On this page: Fatigue | Loss of appetite | Changes in taste or smell | Chewing and swallowing problems | Dry mouth | Nausea and vomiting | Constipation and diarrhoea | Other types of bowel irritation | Heartburn (Indigestion)
Cancer treatments kill cancer cells, but in the process they damage normal healthy cells and cause side effects. These side effects vary from person to person, and depend on the type of treatment, the part of the body treated, and the length and dose of treatment. Most side effects are temporary and go away after treatment ends. There are ways to control and manage side effects.
Some treatment side effects can, in turn, affect what you can eat and how much. These include:
Feeling anxious about the diagnosis and treatment can also affect your appetite. Talk to a family member or friend, the social worker at the hospital, or your doctor if you are experiencing these feelings.
|What it is||Side effects*
|surgery||the partial or total removal of a tumour or body part||difficulty swallowing (oesophagus, voice box), diarrhoea (bowel, stomach, pancreatic), incomplete absorption of nutrients|
|chemotherapy||the use of drugs to kill or slow the growth of cancer cells||loss of appetite, nausea, vomiting, constipation, diarrhoea, mouth sores, taste changes, difficulty swallowing, lowered immunity, fatigue|
*depends on area receiving treatment
|the use of radiation to kill cancer cells or injure them so they can’t grow and multiply||loss of appetite, fatigue, taste changes, nausea, vomiting, diarrhoea, dry mouth, difficulty swallowing, bowel obstruction, mouth sores|
|steroid therapy||drugs given orally or by injection||increased appetite, weight gain, increased risk of infection, stomach irritation|
|stem cell transplant||the process of replacing stem cells destroyed by high- dose chemotherapy||lowered immunity, sore mouth and throat, nausea, vomiting, diarrhoea, fatigue, loss of appetite|
|hormone therapy||drugs that block the hormones that help some cancers grow||weight gain, increased cholesterol levels|
|targeted therapies||drugs that attack cancer cells while minimising harm to healthy cells||diarrhoea, nausea, vomiting, constipation, taste changes, mouth sores, fever, increased risk of infection|
A common side effect of treatment is feeling extreme and constant tiredness (fatigue) that doesn’t improve with rest. Fatigue can be caused by treatment side effects that reduce the number of red blood cells (anaemia) or that affect your appetite.
"I was not as active before cancer as I am now. I walk a week. It gives me more energy and helps clear my mind. If I don’t do any walking, I really notice the difference in my energy levels and mood." – Rima
You may lose your appetite because of the effects of cancer itself, the treatment, or other side effects, such as feeling sick, not enjoying the smell of food, or feeling upset. This is a common issue for people diagnosed with cancer.
Some treatments and their side effects can change the way some foods taste or smell. Chemotherapy can change the taste receptors in the mouth. Radiotherapy or surgery to the head, neck and mouth area may damage the salivary glands and tastebuds on the tongue. Food may taste bitter or metallic, or may not have as much flavour as before.
People often say that, “All food tastes the same”, “Food tastes like cardboard”, “Food tastes metallic”, “I no longer like the taste of my favourite food” or “I’ve gone off red meat, chocolate and alcohol”.
It’s common to have taste changes during treatment and for a short time afterward. Sometimes it can take several months for taste changes to return to normal.
If you have a sore mouth, sore throat or swallowing difficulties, talk to your doctor, speech pathologist, dentist or dietitian – some of the suggestions for managing taste changes (see table below) will not be suitable.
See Understanding Taste and Smell Changes for more information.
"During treatment, I developed an active sense of smell. I hated certain smells and did all I could to avoid them. My mouth felt very dry, which made food taste unappetising. Adding extra sauce helped." – Helen
After surgery to the mouth or throat, chewing and swallowing may be difficult and painful. Radiotherapy and chemotherapy to this area can also cause temporary problems. If teeth are extracted, chewing may be more difficult. People with dentures who have lost weight may also find their teeth become loose, which can make eating difficult.
Signs that the texture of food is causing problems include taking longer to chew and swallow, coughing or choking while eating or drinking, or food sticking in your mouth or throat like a ball.
If you’re having difficulty swallowing, you may need to change the consistency of your food by chopping, mincing or pureeing (see types of food textures, below). This can make it easier to get enough nutrition, and reduce the risk of losing weight and strength.
A speech pathologist can monitor your ability to swallow during and after treatment, and suggest modifications to the texture of your food once your ability to swallow and chew begins to improve. Ask your doctor for a referral.
Sometimes, people may need to remain on a texture-modified diet after their treatment. However, this is different for everyone and will depend on the type of cancer or treatment received. In rare cases, a person with severe difficulty swallowing will need a feeding tube to ensure adequate nutrition. If this is required, your dietitian, speech pathologist or doctor will discuss it with you.
Food can be chewed but not necessarily bitten. It should be easily broken up with a fork and need little cutting. Sauce or gravy can be added to make it softer.
Food should be soft and moist and easily form into a ball in the mouth. Small lumps can be broken up with the tongue rather than by biting or chewing. Food should be easily mashed with a fork and may be presented as a thick puree with obvious lumps in it. Lumps should be soft and rounded with no hard or sharp bits.
Food is smooth, moist and lump-free. It may have a grainy quality and is similar in consistency to commercial pudding. The texture of smooth pureed food means it can be moulded, layered or piped to make it look more appealing.
If you have been told that you need to follow a texture-modified diet, you may find it difficult to know what to eat or drink. The sample menu below provides some meal, snack and drink suggestions for each of the different texture categories. You can also try some of the recipes.
Your dietitian can help to identify foods and fluids that will be easy to eat and drink, and can work out if the texture-modified diet is meeting your nutrition needs. A speech pathologist can also assess whether you need to change the consistency and thickness of fluids. Find a dietitian or speech pathologist.
||Minced and moist
|Breakfast||scrambled or poached eggs||porridge or wheat biscuits with lots of milk and little texture||strained or pureed porridge|
|Lunch||egg and mayonnaise sandwich with crusts cut off||soup with vegetable or meat pieces no bigger than 5 mm||well-cooked pasta that has been pureed in a blender with added sauce|
|Dinner||casserole with small pieces of tender meat and well-cooked vegetables||moist macaroni cheese||pureed chicken blended with extra gravy or sauce|
|Snacks||mango||mashed banana||pureed pear pushed through a sieve|
|Dessert||soft cake with lots of custard||soft cheesecake without the crust||ice-cream|
|Avoid||nuts, dried fruit, dry or gristly meat, raw vegetables, muesli, hard cheeses||nuts, hard vegetables, all bread and crackers, dried food, lollies (jubes, marshmallows)||meat, eggs, cereals or vegetables that have not been pureed in a blender, peanut butter|
* Some food may need modification for people requiring thickened fluid.
Radiotherapy to the head or neck area, some chemotherapy drugs and some pain medicines can make your mouth dry, cause mouth ulcers, or change the amount of saliva in your mouth. A dry mouth can increase the risk of tooth decay and infections such as oral thrush, which will make eating harder.
Feeling sick (nausea) and vomiting are often side effects of cancer, its treatment or some medicines. They often occur together, but not always. Vomiting sometimes follows nausea and may be caused by treatment, stress, food odours, gas in the stomach or bowel, motion sickness or even the thought of having treatment.
Some people experience nausea and vomiting a few hours after treatment, while for others it starts 24 hours later. After a person has had a few treatments, they may connect certain sights, sounds or smells with treatment and feel nauseated when they experience them. This is known as anticipatory nausea or vomiting and is more common in people receiving chemotherapy.
Cancer treatments may cause constipation and/or diarrhoea. These bowel changes occur for various reasons.
This is when your bowel motions are infrequent and difficult to pass. It can be caused by different factors including: regularly taking opioid medicines; having a diet low in fibre; not getting enough exercise; not having enough fluids to drink (dehydration); or having a low overall food intake.
This means your bowel motions are watery, urgent and frequent. You may also get abdominal cramping, wind and pain. Cancer treatment, medicines, infections, reactions to certain foods and anxiety can all cause diarrhoea.
The tips below may help you manage diarrhoea. You may also want to consider using oral rehydration drinks, e.g. Gastrolyte, to replace lost electrolytes. Ask your pharmacist for instructions on using these products. If these don’t work, ask your doctor to prescribe anti-diarrhoea medicines.
Rest as much as possible as having diarrhoea can be exhausting.
To find out more about managing diarrhoea, call the National Continence Helpline on 1800 33 00 66. Continence nurses offer confidential advice and have pamphlets on strengthening exercises that may help you ‘hold on’.
Fibre is found in cereals, fruits and vegetables. It is made up of the indigestible parts or compounds of plants, which pass mostly unchanged through the body. It helps to keep the digestive system healthy. There are different types of fibre.
This is found in the skin of fruits and vegetables; wholegrains and cereals; fibrous vegetables such as carrots and celery; and nuts and seeds. Insoluble fibre helps to absorb water and make stools bulkier, which can help if you have constipation.
This is found in oats; barley; rye; legumes (lentils, kidney beans, chickpeas); peeled fruits and vegetables; avocado; and soy milk and soy products. Eating more soluble fibre can help if you have diarrhoea.
Chemotherapy or radiotherapy to the abdomen or pelvic area can irritate your intestines, leading to abdominal discomfort or more wind (gas) than usual.
Colitis is the inflammation of the inner lining of the large bowel (colon and rectum). Proctitis is the inflammation of the rectum. These conditions may occur after external or internal radiotherapy to the pelvic area. The severity of either colitis or proctitis depends on the dose and frequency of radiotherapy, and the size of the tumour.
These conditions may make some people feel the need to empty their bowels more often, perhaps without much result. Straining can cause discomfort, and there may be some blood or mucous in bowel motions. Diarrhoea, nausea and vomiting are also common. These symptoms are usually temporary and may last for up to eight weeks after radiotherapy finishes.
This may occur after chemotherapy or radiotherapy to the abdomen or pelvic area. You may experience some abdominal discomfort (like cramps or wind pain), episodes of fluid and pale bowel motions, and more wind than usual. These changes usually improve 1–2 weeks after treatment ends. Speak to your doctor if your symptoms last longer.
Some cancers and treatments can cause heartburn, which is a burning sensation in the upper chest, oesophagus and/or throat. It’s caused by the contents of the stomach coming back up into the oesophagus (reflux).
Heartburn may make you feel too uncomfortable to eat much, which could lead to weight loss. If the tips below don’t relieve heartburn, let your doctor know as medication may help.