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I Have Cancer and High Blood Sugar. What Do I Do?

It is not uncommon for someone with cancer to have elevated blood sugar (glucose) levels. Your doctor may have even told you that you have diabetes. Diabetes is high blood sugar. Diabetes is an energy problem, when your body cannot fully process the energy in the food you eat. The result can be high blood sugar. Your doctor may also call these glucose levels, but glucose and blood sugar mean the same thing. Insulin is a hormone made by the pancreas that helps your body use and store glucose. High blood sugar levels can occur when your pancreas does not produce enough insulin or your body isn’t able to use the insulin properly. When this happens, your body is not able to use the sugar from food. Instead, the sugar stays in your blood making high blood sugar levels.

Why are my blood sugars high? There are a few reasons why your blood sugars may be high. These include:

  • Steroid induced diabetes
  • Type of cancer (such as pancreatic cancer)
  • Stress from being diagnosed with cancer

Steroid Induced Diabetes:

What are steroids?

Steroids are medications that are most often used as an anti-inflammatory. They may be used for a short period of time or long term.

Why might I be taking steroids?

  • To help with an autoimmune disease
  • Post-transplant immunosuppression
  • Reduce swelling, possibly due to cancer in brain
  • To combat side effects of some cancer treatments

What are some side effects I may have from taking steroids?

  • Increased appetite or thirst
  • Mood changes
  • Trouble sleeping

Any of these symptoms may contribute to high blood sugar levels. Even if a person did not have diabetes before taking steroids, they still may have high blood sugar levels while taking them and a short period of time after taking them.

Will blood sugar levels return to normal once off of steroids?

Most likely blood sugar levels will return to normal after a few days of stopping the steroid. It is very important to take all medications including steroids as directed by your healthcare team. Do not stop taking medications, including steroids, without first talking with your healthcare team.

For some people, it may take a while for sugars to return to normal. This depends on other factors such as length of time of steroid use, weight before and after steroid use, and dose of steroid.

For some people, their blood sugar levels may not return to normal. This may happen because of pre-existing risk factors for diabetes before taking steroids such as family history, weight, previous high blood sugar levels.

Pancreatic Cancer and Diabetes:

The pancreas is the organ in the body that releases insulin. When cancer develops in the pancreas, it damages the tissue. You pancreas may not be release insulin properly, or your pancreas may not release enough insulin. This may lead to diabetes because your body’s cells may not be able to use the blood sugar molecules properly.

Will my pancreas function normally after treatment?

  • The pancreas cannot replace damaged cells with healthy ones.
  • Medications may provide the body with the needed hormones (insulin and glucagon) that the pancreas releases. Digestive enzymes can also be taken as a medication if the pancreas can no longer produce them.

Stress and Diabetes:

Stress results when something causes your body to behave as if it were under attack. Stress can affect blood sugar levels.

Stressors may include:

  • Your diagnosis, tests, finances, or family.

Why does stress affect blood sugar levels?

  • ‰ÛÜStress hormones can affect blood sugar levels directly.
  • Stress may cause you to not take good care of yourself. You may forget to take medications or check blood sugars. You may not be exercising or eating properly. You may not be sleeping well.

The stress of understanding, coping, and treating cancer is a lot to manage. It is not uncommon for someone who does not have diabetes to have high blood sugar levels at some point in the cancer journey. This may be from the body’s response to the cancer itself, the treatment, or just to the stress living with cancer.

What are some healthy ways of coping with stress?

Exercise, practice deep breathing, meditate, take a bath, listen to calming music, or do any other safe activity you find relaxing.

Managing High Blood Sugar Levels:

What can I do to control my blood sugar levels?

  • Take medication as prescribed. Be sure to talk with your healthcare providers and/or your pharmacist if you have any questions about your medication.
  • Monitor your intake of carbohydrates. Carbohydrates are foods that break down to sugar in the body. Examples include bread, pasta, rice, fruit, milk, yogurt, potatoes and corn. Eat about the same amount of carbohydrate daily. Adult women may need 45 to 60 grams of carbohydrate per meal, and adult men may aim for 60 to 75 carbohydrate grams per meal
  • Serving sizes of 1 carbohydrate serving (15 grams of carbohydrate) are as follows:


1 slice


1/3 cup cooked


½ cup cooked


8 ounces (1 cup)


1 small piece or ½ cup diced/canned

  • Speak with a Registered Dietitian or a Certified Diabetes Educator about your specific carbohydrate intake recommendations.
  • Stay as active as possible. Exercise is very helpful when it comes to controlling blood sugar levels. Even a 10 minute walk every day can help.
  • Check your blood sugar levels regularly throughout the day.

How do I check my blood sugar?

  • If you do not have a blood glucose meter, ask your doctor, pharmacist, or registered dietitian for information on how to get one.
  • Follow your doctor’s recommendations for checking blood sugars. For example, if the doctor says to get a fasting blood sugar every day, check your sugar before you eat breakfast in the morning. If the doctor says to check your blood sugar twice a day, then make sure you follow that suggestion.
  • The most important times to check your blood sugar are first thing in the morning, after meals, and right before bed. If you are having problems controlling your blood sugars, consider checking your blood sugars more often throughout the day.
  • Your healthcare team can tell you how often and when you should check your blood sugars during the day.
  • When checking blood sugars, it is a good idea to keep a log. In the log record the time, blood sugar, and medications taken to help determine trends.