Radiotherapy

Radiotherapy, or radiation therapy, uses radiation to kill cancer cells. It works slowly: it takes days or weeks of treatment, and cells keep dying for weeks or months afterwards. Most often a machine aims beams at the cancer from outside the body, and this page mainly describes that. Other types place small radioactive pieces inside the body near the cancer, or use a radioactive liquid.

Radiotherapy may be used to try to cure a cancer, to help other treatments such as chemotherapy work better, or to lower the chance of cancer coming back after surgery. When a cure is not possible it can relieve symptoms such as pain. The type depends on the cancer and your health.

Planning comes first. You meet the team, then have a scan to show where the cancer is and how big it is. Small ink marks go on your skin so the same area is treated each time. For the head, neck, arm or leg you may have a plastic mask or mould.

External radiotherapy goes like this:

1. You lie on a table, or sit in a special chair. Harmless coloured lights line you up with your marks.
2. The therapists watch from outside the room, and you can talk to them through a speaker. Keep still and breathe normally.
3. The machine moves around you but does not touch you. The beam is on for about 1 to 5 minutes, and you cannot feel, hear, see or smell it.
4. If you feel sick or uncomfortable, say so: the machine can be stopped at any time. You then go home soon afterwards.

Most people are treated once a day, five days a week. If radiotherapy only eases symptoms, one session may be enough. After implants you may need a few days in hospital and to avoid close contact with others for a short time.

Effects build up over the weeks. Look after your skin: wash daily with your usual soap and pat dry, moisturise, and avoid shaving, heat or cold packs on the area. Rest when tired and try short walks. Tell the team about any soreness or skin changes.

Contact your team promptly if:

• Diarrhoea has not improved after a few weeks, or there is blood in your poo
• You suddenly feel very tired and out of breath
• You have pain or swelling in an arm or leg

Radiotherapy also affects healthy cells in the treated area. Side effects depend on that area and vary a great deal, and many can be treated or prevented. They can include:

• Sore, red or darker skin
• Tiredness, sometimes lasting weeks
• Hair loss in the treated area, usually regrowing
• Nausea and loss of appetite
• A sore, dry mouth and taste changes, if the head or neck is treated
• Diarrhoea, if the tummy or pelvis is treated

Later effects can include arm or leg swelling (lymphoedema), long-term dry mouth, changes to sex and fertility, and sometimes permanent hair loss. Over the years it may slightly raise the risk of another cancer, but the benefits generally outweigh this.

Results are not immediate, as cancer cells keep dying for weeks or months after the last session. What radiotherapy can achieve depends on the cancer, so ask whether the aim in your case is to cure, to control or to ease symptoms, and what follow-up to expect.