Understanding Radiotherapy

What is radiotherapy?
Radiotherapy is the use of high energy x-rays and similar rays (such as electrons) to treat disease. The aim of the treatment is to destroy the cancer cells in the area being treated. Normal cells will also be affected but they are better able to repair themselves. Radiotherapy treatment can cure some cancers and can also reduce the chance of a cancer coming back after surgery. It may be used to reduce cancer symptoms.


Types of radiotherapy
There are two main types of radiotherapy treatment: external radiotherapy and internal radiotherapy.

External radiotherapy is where a machine is used to give a dose of energy, such as X-rays, to attack the cancer cells. There are different types of radiotherapy machines, which work in slightly different ways. For a session of radiotherapy you will be asked to sit or lie in a position that allows the energy beam to be directed accurately at the cancer. This may involve lying down while the machine rotates around you, or you may be asked to sit in a chair while the beam is directed at a cancer that is near the surface of your skin (also called superficial cancer). The machine won't touch you and you won't feel any pain during the treatment. When you are settled, the therapist has to go out into a separate control room. This is for their protection from repeated exposure to radiation. In the control room they can see you via a TV monitor or through a window, and you will still be able to talk to them. The therapist then uses controls to emit radiation from the machine for a short time.

Each session of treatment usually only lasts a few minutes (although it may take several minutes to position you and the machine correctly each time). During each treatment session the radiation may be emitted several times in short bursts from different angles. This may mean that you or the machine need to be adjusted a few times during a treatment session. One reason why this may be done is that although each burst of radiation will focus on the cancer, each burst will pass through different parts of your body on the way. This aims to reduce damage to normal tissues.

Internal radiotherapy is where the source of radioactivity is put inside your body so it can get closer to the cancer. This can be done in two ways:

1. Brachytherapy

Brachytherapy allows a physician to use a higher total dose of radiation to treat a smaller area and in a shorter time than is possible with external radiation treatment. A solid source of radioactivity is put next to a tumour to give a high dose of radiotherapy. This means the effect on body tissue around the cancer is as little as possible.

Brachytherapy is used to treat cancers throughout the body, including the:

• Prostate
• Cervix
• Head and neck
• Ovary
• Breast
• Gallbladder
• Uterus
• Vagina

2. Radioisotope therapy

This is when a liquid radioactive source is put inside your body. A radioactive liquid (usually radioactive iodine) is given either as an injection into a vein or as a liquid you can drink. Radioisotope treatment can be used for thyroid, adrenal and bone cancers.

You will need to drink plenty of water during your treatment, to flush the radioactive iodine out of your system. The amount of radiation in your body will be closely monitored, and when it drops back down to a safe level you will be able to go home.

Common side effects during treatment

Not every patient experiences side effects. Usually, one or two side effects occur. Depending on which part of your body is being treated, possible side-effects immediately after radiotherapy include:

• Tiredness
• Loss of appetite
• Feeling sick and vomiting
• Skin changes – skin may become red, itchy and sometimes sore, like sunburn
• Hair loss (alopecia) – this may affect parts of the body that were treated, including head, facial hair, armpits and pubic hair.
• Mouth issues – may include mouth dryness, difficulty chewing and swallowing, and dental decay.
• Chest problems – may include coughing, shortness of breath and painful swallowing.
• Abdominal problems – may include diarrhoea, bleeding (rarely), a burning sensation when urinating, the urge to urinate more often, vaginal dryness and discomfort. If the ovaries are present and working, they may cease to work after four weeks and menopause may affect women. Patients with prior bowel disorders such as diverticular disease may find their symptoms become worse.
• Emotional symptoms - feeling low, depressed or anxious after treatment
  

Quick Notes:

• Radiotherapy is the use of precisely targeted x-rays to destroy cancer cells. It is a painless treatment given in a number of doses.
• Common side effects of radiotherapy include fatigue and skin problems such as itchiness and colour changes.
• It is important to remember that almost all side effects will disappear once treatment is completed.
• Later effects will need to be monitored along with your progress.