Type 2 Diabetes and Cancer
Researchers are still working to understand exactly how type 2 diabetes and cancer are connected. Studies have found that people with type 2 diabetes may have a higher risk of developing certain types of cancer.
What is type 2 diabetes?
Type 2 diabetes (T2DM) is a condition that causes high blood sugar (glucose) levels. Insulin is a hormone made by the pancreas that is needed to control blood sugar levels. Type 2 diabetes develops when the body has trouble using insulin properly (called insulin resistance), doesn’t make enough insulin, or both. This is different from type 1 diabetes, an autoimmune condition in which the immune system destroys the insulin-making cells in the pancreas, so the body makes little or no insulin.
Many body functions depend on insulin because it helps cells absorb and use glucose for energy. Over time, having high blood sugar levels can cause changes that affect overall health. This may increase the risk of certain cancers, including colorectal, liver, gallbladder, breast, pancreatic, and endometrial cancers.
Risk factors for type 2 diabetes include:
- Excess weight
- Lack of physical activity
- Smoking
- Older age
- A family history of diabetes
Many of these same factors are also associated with a higher risk of certain cancers.
What cancers are more common in people with type 2 diabetes?
People with type 2 diabetes can have a higher risk of:
- Colorectal cancer
- Liver cancer (also called hepatocellular cancer)
- Gallbladder cancer
- Breast cancer
- Pancreatic cancer
- Endometrial cancer (cancer of the lining of the uterus)
If you have type 2 diabetes and have been diagnosed with cancer, talk to your diabetes doctor (endocrinologist) and cancer care team so they can work together to support your care and treatment.
What is the connection between type 2 diabetes and cancer?
More research is needed to better understand the relationship between type 2 diabetes and cancer. Several factors may help explain how the two are related, but researchers believe the connection is complex. Studies suggest the connection comes from the conditions sharing similar risk factors and from some of the changes that can happen in the bodies of people with type 2 diabetes.
Shared risk factors
One way cancer and type 2 diabetes are related is that they share some of the same risk factors. These include:
- Having excess body weight (overweight or obesity)
- Not getting enough physical activity
- Eating an unhealthy diet
- Smoking
Changes caused by type 2 diabetes
Certain biological changes that happen in people with type 2 diabetes may also help explain the higher cancer risk:
- Too much insulin in the blood: People with type 2 diabetes often have high levels of insulin in their blood, especially early in the disease. Insulin can act like a growth signal and may help cancer cells grow and spread.
- High levels of a growth protein called IGF-1: High insulin levels cause the body to make more of a protein called IGF-1 (insulin-like growth factor-1). This protein tells cells to grow and may stop damaged cells from dying the way they should, which could allow cancer cells to develop.
- Chronic inflammation: Type 2 diabetes is linked to ongoing, low-level inflammation in the body. Over time, this kind of inflammation can damage DNA and make it easier for cancer to develop.
- High blood sugar: Cancer cells use a lot of sugar for energy. Having high blood sugar over a long period of time may help fuel the growth of cancer cells, though researchers are still studying how much of a direct role blood sugar plays on its own.
Take steps to protect your health
Having type 2 diabetes does not mean you will get cancer. Many people with type 2 diabetes never develop cancer. Talk with your healthcare team if you have questions about type 2 diabetes, cancer risk, or ways to stay healthy.
If you have type 2 diabetes, here are things you can do to help lower your cancer risk:
- Keep your blood sugar under control by following your diabetes treatment plan.
- Get to and stay at a healthy weight.
- Be physically active.
- Eat a healthy diet.
- Avoid tobacco products.
- Limit or avoid alcohol.
- Get recommended cancer screening tests.
Know Your Cancer Risk
Take the ACS CancerRisk360™ assessment to learn more about what you can change to improve your health. By taking 5 minutes to answer a few questions, we will give you a personalized roadmap of actions with helpful resources you can use to lower your risk of cancer.
- Written by
- References
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
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Last Revised: July 10, 2026
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