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Radiotherapy, or treatment using radiation, uses high energy X-rays to kill cancer cells. It is also used to treat non-cancerous tumour. 4 out of 10 people affected with cancer are given radiotherapy.

All cancers are not radiosensitive, that is they do not respond to radiation, but others respond really well and few need a combination of both radiotherapy and chemotherapy. Once the cancer is found to be radiosensitive, then depending on the size, site and extent of spread of cancer, the duration and courses are adjusted.

Radiotherapy may be used:

• to cure an illness - by destroying a tumour
• to control symptoms - to relieve pain
• before surgery - to shrink a tumour to make it easier to remove
• after surgery - to destroy small amounts of tumour that may be left

Some non-cancer diseases, such as thyroid diseases and some blood-related disorders are also treated with radiotherapy.

There are two types of radiotherapies, external and internal.

1. External radiotherapy is given from outside the body, using X-rays, electron and rarely, protons. They are usually given once a day as a course of treatment over a number of days or weeks.
2. Internal radiotherapy uses a radioactive material which is mixed in liquid and drank by the patient or injected into the system or near the tumour.

Radiotherapy is usually given as a course of treatment that lasts for a number of days or weeks. Most people who have radiotherapy to treat a serious condition, such as cancer, have five treatments a week (one treatment a day, Sunday to Thursday) with a break at the weekend. Taking a break allows the normal, non-cancerous cells to recover.

The cancer cells are surrounded by healthy cells. Although the radiation is aimed at the cancer site, it can damage the surrounding tissues. The radiation can be toxic to normal, healthy cells. The common side effects of radiotherapy include:

• sore skin
• tiredness
• feeling sick
• dry mouth
• loss of appetite
• diarrhoea
• hair loss
• discomfort on swallowing
• a lack of interest in sex
• stiff joints and muscles

There are few long term side effects which you should ask your doctor and be prepared for beforehand.

• early menopause and infertility
• skin changes such as thickening, darkening and dimpling
• tiny pelvic fractures causing severe pain during movements
• inability to control your bowel movements
• swelling of the arms or legs