Radiotherapy and side effects on nutrition

Radiotherapy, or radiation therapy, is commonly used for the treatment of cancer and uses high energy x-rays or other types of radiation to damage cancer cells so they are unable to multiply.

There are two types of radiotherapy:

• the external radiotherapy uses a machine outside the body to send radiation toward the tumour. The machine, a linear accelerator, is located at a certain distance from the body and directs its radiation bundle in the specific body region affected by the tumour. During the treatment, cancer patients can have a normal life without any radiation contamination risks for others;
• the internal radiotherapy uses a radioactive substance sealed in needles, seeds, wires or catheters that are placed directly into or near the malignant tissue. The internal radiotherapy requires that cancer patients stay isolated until the radioactive substances are naturally eliminated.

Radiotherapy can cure some cancers and reduce the risk of the cancer returning after it has been removed by surgery. It is also used to reduce the symptoms of cancer.

Radiotherapy may be used alone or in combination with surgery or chemotherapy. Before surgery, radiotherapy is useful to shrink a tumour while, after surgery, the treatment helps destroy any cancer cells that may remain in the area.

Because radiotherapy inhibits growth and division of all types of cells, normal and malignant, it can affect healthy cells in the treatment area, and side effects may occur. Generally, side effects can be:

• acute, generally appearing at the beginning of the treatment and easing off or gradually disappearing at its end;
• delayed, appearing also after the treatment and, generally, more severe.

These side effects are unavoidable, depending mostly on the radiation dose and the part of the body that is treated. They can be controlled with specific medical treatments and may be helped by appropriate nutrition support and changes to the diet.

If you have any of these side effects or are worried about the side effects of radiotherapy talk to your doctor or radiotherapy unit staff.

Part of the body affected by cancer	Possible radiotherapy side effect
General	tiredness (which can lead to a decrease in appetite and a reduced desire to eat)
Head and neck	anorexia taste changes dry mouth sore mouth and gums swallowing problems infection
Chest	infection in the oesophagus swallowing problems oesophageal reflux (a backwards flow of the stomach contents into the oesophagus) nausea vomiting
Abdomen or pelvis	diarrhoea nausea and vomiting discomfort around the back passage (rectum) fistula (holes) in the stomach or intestines. Long-term effects can include narrowing of the intestine, chronic inflammation in the lining of the intestines, poor absorption, or blockage in the stomach or intestine.
Gastrointestinal tract	Appearing early in treatment and last only a short time: irritation of the mouth, tongue and throat lactose intolerance nausea vomiting diarrhoea Appearing months after therapy and longer lasting: dry mouth stricture or narrowing of the oesophagus malabsorption of nutrients abdominal discomfort diarrhoea

For more information about common side effects and how to cope with them go to the Cancer side effects section.

Source: National Cancer Institute, Nutrition in cancer Editorial Board

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