Diabetes Awareness Week: Tips for managing your diabetes during cancer treatment

5 minute read time.

an image of a blood glucose meter

Diabetes Week is held in the second week of June every year. In this blog, Content Developer Azmina gives tips for managing your blood sugar levels during cancer treatment.

Diabetes Week takes place from 10th to 16th June 2019. The charity Diabetes UK organises this special week to spread awareness of diabetes, encourage people to talk about the condition openly and raise money for research.

Managing both cancer and diabetes

About 1 in 5 people with cancer (20%) also have diabetes. Managing both conditions can be challenging, but your specialist diabetes team can give you extra support during your cancer treatment.

Some treatments for cancer can affect the amount of sugar in your blood. This means that doctors may have to plan your treatment more carefully. It is important that you are involved in this planning and that your needs are considered.

Monitoring your blood sugar

While you are being treated for cancer, you should aim to keep your blood sugar within a safe range. This will help protect your immune system, which needs to be strong to fight the cancer.

There are 2 different types of diabetes and some people with type 2 may not be used to testing their blood. However, everyone with diabetes who is having cancer treatment should monitor their blood sugar regularly. Your diabetes team will give you a blood-testing kit, explain what to do and tell you the sugar level you should aim to achieve.

If you already monitor your blood sugar, you may need to do so more often during your cancer treatment.

Sickness and changes in your appetite

Cancer or its treatments can sometimes make you feel sick or be sick. Chemotherapy, radiotherapy, hormonal therapy and targeted therapy can all cause sickness.

a quote from our supporter Lynn

Being sick can be a problem if you have diabetes because you may not want to eat. You may also temporarily lose your appetite during cancer treatment because you feel too tired to eat or foods taste different. Alternatively, some medicines such as steroids may make you want to eat much more than usual.

Here are some tips for coping with sickness and changes in your appetite:

1. If you are being sick or cannot follow your normal diet, contact your diabetes team. They will tell you if you need to adjust your dose of insulin or tablets.

2. Check your blood sugar more regularly (at least every 4 hours when you are sick, including at night). If it is very high and you use insulin, also test your blood or urine for ketones. These are chemicals that can sometimes build up in the body. Contact the hospital straight away if you have ketones.

3. If you do not eat enough food, your blood sugar may drop too low. This is known as hypoglycaemia or a ‘hypo’. Symptoms include trembling, sweating, having trouble concentrating and suddenly feeling dizzy, tired, uneasy or irritable.

To treat a hypo, have a fast-acting sugary drink or snack such as fruit juice, non-diet cola or lemonade, glucose tablets or a small handful of sweets. You may need to follow this up with another snack containing slower-acting carbohydrate, such as a couple of digestive biscuits, a slice of bread or a glass of milk.

4. To avoid hypos, try to eat the same amount of carbohydrates as normal and have small but regular snacks. You can choose foods that are easy to digest, such as soup, milk puddings or ice-cream, or dry foods, such as toast or plain biscuits.

5. Even if you cannot manage to eat, remember to keep drinking so that you stay hydrated. Aim to drink a cup of fluid every hour. If you have a poor appetite, your doctor can prescribe you meals in nourishing drinks to sip through the day.

6. Get urgent medical help if you continue to vomit or cannot keep down fluids.

7. If you have a bigger appetite during cancer treatment, try to follow a balanced, healthy diet. This will help you avoid putting on too much weight and control your blood sugar.

8. Your cancer specialist and diabetes team can give you more detailed advice about coping with side effects. For example, they may prescribe you drugs to treat sickness and explain how to improve your appetite or maintain a healthy weight.

Further information

For more information about managing your blood sugar and dealing with other side effects (including diarrhoea, the risk of infection and slow wound healing), have a look at the cancer and diabetes information on our website. Macmillan has also produced a booklet called Diabetes and cancer treatment in partnership with Diabetes UK. You can order a free copy at be.macmillan.org.uk or by calling 0808 808 0000.

an image of our Diabetes and cancer treatment booklet


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  • FormerMember
    <p>Hello,&nbsp;Wave</p> <p>I have recently been diagnosed with gall bladder/bile duct cancer, and also have Type 2 Diabetes (which I was controlling with Metformin). In October I went on a strict weight loss diet (in competition with my husband, who had to lose a stone and get his cholesterol down after his quadruple heart bypass last summer) and I have lost nearly 4 stone since then. I am now just under 15 stone (6ft tall) and am just below the middle of the Overweight level on BMI charts. At my heaviest I was actually 22.5 stone!.</p> <p>I feel like I have shrunk my stomach and can only eat small amounts of strangely, mainly dairy foods - full fat milk and cheese. I do have some fruit but am struggling with vegetables which cause bloating and abdominal discomfort.</p> <p>Despite this my blood sugars are continually high and my Diabetes Nurse is considering starting me on Insulin. I fear my tumour may be affecting my pancreas&#39;s ability to produce any insulin rather than my gall bladders ability to manufacture and release bile to digest fats. I have an oncology appointment on 19th June to discuss the results of my biopsy and the chemotherapy option he has chosen.He didn&#39;t have all the results when I saw him 2 weeks ago.&nbsp;</p> <p>Until recently I haven&#39;t had any symptoms from my &#39;Alien&#39; Alien which has been identified through blood tests, an ultrasound, CT scan, MRI and Liver Biopsy. I now have pain in my right shoulder and left shoulder blade which my Macmillan Nurse believes may be due to stretching of the liver capsule.</p> <p>Oddly I have not been concerned about the cancer at all and have been really calm and sleeping well - I put this down to taking a GOOD QUALITY CBD oil with 0.16% THC in, and drinking CBD tea at night.I am more concerned that my blood sugars are so high when I am having so few Carbs. I am also worried that my Oncologist wants me to stop taking CBD oil when I commence chemo, even though I have researched this product, and there are testimonials from people who&nbsp;believe it&nbsp;has helped shrink their cancer when used alongside chemo and may help alleviate some of the side-effects (although obviously the producers themselves cannot make any medicinal claims and it has to be sold as a food supplement.</p> <p><span style="text-decoration:underline;"><strong>Is there anyone else out there who is battling to control their blood sugar whilst seemingly eating &#39;fresh air;&#39; and on chemo? Any tips appreciated - there are so few foods I can tolerate and even then only small amounts 3 times a day.</strong></span></p> <p>Oh, and I forgot to mention, I have Multiple Sclerosis and take a wheelbarrow load of medications to control that too.</p> <p>I am also a Nurse and dread being patronised by other healthcare professionals - not a criticism but I do have a good brain and anatomical knowledge although I was a CHD Practice Nurse rather than a cancer specialist.&nbsp;</p> <p>Thank you, Stay well.</p> <p>Big Jen xx</p> <p>PS. Its my 59th birthday tomorrow 15th June, and I fully expect to be here to celebrate the BIG ONE next year.</p>
  • <p>Hi </p> <p>I hope you don&#39;t mind me responding here - my name&#39;s Ellen and I work on the Community team here at Macmillan. Thank you for sharing your experience with us on our blog and I&#39;m sorry nobody has been back to you just yet.&nbsp;</p> <p>I can see from your post that you&#39;re looking to talk to others who may be going through something similar. I wonder if you&#39;ve thought about posting your question in our Chemotherapy forum as there may be someone there who&#39;s going through something similar. I can see you&#39;re also a member of the Liver cancer forum and the Bile duct cancer forum - you might find it useful to post there too.&nbsp;</p> <p>To get started, head over to the group you&#39;d like to post in and select &#39;start a discussion&#39;.</p> <p>I hope some of this helps.</p> <p>Best wishes,</p> <p><strong>Ellen</strong><br /><strong>Macmillan Community Team</strong>&nbsp;</p>