Side effects

  • Since radiotherapy not only affects the tumour, but also to some extent, healthy tissue, there is a risk of side effects. Since we humans can tolerate different amounts of radiation, the side effects vary from person to person. Many people have no side effects at all.

    Side effects of radiotherapy are often divided into early and late. Most early side effects are usually felt after two to three weeks of therapy, but they may come earlier. They do not pass immediately after the last therapy. There is often a peak shortly after radiotherapy ends, then the side effects gradually subside over a few weeks.

    Late side effects can be felt for several months, or even years, after radiotherapy ends.


    General side effects – irrespective of the radiation area

    Early side effects

    Temporary skin problems
    During radiotherapy, the skin in the treated area may react as after a severe sunburn. Typically, the skin becomes red and irritated, but itching may also occur. These problems may occur after a few weeks. Armpits, groins and other areas with creases are extra sensitive.

    When washing the treated area, dab your skin with lukewarm water and pat dry. Do not rub and avoid highly perfumed soap or deodorant. There are also ointments and creams that can reduce these side effects. Please consult your nurse or doctor on what is appropriate for you.

    Wearing loose-fitting clothes over the treated area is recommended. Use fabrics that absorb moisture and keep your skin dry, since moisture can aggravate symptoms. Make sure the treated area is not exposed to sun or wind.

    You should also avoid shaving the treated area as it irritates the skin. The hair in the treated area also stops growing after some time.
    Try eating a healthy and versatile diet. Your body needs a lot of energy and nutrition to heal the skin.

    Feeling tired is common during the therapy. Some people feel a little tired, others feel so tired that it affects their lives. Fatigue typically decreases a few weeks after therapy ends and then disappears completely.

    Physical activity can reduce fatigue. It may also help to take several short naps, rather than a long one, during the day.

    It is important to bear in mind that fatigue may have causes other than the therapy. It may be due to low blood counts, because you do not eat enough or have insomnia. You may want to consult a doctor or nurse about your fatigue.

    Some radiotherapy patients feel nauseous. Some may feel nauseous early in the therapy, others towards the end of it. If you are affected, there are effective medications to treat it.

    Late side effects

    Skin changes
    The skin in the treated area may change and feel a bit stiff and hard. Some patients have small, visible, superficial blood vessels. This is known as fibrosis. If your fibrosis causes problems, surgery may be considered.

    If you have undergone radiotherapy of an area with a lot of nerves, you may feel pain, tingling or weakness in the treated area. For example, if you have undergone radiotherapy of the clavicle, or just above, you may experience symptoms in the arm.

    Cancer and cancer treatment may change both your body and how you perceive yourself. If you are worried and depressed in the course of a cancer treatment, it can affect your libido. If you have a partner, it is a good idea to talk about how you think and feel about this. It may be a way of creating closeness and reducing the risk of misunderstandings, for example if someone feels rejected. Body contact and intimacy without sexual expectations may strengthen the relationship and restore desire.

  • Radiotherapy of the head

    Radiotherapy may affect hair growth, causing your hair to stop growing and fall off in the treated areas. This applies to all hair on your head, including eyelashes and beard. Hair growth outside the treated area is not affected. Most people find that their hair grows back a few months after therapy ends. However, with higher doses of radiation, you may lose your hair permanently. If you do lose you hair, you are eligible for a wig and false eyelashes. Please consult your contact nurse or treating doctor on what applies in your region

  • Radiotherapy of the abdominal and pelvic region

    Early side effects

    Radiotherapy for tumours in the abdominal and pelvic region may cause nausea and other stomach problems, such as diarrhoea or bloating. The risk for these problems increases when a large area of the body is being treated. If you are affected, there are effective anti-nausea medications available to combat it.

    Radiotherapy of the bladder can cause you to urinate frequently and urination may be painful. These side effects may also be reduced with medications.

    Late side effects

    A late side effect is that the bladder can be affected, which may cause incontinence. Also, the intestines may react with diarrhoea. If you are experiencing any of these problems, a physiotherapist can help you strengthen the muscles used to control the opening and closing of your bowels. There are also medications that can reduce these side effects. If this is your reality, you are eligible for free incontinence pads from your district nurse.

    Women undergoing radiotherapy of the pelvis and abdomen may have fragile mucous membranes. They may for example experience pain or bleeding during intercourse. Using a lubricant may reduce the problem. The therapy can also result in a build-up of scar tissue, which may cause narrowing of the vaginal opening and complicate a gynaecological examination, making sexual intercourse difficult. To prevent discomfort, use a dilator, a rod that you insert into your vagina. Pick it up at your home clinic. Eventually, you may need to change size.

    Radiotherapy for tumours in the abdominal and pelvic region may cause lymphedema, that is, accumulation of lymphatic fluid in, for example, a leg or an arm. The body part where the lymphatic fluid has collected may become swollen and numb or feel heavy. In order to reduce the side effects, it is important that the problems are detected early to ensure that treatment is started as soon as possible.

  • Radiotherapy of the mouth and throat

    Radiotherapy of the throat may affect your taste buds, causing alterations in your sense of taste or taste loss. These taste disturbances can make eating difficult or unpleasant. A dietitian can advise on how to customise your food so you can eat as well and as varied as possible. The sense of taste usually comes back after therapy ends, but it may take some time.

    The first sign that the mucous membrane of the throat reacts to the radiation is that it feels like a lump in your throat. The irritation can worsen and cause pain and in some cases difficulty swallowing. In these cases, you can get medications that reduce the pain, making it easier for you to swallow and brush your teeth.

    The throat problems may make eating difficult, which can result in weight loss. It is important to keep your weight during radiotherapy; you are not supposed to lose more than a few kilos. Please consult your doctor if you find that you have lost weight.

    Disorders of the oral cavity may occur because irritated mucous membranes are more vulnerable to fungi. Keeping a good oral hygiene is therefore important.

    Another side effect is reduced saliva production, which may reduce your resistance to infection. The symptoms of dry mouth can be alleviated with saliva replacement sprays or lozenges available in pharmacies. It is important to keep using these products, even after the therapy ends, as dry mouth can become a permanent problem.

    Keeping a good oral hygiene may reduce the side effects associated with radiotherapy. During the therapy, you may want to get help from a dental hygienist; please consult your treating doctor on this.