liver, gynecological, and urinary tract cancers were more common in patients with PDR compared with patients with NPDR. Likewise, men had a 25% higher risk than women.

Diabetes is an independent and significant risk factor for the development of cancer in general, as well as cancer in specific locations. This risk is increased in people with diabetes who develop diabetic retinopathy, which may be due to significantly higher levels of vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2) in these patients compared to people with diabetes without diabetic retinopathy. Retinopathy.

Systemic inflammation, which is often a response to diabetes, can also increase the risk of various types of cancer, including liver, pancreatic, colon and breast cancer. In addition, numerous inflammatory mediators, including proinflammatory cytokines and chemokines, are released in diabetic retinopathy, which may also contribute to carcinogenesis.

These results raise the possibility that diabetes and diabetic retinopathy may share pathogenetic features with cancer, and strict control of blood glucose levels to prevent diabetic retinopathy in patients with diabetes may further reduce the development of cancer.