Lake forest health and fitness: Diabetes could be a warning sign of pancreatic cancer

Tuesday 31 January 2017

Diabetes could be a warning sign of pancreatic cancer

"Experts have revealed the onset of diabetes, or existing diabetes getting much worse could be a sign of hidden pancreatic cancer," reports The Daily Express.

The media reports follow a press release of a study presented at the European Cancer Congress (ECCO) yesterday. The research analysed nearly a million people with type 2 diabetes in Belgium and Italy, some of whom went on to be diagnosed with pancreatic cancer.

The recent onset of diabetes appeared to be a possible warning sign of pancreatic cancer, with 25% of cases in Belgium and 18% in Italy being diagnosed within three months of a diabetes diagnosis. Faster progression of diabetes (where patients needed insulin or other more intensive treatments sooner) was also associated with a greater chance of being diagnosed with pancreatic cancer.

Pancreatic cancer is rare and often has a poor outcome, partly because it is difficult to detect at an early stage.

However, it's important to put these findings in context. Diabetes has previously been linked with pancreatic cancer, though it is unclear why. It could be that diabetes increases the risk of pancreatic cancer. What is probably more likely is that rapid onset or progression of diabetes could be a symptom of the cancer itself.

Diabetes is fairly common in the UK, with around 4 million cases, while pancreatic cancer remains very rare. Just because you have diabetes does not mean you will go on to get pancreatic cancer.

However, if you are concerned that you may have diabetes or that your diabetes is poorly controlled, you should talk to your GP.

There are also steps you can take to reduce your risk of developing diabetes.

Where did the story come from?

The study was carried out by researchers from the International Prevention Research Institute in Lyon, France. The study has not yet been published in a journal but was presented at the European Cancer Congress held in Amsterdam. The findings come from the press release.

Funding was provided by Sanofi, a French pharmaceutical company. The authors declare the sponsor had no influence on the study design, conduct, analysis and reporting.

This has been reported widely in the UK media, though not always accurately. The Mail Online claims the researchers "analysed nearly a million type 2 diabetics in Italy and Belgium who had been told they had pancreatic cancer" however this was the number of people in the database with diabetes. Only 2,757 people had been diagnosed with pancreatic cancer.

Moreover, The Daily Telegraph reports "50 per cent of patients diagnosed with pancreatic cancer had been diagnosed with type 2 diabetes the previous year". This is rather misleading and suggests 50% of all people with pancreatic cancer also have diabetes.

But this study only looked at people with diabetes. Of those who developed pancreatic cancer, half had received their diabetes diagnosis in the past year. The overall proportion of all people with pancreatic cancer who also have diabetes in the population is unknown.

What kind of research was this?

This was a retrospective cohort study looking at the association between type 2 diabetes and the diagnosis of pancreatic cancer.

The study is currently only available as a published abstract and was presented at the European Cancer Congress with an accompanying press release. A full study publication is not available so we can't fully critique the methods and analysis.

Pancreatic cancer has a notoriously poor prognosis as it is often hard to diagnose at an early stage due to a lack of symptoms or non-specific symptoms. Individual outcomes vary, but generally only 1% of all people diagnosed with pancreatic cancer live for more than 10 years after their diagnosis.

Diabetes has already been linked as a possible risk factor for pancreatic cancer, but in what context is uncertain. However, onset of diabetes or rapid deterioration of current diabetes could be a possible marker for early pancreatic cancer so could potentially aid earlier diagnosis.

What did the research involve?

The researchers used a prescription database (the Inter Mutualist Agency AIM-IMA) to identify 368,377 people receiving treatment for type 2 diabetes patients in Belgium between 2008 and 2013. They also identified 456,311 being treated in Lombardy, Italy, between 2008 and 2012.

These data were linked to pancreatic cancer data from the Belgium Cancer Registry and hospital discharge databases in Lombardy.

The rates of pancreatic cancer were analysed in association with time of first prescription of diabetes drugs, and use of different diabetes treatments.

What were the basic results?

In Belgium, 885 of 368,377 people with diabetes had pancreatic cancer. In Lombardy, 1,872 of 456,311 people with diabetes had pancreatic cancer.

Among all those with pancreatic cancer in the two regions, 50% had been diagnosed within one year of being diagnosed with type 2 diabetes.

In Belgium, 25% of pancreatic cancer cases were diagnosed within 90 days and in Lombardy 18% were diagnosed within 90 days.

When considering treatment, the researchers generally found that switching to more intensive diabetes treatments was also linked with a greater risk of pancreatic cancer diagnosis:

People who switched from oral diabetes drugs to more intensive treatment of incretin-based therapy (injected drugs that help the body produce more insulin) had 3.3 times the risk (95% confidence interval [CI] 2.0 to 5.5) of cancer diagnosis in the following three months.
This decreased to around a two-fold risk for 3 to 6 months after the first prescription of incretin drugs (hazard ratio [HR] 2.3, 95% CI 1.2 to 4.7) and again for 6 to 12 months after the first prescription (HR 2.1, 95% CI 1.2 to 3.9).
Switch from oral diabetes drugs or incretin to insulin injections was also linked with increased risk of pancreatic cancer (HR 11.9, 95% CI 10.4 to 13.6).
When comparing those who developed pancreatic cancer with those who remained cancer-free, switching from oral diabetes drugs to incretin or insulin injections happened sooner after diabetes diagnosis in those who developed cancer: median 372 days to switch to incretins and 315 days to switch to insulin in those who developed cancer versus median 594 days to switch to incretins and 437 days to switch to insulin.

How did the researchers interpret the results?

The lead researcher commented: "There is currently no good, non-invasive method for detecting pancreatic cancer that is not yet showing any visible signs or symptoms. We hope that our results will encourage the search for blood markers indicating the presence of pancreatic cancer, which could guide decisions to perform a confirmation examination like endoscopy."

Conclusion

This study uses a large prescription database to investigate the link between diabetes and pancreatic cancer, looking at the timing of first diabetes prescription and change in drugs prescribed.

Among people with type 2 diabetes, diagnosis of pancreatic cancer was linked with recent onset of diabetes or rapidly deteriorating diabetes. This suggests these could both be potential warning signs of hidden pancreatic cancer and indicate the need for more investigations.

While diabetes has previously been linked with pancreatic cancer, the nature of the cause and effect relationship remains unclear. It could be that diabetes increases risk of the cancer, or it could be that recent onset or deterioration of diabetes is a symptom of the cancer.

It had also previously been thought that incretin therapies could promote pancreatic cancer. However, it could be that incretin therapies and insulin therapies are often prescribed sooner in patients who have undiagnosed pancreatic cancer.

As the authors make clear, it is probably pancreatic cancer that causes deterioration of diabetes.

A limitation of this study is that it was carried out in two specific areas in Europe. Sociodemographic variations in diabetes or cancer prevalence, medical care or risk factors may mean the results are not fully applicable to the UK.

The findings are also based on a prescription database, so only look at raw data on numbers. The researchers haven't delved further into the nature of the individual diabetes and cancer diagnoses, investigations and treatment.

These are early findings presented at a conference. A full, published study is not available so it is not possible to analyse the methods and possible implications further.

It's not possible to say whether the findings could lead to more in-depth investigation of people with newly diagnosed or rapidly progressing diabetes, or whether this could make earlier pancreatic cancer diagnosis and improved survival rates possible.