The Cancer–Diabetes Relationship: 9 Cancer Types Increase Diabetes Risk

Whether a cancer diagnosis affects diabetes risk—whether cancer causes diabetes—is a frequently asked question. Researchers at Sungkyunkwan University in Seoul, South Korea, therefore examined medical data from more than half a million men and women over 10 years, finding that nine cancer types increase the risk of subsequent diabetes .

Diabetes risk was highest in the first 2 years after cancer diagnosis. The study ran from 2003 to 2013.

Many earlier studies suggested the reverse relationship: diabetes was considered a risk factor for various cancers. Limited evidence, including this study, suggests increased new diabetes risk particularly after pancreatic, colorectal and breast cancer diagnoses.

These data suggest evidence that, apart from obesity, inactivity and smoking, independently of known diabetes risk factors , cancer is associated with increased diabetes risk.

Routine diabetes screening may therefore be important for cancer patients. Many experienced centers already monitor diabetes parameters during long-term follow-up.

Diabetes risk after pancreatic cancer found 5 times higher

The study included people aged 52-58, totaling 524.089 men and women without previous cancer. Over a median 7-year follow-up, 15.130 were diagnosed with cancer. Those diagnosed tended to be older, daily alcohol consumers, with higher body mass index and more comorbidities (additional diseases).

• The most important finding: Over 10 years, among 26.610 diabetes cases, 834 arose after cancer development. A cancer diagnosis increased diabetes risk 1.35-fold, independently of other risk factors such as age, sex, metabolic factors and comorbidities.
• Subgroup analysis found a 5.2-fold increase in diabetes risk with pancreatic cancer.
• Kidney, liver, gallbladder, lung, hematological (blood and marrow), breast, stomach and thyroid cancers also significantly increased new diabetes risk.
• Testicular and brain tumors were associated with a small increase. No increased risk was observed after uterine, ovarian, head and neck, esophageal or prostate cancers.

Because risk was highest during the first 2 years after diagnosis, treatments such as corticosteroids or chemotherapy may play a role. However, cancer’s direct effects may also increase diabetes risk; cancer cachexiais notably associated with insulin resistance, impaired glucose tolerance and diabetes.

Conclusion

Factors related to cancer itself and its treatments may increase diabetes risk. Closer monitoring can therefore be planned particularly for the 9 cancers listed: pancreatic, kidney, liver, gallbladder, lung, hematological, breast, stomach and thyroid. Further studies are needed to investigate specific causes and personal factors and establish optimal management strategies.