Diabetes could increase the risk of developing pancreatic cancer, new study finds

A study has shed fresh light on the link between type 2 diabetes, often caused by poor diet, and pancreatic cancer, a condition which kills 28 Britons every day.

Around 10,800 people are diagnosed with pancreatic cancer in the UK each year, making it the 10th most common cancer in the country.

In the latest study, published in JAMA Network Open, researchers in South Korea investigated whether diabetes increases the risk of developing pancreatic cysts – some of which can become pancreatic cancer. 

The pancreas is a pear-shaped gland, about the size of a hand, tucked deep behind the stomach, which produces insulin, a hormone needed to move sugar from the blood into cells, where it can be burned as energy. 

Pancreatic cysts are fluid-filled sacs in the pancreas, often found incidentally on scans and more common with age.  

They are usually benign, which means they are not a form of cancer, but sometimes there is a change in the cells that line the pancreatic duct, and the cyst can develop into a cancerous tumour.

Because of its location – and its relatively small size – doctors often can’t feel a pancreatic tumour during a routine physical exam, which is another reason the disease is so difficult to detect early.

The connection between type 2 diabetes and pancreatic cancer is well-established but complex, often described as a ‘chicken and egg’ scenario because both diseases affect the pancreas. 

Doctors first started exploring the possibility of a link between diabetes and pancreatic cancer in the 1940s and 1950s. 

Several reports had come out saying that patients with pancreatic cancer were more likely to also have diabetes than other people. This has been shown for type 2 diabetes as well as type 1 and young-onset diabetes.

Since then, many studies have shown a link between the two conditions. Overall, it seems that people with diabetes are around twice as likely to be diagnosed with pancreatic cancer than the general population.

Roughly one in ten pancreatic cancers are caused by being overweight or obese and obesity is the primary driver of type 2 diabetes, accounting for 80–85 per cent of the overall risk. 

The latest study, conducted by researchers from Seoul National University College of Medicine and other South Korean institutions, tracked 3.85million adults based on insurance claims data, 8.6 per cent of whom had diabetes, for ten years and compared people based on glucose status. 

People were grouped into the following categories: normal blood sugar, prediabetes, those who had diabetes for less than five years and those who had diabetes for more than five years. 

The researchers tracked who developed pancreatic cysts over time to find out how much higher the risk is in one group compared to another over time. 

The study found that the longer someone had diabetes, the higher their risk of developing pancreatic cysts.

At any time point, people with long-standing diabetes had 1.37 times the risk of developing a pancreatic cyst compared to those with normal glucose levels. 

Those who had lived with diabetes for more than five years had a 37 per cent higher risk compared with those who had prediabetes, who had a six per cent higher risk.

This risk was particularly elevated in individuals aged younger than 60 years with diabetes, males with diabetes and current smokers with diabetes. 

Previous research found that around one in five pancreatic cancers are caused by smoking.

Cigarettes, cigars, pipes and chewing tobacco all raise the risk.

However, the JAMA Network Open study found that only 0.8 per cent of the population developed cysts over 10 years.

Among those who developed cysts, 4.1 per cent later developed pancreatic cancer.  But in the total population, only 0.7 per cent developed pancreatic cancer overall. 

The study highlights that younger diabetic men might warrant more attention.

Previous studies have found that getting older is one of the biggest risk factors for pancreatic cancer.

Almost half of cases are diagnosed in over-75s – and it is rare in under-40s.

This is a common theme across many cancers. As Cancer Research UK explains: ‘Over time, the cells in our body become damaged. Cancer develops when damage in the same cell builds up.’

Despite this, pancreatic cancer incidence is rising more rapidly in younger age groups.

There is debate among researchers regarding whether this represents a true increase in cancer cases or increased detection. 

Some experts suggest this may reflect better detection of smaller, earlier-stage tumours.

Despite rising incidence, mortality rates among young patients have remained relatively stable, suggesting the increase in cases may be largely due to increased diagnostic screening rather than a spike in lethal disease.