Blood Cancer and Diabetes Link Explained

Patients with multiple myeloma and diabetes have poorer survival rates than those without diabetes. This may be due to higher insulin levels accelerating tumor growth, says new study.

About 13% of the American population has diabetes, and its prevalence is increasing at an alarming rate. Multiple myeloma, a blood cancer of plasma cells in the bone marrow, is the second most common blood cancer in the United States, disproportionately affecting non-Hispanic Black adults. Among them, it is the most common form of blood cancer.

The new study used data from electronic health care records of 5,383 patients with multiple myeloma. Of those, 15% also had a diabetes diagnosis: 12% of white and 25% of Black patients.

This and prior studies showed that patients with multiple myeloma and diabetes have lower survival rates. However, after analyzing results by race, the researchers found decreased survival only among white patients with blood cancer and diabetes but not Black patients with the condition.

"What we did not expect to see here was that diabetes was actually associated with worse survival outcomes among white individuals with myeloma, but not Black individuals," said Shah, M.D., a multiple myeloma specialist at Memorial Sloan Kettering Cancer Center.

The study shows that overall survival rates decreased with age. In the study's cohort, diabetes was 50% more prevalent among Black patients aged 45 to 60 years old than white patients over 60. As younger patients may tolerate multiple myeloma treatments better than older individuals, this could explain some of the racial differences in survival outcomes.

When investigating the mechanisms behind these findings, the researchers found that multiple myeloma tumors grew more rapidly in non-obese diabetic mice than in non-diabetic controls.

Because an insulin-related signal was over activated in the diabetic mice, the researchers believe higher insulin levels associated with diabetes may accelerate cancer growth.

The limitations of the study include its retrospective nature. Moreover, it did not examine how the quality of care patients with diabetes receive may impact survival outcomes.

While drugs are important, as oncologists, we need to also look at comorbidities and modifiable risk factors to improve patient survival outcomes. Therapies and lifestyle changes can go hand in hand.

- Shah

Cancer and diabetes link

Diabetes, primarily type 2, is associated with a higher risk for some cancers, including liver, pancreas, endometrium, colon and rectum, breast, and bladder.

The link may be partly explained by shared risk factors between the two conditions, such as aging, obesity, diet, and physical inactivity.

Men are more likely to develop diabetes and cancer than women. Race may also play a role, as Black people have a higher cancer and diabetes burden.

Studies suggest that possible mechanisms for a direct cancer and diabetes link could be hyperinsulinemia (elevated insulin levels in the blood), hyperglycemia (increased blood sugar), and inflammation.

According to the American Diabetes Association, adopting some healthy lifestyle choices may reduce the risk of diabetes and cancer:

• Choose a healthy diet rich in fresh vegetables and fruits, whole grains, lean meat, and low-fat or non-fat dairy products. Limit sodium and sugar intake.
• Stay active by exercising five days a week, such as taking a 30-minute brisk walk.
• Quit smoking and reduce alcohol.
• If you are overweight, work towards shedding even 7% of your body weight.

While blood cancer and diabetes link needs to be further explored, healthy lifestyle choices can reduce the risk of both conditions.