To treat Hodgkin disease, a carefully focused beam of radiation is delivered from a machine outside the body. This is known as external beam radiation. Most often, radiation treatments are given 5 days a week for several weeks. Before the treatments start, the radiation team takes careful measurements to determine the dose needed and the correct angles for aiming the radiation beams. The treatment is much like getting an x-ray, but the radiation is more intense. Each treatment lasts only a few minutes, although the setup time – getting you or your child into place – usually takes longer. Radiation itself is painless, but some younger children may need to be sedated to make sure they don’t move during the treatment.
Radiation therapy is often very good at killing Hodgkin disease cells. Decades ago, this was the best treatment available for Hodgkin disease, but over the years doctors realized it could lead to long-term side effects. As it became clear that chemotherapy was also effective, doctors began to use less radiation. Today, if radiation therapy is used, only the involved areas are treated with radiation to try to limit side effects.
Radiation Treatment Approaches
The two main types of radiation therapy are extended field radiation and involved field radiation.
Extended field radiation targets the diseased lymph nodes and surrounding healthy lymph nodes. Extended-field radiation is rarely given in combination with chemotherapy. Specific subtypes of extended field radiation are used depending on the location of the disease:
- If HD is above the diaphragm, “extended field radiation” is delivered to the neck, chest, and under arms (called the mantle field). Radiation is sometimes expanded to include lymph nodes in the upper abdomen.
- If cancer is below the diaphragm, an "inverted Y" field is sometimes used, in which radiation is directed at lymph nodes in the upper abdomen, spleen, and pelvis.
- Inverted Y-field radiation therapy combined with mantle-field radiation is called total nodal radiation.
Involved field radiation targets only lymph node regions that are known to have cancer, not the adjacent, uninvolved lymph node regions. Involved-field radiation is usually given after several rounds of chemotherapy.
In general, recent research suggests that extended-field radiation adds little survival advantage and carries a greater risk of serious side effects. Involved-field radiation is now becoming the preferred method. Some researchers recommend that involved-field radiation therapy plus chemotherapy should become the standard treatment for patients with early-stage Hodgkin’s disease who have a good prognosis. More research is needed before standard practice guidelines can be implemented.
Side Effects
The most common side effects of radiotherapy during and just after treatment are:
- Reddening of the skin in the treatment area
- Tiredness
- Loss of hair in the treatment area
Your skin may look slightly sunburnt in the area that has been treated. Don't use any creams or lotions unless the radiotherapy centre has given them to you. There is detailed information about skin care during radiotherapy in the main radiotherapy section. Tiredness usually comes on towards the end of a course of treatment. It may take some weeks or even months to go completely after your course of treatment is over. There is more about radiotherapy tiredness in the radiotherapy section.
Other side effects of radiotherapy vary depending on which part of the body is being treated. If your treatment is to the abdomen, you may feel sick or have diarrhoea. These effects can get worse towards the end of your treatment and will then gradually clear up after it has finished. If you are having extended field radiotherapy, you will probably find that tiredness and sickness are the most troublesome side effects. Ask your doctor for anti sickness medicines to take before your treatment. They do help.
Possible Side Effects
The side effects of radiation therapy depend on where the radiation is aimed. Some people have skin changes similar to sunburn, which slowly fades away. Other possible short-term side effects include fatigue, dry mouth, nausea, or diarrhea. Radiation given to several areas, especially after chemotherapy, can lower blood cell counts.
Long-term side effects: Radiation therapy can also have long-term side effects. The most serious of these is the development of another cancer in the part of the body that was exposed to radiation. Other possible long term problems include:
- Risk of a second cancer
People treated for Hodgkin lymphoma with radiotherapy have an increased risk of developing another cancer later in life. The highest risk is of breast cancer, caused by radiotherapy to the chest. Doctors usually only treat the centre of the chest these days, rather than a large T shape across the chest and shoulders, as they used to do. The total radiation dose used is lower. So the risk of a second cancer is lower than it used to be. For some people it may not be necessary to have radiotherapy after the chemotherapy. Your doctor will discuss with you the different treatment options in your case.
Children treated with radiotherapy for Hodgkin lymphoma also have an increased risk of developing another cancer later in life. For some children it may not be necessary to have radiotherapy after chemotherapy treatment. Researchers and doctors are currently doing research trials to see which children need radiotherapy after chemotherapy and which children don't need it. Your child's doctor will discuss this with you and your child. If you had radiotherapy for lymphoma as a child and are worried about your possible cancer risk, you can make an appointment to see your lymphoma specialist to talk about this issue. Or if you've lost touch with your specialist, you can see your GP.
Women who have had radiotherapy to the chest for Hodgkin lymphoma, including as a child, may have yearly breast screening from 8 years after treatment, or from age 25 years (whichever is later). This is the group with the largest cancer risk at the moment. It is possible for men treated with radiotherapy to the chest to get breast cancer, but it is much, much rarer. For men and women who had chest radiotherapy, there is also a smaller risk of thyroid cancer, lung cancer, or cancer of the food pipe (oesophagus). If you are at all worried, speak to your specialist. - Heart problems
Radiotherapy to the chest for Hodgkin lymphoma can increase the risk of heart disease in later life. Nowadays, doctors use reduced treatment fields and doses as much as possible to reduce any effects on the heart. But it is important to be aware of this side effect, particularly if there is heart disease in your family. You can help to reduce your risk by having a healthy diet, exercising regularly, and not smoking. - Changes in the way your thyroid gland works
After radiotherapy to the neck for Hodgkin lymphoma, some people can develop a condition of the thyroid gland, called hypothyroidism. The thyroid gland stops producing enough thyroid hormones and people need to take thyroid hormone (thyroxine) tablets. - Infertility from inverted Y radiotherapy
If you have inverted Y radiotherapy, you may become infertile. - Inflammation of the lungs (pneumonitis)
Radiotherapy to the chest can cause inflammation of the lungs called radiation pneumonitis. The inflammation can cause a long term cough, and sometimes breathlessness.
Radiation to the chest or neck can damage the thyroid gland, which can affect its ability to make thyroid hormone. This can lead to fatigue and weight gain. Treatment with thyroid hormone pills can help with this. Radiation to the chest also increases the risk of heart disease (such as heart attacks) and lung problems, while radiation to the neck may increase the risk of stroke many years later.
In children, radiation that reaches the bones may slow their growth. Depending on where the radiation is given, this could result in deformities or a lack of growth to full height. Radiation to the lower part of the body in children and young adults might also affect fertility later in life.
To reduce the risk of side effects, doctors carefully calculate the exact dose of radiation needed and aim the radiation beam as accurately as they can. Shields may also be placed over nearby parts of the body to protect them from the radiation. In girls and young women, the ovaries may be moved out of the way with minor surgery before radiation is given to help preserve fertility.
Complications of Radiation
- Fatigue. Fatigue is significant and chronic in many survivors. It is more highly associated with intensive chemotherapy, but it also may be a late response to radiation treatment.
- Heart Disease and Stroke. Radiation is associated with a future risk of heart disease, which includes atherosclerosis (hardening of the arteries) and diseases of the heart valves. Lower doses pose less risk. Recent research suggests that adults who survived childhood Hodgkin’s disease have a four times higher risk of having a stroke than healthy patients.
- Impaired Growth in Children. Children and adolescents are at special risk for impaired bone growth.
- Infections. Infections may be a particular problem with radiation combined with chemotherapy. All patients should be vaccinated against the bacteria that often cause pneumonia and meningitis, and against the influenza virus.
- Infertility. Radiation therapy to the pelvic area can adversely affect later fertility in women and men. Such negative effects may be worse in women; sperm usually recover within 5 years.
- Secondary Cancers. Second cancers (such as breast, stomach, lung, melanoma) may develop later in areas within or at the edge of the radiation area. Thyroid, respiratory tract, and digestive tract secondary cancers may affect patients who were treated as children. Lung cancer in survivors is highly associated with smoking after treatment, and no survivor should smoke. The risk for breast cancer increases significantly in women who receive chest radiation. The risk can persist for 25 years or more after radiotherapy, and lifetime monitoring (including frequent mammograms) is essential.
- Thyroid Disorders. Hypothyroidism (underactive thyroid) occurs in a number of patients treated with radiation treatments. There is also a 5% chance for hyperthyroidism (overactive thyroid).