Radiation therapy for Hodgkin disease

Radiation therapy uses high-energy rays (or particles) to destroy cancer cells or slow their rate of growth.

When radiation is used to treat Hodgkin disease, it is done with a carefully focused beam of radiation, delivered from a machine outside the body. This is known as external beam radiation. It is most useful when the disease is localized to one part of the body. Radiation is also used with chemotherapy when the Hodgkin disease involves a large or bulky tumor mass, usually in the chest. In this circumstance, the chemotherapy alone or radiation alone will not cure the patient, but both treatments together are usually effective in getting rid of the disease.

The main drawback of external beam radiation is that it only kills Hodgkin cells in the precise area where the radiation has been given. So, if Hodgkin cells are hidden in other areas of the body, radiation alone is not likely to be successful.

Involved field radiation

For involved field radiation, only the lymph node areas that contain Hodgkin disease are treated. This is the preferred form of radiation therapy when it is used along with chemotherapy. Chemotherapy is given first, then involved field radiation is given to areas that were initially involved.

Involved field radiation therapy may also be used by itself to treat some cases of nodular lymphocyte predominant Hodgkin disease.

Extended field radiation

In the past, the major lymph node areas that contained Hodgkin disease, as well as the surrounding "normal" lymph node areas, were usually treated with radiation, just in case the Hodgkin disease had spread, even though the doctors could not actually detect it in these areas. This is called extended field radiation.

• If the Hodgkin disease was in the upper body, radiation was given to the mantle field, which included lymph node areas in the neck, chest, and under the arms. Sometimes this was extended to also include lymph nodes in the upper abdomen.
• Inverted Y field radiation therapy included the lymph nodes in the upper abdomen, the spleen, and the lymph nodes in the pelvis).
• When inverted Y field radiation was given together with mantle field radiation, the combination was called total nodal radiation.

Because nearly all patients with Hodgkin disease are treated with chemotherapy now, extended field radiation is seldom used any more.

Total body irradiation

People who are getting a stem cell transplant may get radiation to the whole body along with high-dose chemotherapy, to try to kill lymphoma cells throughout the body. For more information on this procedure, see the section, "High-dose chemotherapy and stem cell transplant."

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. This is described in the section, "What happens after treatment for Hodgkin disease?"

In children, another possible side effect of radiation is the failure of bones to grow normally. Depending on where the radiation is given, this could result in deformities or a lack of growth to full height. Doctors use as little radiation as possible in children.

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 pills containing thyroid hormone can help with this. Radiation to the chest also increases the risk of heart disease (such as heart attacks), while radiation to the neck may increase the risk of stroke many years later.

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 to hit the cancer and limit exposure of the nearby normal tissues. Ask your doctor about the possible side effects of radiation therapy.

Monoclonal antibodies for Hodgkin disease

Antibodies are proteins made by the body's immune system to help fight infections. Man-made versions, called monoclonal antibodies, can be designed to attack a specific target, such as a substance on the surface of lymphocytes (the cells in which lymphomas start).

Some monoclonal antibodies are now being used to treat Hodgkin disease.

Brentuximab vedotin (Adcetris™): This drug is an anti-CD30 antibody attached to a chemotherapy drug. Hodgkin disease cells usually have the CD30 molecule on their surface. The antibody acts like a homing signal, bringing the chemo drug to the lymphoma cells, where it enters the cells and causes them to die when they try to divide into new cells.

This drug has been shown to help many people whose Hodgkin disease has come back after other treatments, including a stem cell transplant (see next section), as well as people who can't have a stem cell transplant. It is also being studied to see if it can be given with chemotherapy and if it is helpful if it is given earlier in the course of the disease.

Brentuximab is given as an infusion into a vein (IV) every 3 weeks. Common side effects include nerve damage (neuropathy), low blood counts, fatigue, fever, nausea and vomiting, infections, diarrhea, and cough.

Rituximab (Rituxan®): This is an antibody that attaches to a substance called CD20 found on some types of lymphoma cells. This attachment seems to cause the lymphoma cell to die. Rituximab may be used in the treatment of nodular lymphocyte predominant Hodgkin disease (NLPHD), often along with chemotherapy and/or radiation therapy.

The treatments are given as intravenous (IV) infusions in the doctor's office or clinic. When it is used by itself to treat lymphoma, it is usually given once a week for 4 weeks, which may then be repeated several months later. When it is combined with chemotherapy, it is most often given on the first day of each chemo cycle.

Common side effects are usually mild but may include chills, fever, nausea, rashes, fatigue, and headaches. Rarely, more severe side effects occur during infusions, such as trouble breathing and low blood pressure. Even if these symptoms occur during the first rituximab infusion, it is very unusual for them to recur with later doses. Rituximab can cause hepatitis B infections that were dormant (inactive) to become active again, sometimes leading to severe liver problems or even death. For this reason, your doctor may check your blood for signs of an old hepatitis infection before starting this drug. This drug may also increase a person's risk of certain infections for several months after the drug is stopped.