A Danish study conducted by the University of Copenhagen has found that some common types of cancers increase the risk of developing type 2 diabetes (T2D), with elevated risks of mortality for patients that do develop T2D following a cancer diagnosis.
“Our study demonstrates that there is an elevated risk of developing diabetes if a person is affected by lung, pancreatic, breast, brain, urinary tract or uterine cancers,” said co-author of the study Associate Prof. Lykke Sylow.
As part of the study, researchers examined a Danish data set from 2000 to 2015 consisting of 112 million blood samples from 1.3 million Danes, of whom more than 50,000 developed cancer.
The researchers found that being diagnosed with any cancer at all on average will increase the risk of developing T2D by 9 percent.
Risks for developing T2D are the highest for patients with pancreatic, brain, and other nervous system-related cancers; with an increased risk of 40 to 50 percent for nervous system cancers and a 500 percent increased risk for those with pancreatic cancers.
Patients with lung, breast, and urinary tract cancers have a lower risk of developing T2D, with an overall risk of around 20 to 38 percent.
However, melanoma (skin cancer) and lymphatic and blood-type cancers such as leukemia, lymphoma, and myeloma are linked with reduced risks of T2D, with the cancers linked to a decreased risk of 20 percent.
The findings in the report are supported by a 2018 Korean study published in Jama that had similar findings associating cancer with T2D development.
While researchers could not find anything definitive about why certain types of cancers have a stronger association with developing diabetes, the authors speculate that it may be due to the secretion and signaling of cancer cells in the body.
“We know that cancer cells are able to secrete substances that can affect organs and possibly contribute to an increased incidence of diabetes,” said Sylow.
The reverse of the findings has also been observed, with more studies reporting diabetes as a risk factor for cancer.
Further, researchers also observed that the development of T2D in cancer patients also increased mortality risks by 21 percent, with increased life expectancies observed in cancer patients that do not develop the comorbidity.
“Across all cancer sites we observed, that cancer patients without diabetes survived longer compared to cancer patients diagnosed with diabetes,” said Prof. Christoffer Johansen.
The researchers suggest screening for diabetes in cancer patients for early intervention to improve the effects of treatment.
“Our results suggest that it might be relevant to consider diabetes screenings in relation to those cancers where we found an elevated risk of the disease,” said Sylow. “We have outstanding opportunities to treat diabetes and early intervention could have an impact on certain cancer patients.”
The study was published in American Diabetes Association (ADA) on May 27. ADA is an online, peer-reviewed open access journal on diabetes.