Millions with type 2 diabetes ‘at greater risk of 3 killer cancers’, scientists discover

BRITS with type 2 diabetes may be at greater risk of breast, bowel and pancreatic cancers, a study suggests.

Genetic variants — differences in sequences of genes — affect a person’s risk of both diabetes and the three types of cancer, researchers found.

Experts said the research could help doctors identify people who have a higher chance of the conditions in future and tailor their treatment to their level of risk.

Dr Elizabeth Robertson, of Diabetes UK, said: “Type 2 diabetes and cancers are complex conditions with a multitude of factors increasing people’s likelihood of developing them.

“This research sheds new light on the role that genetically determined factors play in why some people with type 2 diabetes are also at risk of breast, colorectal and pancreatic cancer.”

More than five million Brits are thought to be living with diabetes, with cases doubling in the last 15 years.

Around 90 per cent of these have type 2 diabetes, which causes blood sugar levels to become too high because of problems with how the body produces the hormone insulin, which breaks down glucose.

In contrast, type 1 diabetes is a lifelong condition where the body’s immune system attacks and destroys the cells that produce insulin.

The NHS spends at least £10billion annually on diabetes — around 10 per cent of its entire budget.

Obese people have around a seven times greater risk of type 2 diabetes than those of a healthy weight.

But factors other than obesity like not getting enough exercise and genetics also play a role.

Hundreds of different genetic variants have already been identified as contributing to the condition, and it is known that genetics can also increase the risk of cancer.

However, the genetic factors that contribute to the link between type 2 diabetes and increased cancer risk have been poorly understood until now.

The latest study, presented at the Diabetes UK Professional Conference in London, looked at genetics to see if they could help to explain why some people with type 2 diabetes also get cancer.

Researchers focused on the three cancer types that people with type 2 diabetes are at higher risk of developing — post-menopausal breast cancer, bowel cancer and pancreatic cancer.

They used DNA data from more than 36,000 people, including people living with type 2 diabetes and cancer.

For the first time, they identified two specific genetic variants that are key contributors to people developing both type 2 diabetes and cancer.

In time, this could help doctors to identify people earlier who are at risk of both type 2 diabetes and certain cancers

Dr Elizabeth RobertsonDiabetes UK

One variant was linked to the risk of developing both breast cancer and type 2 diabetes, while the other affected type 2 diabetes and breast, bowel and pancreatic cancer risk.

People carrying either of these genetic variants will have an increased chance of developing both type 2 diabetes and these cancers, Professor Inga Prokopenko, of the University of Surrey said.

The work further identified 17 variants that directly increase the risk of developing type 2 diabetes, and then, via biological processes linked to type 2 diabetes, indirectly increase cancer risk.

Dr Robertson said: “In time, this could help doctors to identify people earlier who are at risk of both type 2 diabetes and certain cancers, while paving the way to better, more personalised ways to prevent and treat the conditions.

“It’s important to remember that people who have genes that are linked to type 2 diabetes and cancers can still take steps to reduce their risk of both conditions, by getting support to manage your weight, eating well, keeping active and not smoking.”

Dr Helen Croker, of the World Cancer Research Fund (WCRF), which helped fund the study, said: “WCRF is proud to fund this important research which looks at a population of people that is particularly vulnerable to cancer.

“As cancer is now the leading cause of death among people with diabetes, understanding the complex genetic interplay between type 2 diabetes and several cancer types is crucial for driving prevention strategies for this group of people.”