For many years, people with type 2 diabetes were most likely to die from heart disease or kidney problems. In the past, patients with type 2 diabetes had a very high risk of cardiovascular disease and chronic kidney disease. However, with the use of statins (to lower cholesterol) and ACE inhibitors/angiotensin receptor blockers (to control blood pressure), the risk of cardiovascular death in diabetes patients is now only slightly higher than in people without diabetes.

Today, the number one cause of death in people with type 2 diabetes is cancer.

Which cancers are more common?

People with diabetes have a higher risk of certain cancers, especially:

• Liver cancer
• Pancreatic cancer
• Uterine (endometrium) cancer
• Colorectal cancer (colon/rectum)
• Breast cancer
• Gallbladder cancer

How much higher is the risk?

• Overall, the chance of getting cancer is about 10% higher than in people without diabetes.
• The chance of dying from cancer is about 15–20% higher.
• For some cancers (like liver and pancreas), the risk can be 2–3 times higher.

Why is this important?

• Because cancer is now the main cause of death in diabetes, regular cancer screening (check-ups) is very important.
• Lifestyle choices play a big role: not smoking, being physically active, eating healthy, and keeping blood sugar under control can reduce the extra risk almost completely.

What about medicines?

• Metformin, the most common diabetes medicine, may also lower the risk of some cancers.
• That’s why doctors often start treatment with metformin (unless it is not safe for you).

If you have type 2 diabetes, your biggest health risk is now cancer, not heart disease.
The good news: With healthy lifestyle choices, regular cancer screening, and proper treatment, you can greatly reduce this risk.

Guidelines mainly focus on reducing cardiovascular risk and the risk of kidney failure, often using very expensive drug therapies. In contrast, regarding the main cause of death—cancer—guidelines only recommend that patients with type 2 diabetes should undergo regular cancer screenings.

In earlier guidelines, lifestyle changes were recommended at diagnosis, but metformin treatment was also started immediately unless contraindications existed. Metformin has been shown to reduce the risk of several types of cancer. We therefore recommend initial treatment with metformin in all patients with type 2 diabetes, unless contraindicated.

Research Overview: Cancer Mortality in Type 2 Diabetes

1. Increased risk of cancer and cancer-related death

• A large Swedish cohort study (1998–2012) showed:
  • 10% higher incidence of all cancers in T2D compared to controls (HR 1.10).
  • 23% higher mortality after a cancer diagnosis (HR 1.23).
  • Overall, cancer-related mortality was ~14% higher in T2D patients (HR 1.14).
  • Risks were especially high for liver, pancreatic, and uterine cancers (up to 3-fold).

2. Survival after cancer diagnosis

• A newer Swedish registry study (2024):
  • T2D patients with cancer had a 3.75-fold higher overall mortality compared with people without cancer.
  • Key risk factors: smoking (RR ~2.15) and low physical activity (RR ~1.59).
  • HbA1c, lipids, etc. had only a modest influence.

3. Changes in outcomes and life expectancy

• A British study (2024):
  • T2D roughly doubles premature mortality compared with the general population.
  • However, patients achieving multiple risk factor targets (non-smoking, optimal HbA1c, blood pressure, cholesterol) had no significant increase in overall or cancer-specific mortality.

4. Other evidence and meta-analyses

• A review of six large cohorts (PLoS Medicine): higher glucose levels increased cancer mortality (≈20% in men, ≈30% in women).
• A UK study (Diabetologia, 2023):
  • 18% higher overall cancer mortality in T2D.
  • Nearly doubled risk for liver, pancreatic, and uterine cancers.

Numbers at a Glance

Interpretation of the Evidence

• Data are robust and consistent: Type 2 diabetes is associated with a slightly higher cancer risk and a clearly higher cancer mortality.
• Strongest links: liver, pancreas, uterus; also colorectal cancer depending on sex.
• Lifestyle factors (smoking, activity) are decisive.
• Early, comprehensive treatment can close much of the mortality gap.

Conclusion

• Cancer mortality in type 2 diabetes is on average 10–20% higher, depending on the study.
• For certain cancers (liver, pancreas), the risk is much higher.
• Modifying risk factors (non-smoking, physical activity, good glucose control, healthy weight) can almost completely eliminate the extra risk.

Shift in Leading Cause of Death: Cancer vs. Cardiovascular

In many large cohorts, over the past two decades the leading cause of death in T2D has shifted from cardiovascular disease to cancer.

• England (2001–2018): Cancer deaths rose from 22% → 28%, cardiovascular deaths fell from 44% → 24%. By 2018, cancer had overtaken cardiovascular disease.
• Denmark (2002–2019): Cancer became the leading cause of death in T2D; cardiovascular mortality decreased sharply.
• Scotland (2009–2014): Leading cause cancer (27.8%), followed by heart disease (24.1%).
• Japan (2023): Malignancies accounted for 46.9% of all deaths; cardiovascular + cerebrovascular together only 11.7%.
• South Korea (2002–2013): Cancer (24.8%) slightly ahead of cardiovascular disease (22.0%).

Overall: Across countries, cancer is now at least equal to or more common than cardiovascular disease as a cause of death in type 2 diabetes. This shift is driven by better cardiovascular prevention but slower progress in cancer mortality reduction.

 For people with type 2 diabetes, we need both: continued strong cardiovascular prevention and more focus on cancer prevention and early detection (especially liver, pancreatic, and colorectal cancers).

Obesity further increases the risk – and in T2D, obesity-associated cancers (liver, pancreas, kidney, etc.) are particularly striking. However, the shift in the leading cause of death toward cancer is observed across entire T2D populations and persists in analyses after adjustment for BMI.

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