Unwanted effects of treatment

Most cancer treatments damage healthy cells as well as cancer cells; this is the main cause of side effects. Side effects vary depending on the treatment used and everyone reacts differently. Chemotherapy targets rapidly dividing cells, hence the lining of the mouth and digestive tract, the hair, skin and bone marrow are all affected. Radiotherapy damages normal cells in and around the treated area. Biological therapies may also cause side effects. Most side effects disappear within a few weeks of treatment finishing.

Leukaemia treatment often involves having several types of drug at the same time, possibly in combination with radiotherapy, so it can be difficult to know which treatment is causing what side effect. Side effects from high dose chemotherapy or total body irradiation (TBI) given in preparation for a stem cell transplant are more severe than those from standard chemotherapy or radiotherapy regimens.


Chemotherapy and radiotherapy can cause tiredness making people feel weak and lethargic. Frances felt ‘tired to a level that I never thought was possible’. Some had difficulty sleeping at night despite their tiredness, or found even reading too much effort. Some people said that the tiredness they felt during treatment was the same as the tiredness they had felt beforehand. Tiredness could persist long after treatment and some people had to adapt their lifestyle.

The digestive tract

Nausea and vomiting associated with chemotherapy can usually be reduced or avoided with anti-sickness drugs. Some people had expected to feel sick but were pleasantly surprised when they weren’t; several felt nauseous but did not vomit.

Oral chemotherapy causes only mild side effects and some people managed without anti-sickness medication. On rare occasions hospital staff forgot to give the anti-sickness drugs, causing vomiting. Some found the anti-sickness drugs didn’t always work so they vomited occasionally. Ian said it took time to find the right dose for him. John found anti-sickness injections more effective than tablets, and that they worked best shortly before eating.

Treatment with the biological therapy alemtuzumab (MabCampath) made Glyn feel sick – he vomited in the car on the way home. People taking imatinib (Glivec) for chronic myeloid leukaemia (CML) were advised to take it with food to avoid nausea. Having initially felt sick after taking it in the morning, one woman subsequently took it at bedtime.

Some people had diarrhoea as a side effect of chemotherapy. Elizabeth 'lost all her dignity' when she didn’t make it to her commode in time. One man was horrified when the nurse asked for a sample. ‘Ace’ wasn’t sure whether his diarrhoea was a treatment side-effect or due to a bug circulating in the hospital. Some people had painful constipation, others indigestion.

Painful ulcers or blisters in the mouth and digestive tract were common after chemotherapy or radiotherapy, and people were given mouthwashes and ointments. Morphine was often given to reduce the pain and sucking ice cubes could be soothing. Claire had to spray artificial saliva into her mouth. Dental problems also occurred.

Eating difficulties

Eating is important in aiding recovery from the toxic effects of cancer treatments, yet side effects can make eating difficult. Nausea and vomiting may reduce the appetite and make it difficult to keep food down. Painful blisters in the mouth and oesophagus can make swallowing anything other than soft food problematic. Chemotherapy can also damage taste buds making foods taste metallic or bland and therefore seem unappealing. Even the sight or smell of food can be off-putting.

Hospital staff tried to encourage people to eat. Steroids were used to build up strength and increase appetite and hence weight (see ‘Supportive treatments’). Family and friends brought in home-cooked food or supermarket ready meals, which might seem more appetising than hospital food. Elizabeth refused attempts by the staff to feed her but allowed her mother to feed her soup. Neil had a craving for pizza and asked the nurses to get one, which kick-started his appetite. Aley asked for baby foods.

Some people didn’t eat for days or weeks. High energy drinks were offered in an attempt to build them up. Nurses told several that if they didn’t eat they would be fed artificially through a tube. This threat made some people eat enough to keep their weight above the critical level; others were less fortunate. Elizabeth said the nutritional fluid felt too rich but it kept her alive. Aley said his feeding tube came out when he vomited.

As a result of weakness and eating difficulties many people lost weight and muscle tone. Aley said he lost 23 kilos; his brother who came from Pakistan to visit him was upset to see him so thin. Elizabeth said that the clothes she had worn on entering hospital dropped to the ground when she put them on to leave.

Hair and skin

Hair loss may occur after taking certain chemotherapy drugs or having radiotherapy to the head. The resulting changes in appearance may be upsetting and difficult to deal with (see ‘Hair loss and body image’). Some people taking biological therapies or certain chemotherapies developed a rash; an antihistamine sometimes prevented this. Mike said he was given various ointments but nothing really worked. A few people said skin had peeled off from their legs, arms, back, hands or feet after chemotherapy.


Chemotherapy damages normal blood cell production causing shortages which can be corrected by blood transfusions or drugs that stimulate the bone marrow (see ‘Supportive treatments’). People taking interferon (a biological therapy) often had flu-like symptoms.

Less common treatment side effects included conjunctivitis, sweats, uncontrollable shivering (rigors), numbness, water retention, muscle twitches or stiffness, and joint pain. Some people having biological therapies or relatively mild chemotherapy experienced no side effects.
Last reviewed: December 2018.
Last updated: July 2012.

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