Diabetes and chemotherapy

If you are diabetic, you need to eat regularly to keep your blood sugar stable. Most people with diabetes are used to juggling their need for food with their diabetes medicines. Chemotherapy can make you feel sick or be sick. You may not want to eat and so this can be a problem. If you can't eat, your blood sugar could drop too low, causing faintness, sweating and coma. This is called a hypoglycaemic attack.

There are different types of diabetes and depending on which type you have will alter how you manage it. If you have

• Type 1 you need to have regular insulin injections
• Type 2 you may be able to control it with either diet or with a combination of diet and tablets. More rarely people with type 2 need to have insulin injections

If you control your diabetes with diet or tablets it should be possible to manage it during chemotherapy without too many problems. You must discuss the options with your doctor first, but it may be suggested that you don’t take your diabetes tablets on chemotherapy days, for example.

If you are an insulin dependent diabetic, it can be more tricky. If you are unable to eat your normal diet, you will have to measure your blood sugar a bit more often than you usually would. But with many chemotherapy drugs these days sickness can be well controlled. There are very good anti sickness drugs available that can help even with chemotherapy drugs that traditionally have made people very sick. You may lose your appetite and have to force yourself to have something to eat regularly. Meals in a drink can help. They are rich in calories and you can sip them through the day. Your doctor can give you a prescription for these. There are many different brands, including Complan, Fresubin, and Build Up. Steroids are used with some chemotherapy combinations and these may upset your sugar balance. You may also be at slightly higher risk of infection during chemotherapy than people who are not diabetic.

You and your doctor will need to plan a bit more carefully than would be necessary if you weren’t diabetic. It may be a good idea for you and your cancer doctor to talk to your diabetes specialist. If you are dependent on insulin injections, your doctor may suggest that you have the first course of chemotherapy in hospital so that the nurses can keep an eye on you. Then, if you need sugar in a hurry, it can be given through a drip rather than by mouth. It is possible for you to have insulin and sugar solution (dextrose) given together through a drip in hospital. The insulin dose is based on hourly or 2 hourly blood sugar tests. But this is unlikely to be needed for most people.