How immunotherapy can affect your diabetes

Immunotherapies are cancer treatments that aim to stimulate the immune system to kill cancer cells. The stimulating effect can cause high blood sugar levels for people who have diabetes.

Rarely, immunotherapies can trigger diabetes in people who do not already have diabetes. If this happens, you will need to keep having diabetes treatment to control and monitor your blood sugar level.

Immunotherapy drugs that affect your blood sugar include:

The side effects of some immunotherapy drugs can be worse if you have diabetes. Your cancer doctor or specialist nurse can give you more information.

Controlling your blood sugar when having immunotherapy

A course of immunotherapy treatment may last a few months, but can also last a few years. Before treatment starts you may have a blood test to check your blood sugar level. The blood test will be done again during treatment. You may have more blood tests after treatment has ended. During treatment you will need to check your blood sugar level more often.

You may need to change your diabetes treatment. For example, you may have to:

  • start using insulin as well as taking tablets
  • change the dose of insulin you take
  • start taking tablets if your diabetes is diet-controlled.

It is important to tell your doctors how well you are controlling your blood sugar level during your treatment.

Talk to your doctor if you do not have diabetes, but develop any of its symptoms while having targeted therapy or immunotherapy. You can find out more about symptoms of diabetes at Diabetes UK.