Radiotherapy

Radiotherapy is a common from of cancer treatment. Radiotherapy uses high energy, ionising radiation, known as radioactivity. Along with surgery, radiotherapy is another important form of treatment of localised cancer.

Radiotherapy destroys cancer cells and shrinks tumours by damaging the structure of dividing cells. Cancer cells typically divide faster than in normal tissue and so they are particularly vulnerable to radiotherapy.

Radiotherapy is used to destroy malignant tumours, boost the outcomes of surgical or other treatment (adjuvant therapy), alleviate symptoms and reduce metastases. About half of cancer patients receive radiotherapy at some stage in their treatment.

Radiotherapy is usually aimed directly at your tumour or metastases. With the treatment of widely distributed cancer, radiotherapy may sometimes be given for the whole of the upper body.

Radiotherapy can be given externally by a machine or internally by introducing a radioactive source into the body in different ways. There are a variety of methods of internal radiotherapy.

With radioisotope therapy or radiopharmaceutical therapy a radioactive medicine is introduced into the body intravenously or orally. The radioactive medicine directly affects the tumour and healthy tissue is harmed only slightly. For instance, radioiodine used to treat thyroid cancer is one form of radioisotope therapy.

If the cancer is localised, the choice between surgery and radiotherapy depends on the effectiveness of the treatment and its drawbacks. The importance of radiotherapy in cancer treatment has increased in particular with the development of conservation treatment methods.

Combining radiotherapy and surgery

Radiotherapy can be given either before or after surgery. For instance, if surgery is not sufficiently extensive or there is a major risk of tumour recurrence, treatment is usually supplemented by giving radiotherapy after surgery. Before surgery, radiotherapy may be used to reduce a tumour.

Combining radiotherapy and chemotherapy

The most effective way to combine radiotherapy and chemotherapy is to give them at the same time because they reinforce one another’s effectiveness. This is called chemoradiotherapy. It has improved treatment outcomes in many types of cancer, such as with certain lung cancers and cancers of the head and neck areas. The simultaneous use of chemotherapy nevertheless increases the side effects of radiotherapy.

Having radiotherapy

Planning radiotherapy takes into account not only your tumour but also information on the possible spread of the cancer.

Radiotherapy is completely painless and is targeted directly at the tumour or metastases. Radiotherapy is usually divided over a 2 – 8 week period. It is generally provided in small single daily doses five days a week.

Each treatment takes a few minutes. Dividing radiotherapy into several small parts reduces the harm caused to healthy tissue and improves the effectiveness of the therapy.

Patients usually go about their lives as normal during the period of treatment. In some cases accelerated radiotherapy may be given instead of phased radiotherapy. Radiotherapy is often a well-tolerated form of treatment, but it does have side effects.

Side effects of radiotherapy

Radiotherapy affects normal cells in the body and not only cancer cells. The impact on healthy tissue depends for the most part on the size of the radiation dose, the duration of treatment and what part of the body receives radiation. Adverse side effects only appear in the area of your body where the radiation is applied.

The side effects of radiotherapy may already appear during the treatment period, immediately after treatment or later, even after some years. The immediate side effects of radiotherapy are quickly apparent in dividing tissue such as in the skin, mucous membranes and bone marrow. Most side effects can nowadays be effectively prevented and treated.

Below we list the most common side effects of radiotherapy. You will be able to get more detailed information on the side effects and their treatment from the medical staff treating you.

Damage to the mouth and pharynx mucosa

Nearly all patients who receive radiotherapy to the head and neck area suffer damage to their mouth and pharynx mucosa. This is painful, makes it difficult to eat, is prone to infection and endangers dental health. Radiotherapy given to the area of the saliva glands may also cause dry mouth.

Damage to the mucosa in your mouth can be treated with preventive dental care, by treating infections, using painkillers and ensuring that you get sufficient nutrition.

Intestinal damage

Radiotherapy to your intestinal tract easily produces immediate side effects. Radiation given in the abdominal and pelvic area can cause nausea, diarrhoea and irritation of the bowel and rectal area.

The degree of damage depends on the composition of the area being treated and the size of the single and total dosage of radiation. Chemotherapy given at the same time increases and complicates the side effects. Radiotherapy given to the oesophagus can bring about a feeling of burning below the sternum, as well as pain and difficulty swallowing.

Skin

Following radiotherapy your skin may become reddened and peel. Skin redness may begin after 2 – 3 weeks and peeling generally after 4 – 5 weeks after the start of radiotherapy. Your skin may also become darker. It is important to protect the skin area under radiotherapy from sunlight, as your skin remembers the dose of radiotherapy it receives for your entire lifetime.

Bone marrow

Blood cells are produced in the bone marrow contained in your larger bones. Radiotherapy given to the pelvic and spinal area may cause a drop in white blood cell, blood platelet and haemoglobin counts. This is usually temporary and your blood count will gradually improve.

External genital and bladder irritation

If a woman’s vulva and mucous membrane areas are given radiotherapy it may cause soreness. The areas are painful and may become infected.

Acute bladder irritation from radiotherapy occurs in the treatment of bladder cancer, endometrial cancer or prostate cancer. In this situation you feel a frequent need to urinate, there may be blood in your urine and you may have a distended lower stomach. Urinating may also be painful.

Radiotherapy sequelae

Late side effects of radiotherapy may occur in organs where tissue regeneration is slow. The doctors and physicists planning your radiotherapy know the sensitivity to radiation of different organs, and plan treatment so that late side effects can be avoided. But sometimes patients do experience late side effects from radiotherapy.

The most common late effect lung symptom is radiation-induced pneumonitis. This may occur after lung tissue has been subject to radiotherapy. The symptoms include cough, shortness of breath and fever. Radiation-induced pneumonitis occurs 1 – 6 months following radiotherapy. Cortisone is used to alleviate the symptoms. The symptoms usually disappear completely.

Radiation induced pulmonary fibrosis is another late effect that may occur in the lungs.

Patients receiving brain radiotherapy may experience a syndrome including fatigue and headaches 2 – 6 months after treatment. Radiotherapy can also cause heart and blood vessel damage, which years or decades later may lead to the development of arterial disease.

 

Sources

Joensuu, Heikki; Jyrkkiö, Sirkku; Kellokumpu-Lehtinen, Pirkko-Liisa; Kouri, Mauri; Roberts, Peter J. & Teppo, Lyly (toim.) (2013) Syöpätaudit. Helsinki: Kustannus Oy Duodecim.

Suomen Syöpäpotilaat ry. Ohjeita sinulle, joka saat sädehoitoa. Helsinki, 2015.

Suomen Syöpäpotilaat ry. Selviytyjän matkaopas. Helsinki, 2014.