Radiation Therapy for Hodgkin Lymphoma

Radiation therapy uses high-energy rays (or particles) to destroy cancer cells. Radiation therapy is part of the treatment for most people with Hodgkin lymphoma (HL). It's especially useful when HL is only in one part of the body.

For classic Hodgkin lymphoma, radiation is often given after chemotherapy, especially when there's a large or bulky tumor mass (usually in the chest). Chemotherapy or radiation alone would probably not cure the lymphoma, but both treatments together usually do.

Radiation therapy can also be used by itself to treat some cases of nodular lymphocyte-predominant Hodgkin lymphoma (NHLPL).

Radiation therapy is often very good at killing HL cells. But over the years as it has become clear that chemotherapy also works very well. Today, doctors tend to use less radiation and lower doses of radiation because of its possible long-lasting side effects. (See below.)

How is radiation therapy given?

To treat HL, carefully focused beams of radiation are delivered from a machine. This is called external beam radiation.

Before treatments start, the radiation team takes careful measurements to determine the angles for aiming the radiation beams and the dose needed. This planning session, called simulation, usually includes getting imaging tests such as CT or PET scans. Casts, body molds, and head rests may be made to hold you in the same position for each treatment. Blocks or shields may be made to protect other parts of your body. You may be asked to hold your breath for a short time. The goal is to focus the radiation on the cancer to limit the affect on healthy tissues.

Most often, radiation treatments are given 5 days a week for several weeks. The treatment is a lot like getting an x-ray, but the radiation is stronger. Each treatment lasts only a few minutes, though the setup time – getting you or your child into place – usually takes longer. The treatment is painless, but some younger children might still need to be sedated to make sure they don’t move during the treatment. Modern imaging tests can pinpoint the sites of HL very precisely, which helps doctors aim the radiation only at the lymphoma while sparing nearby normal tissues. This can help limit side effects.

 

Involved site radiation therapy (ISRT)

Many doctors prefer this newer approach to radiation therapy when treating HL. In ISRT, the radiation is aimed only at the lymph nodes that originally contained lymphoma, as well as any nearby areas the cancer extended into. This shrinks the size of the treatment area (or field) and helps spare nearby normal tissues and organs from getting radiation.

Involved field radiation therapy (IFRT)

This was the preferred form of radiation therapy for HL in the past, but it's now largely being replaced by ISRT. In this technique, only the lymph node regions that have HL are treated, but this includes larger treatment areas than ISRT does. (This can increase the risk of radiation reaching nearby organs.) 

Extended field radiation

This is rarely done today, but radiation used to be given to the major lymph node areas that contained lymphoma, as well as the surrounding normal lymph node areas. This was done just in case the lymphoma had spread, even though the doctors could not actually detect it in these areas. This is called extended field radiation.

• If the lymphoma 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 (belly).
• 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 irradiation.

Because nearly all patients with HL are now treated with chemotherapy, 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, see High-dose Chemotherapy and Stem Cell Transplant.

Possible side effects of radiation therapy

The side effects of radiation therapy depend on where the radiation is aimed.

Some possible short-term effects include:

• Skin changes in areas getting radiation, ranging from redness to blistering and peeling 
• Feeling tired
• Dry mouth
• Nausea
• Diarrhea

Radiation given to several areas, especially after chemotherapy, can lower blood cell counts and increase the risk of infections.

Radiation therapy can also have long-lasting effects, including:

• An increased risk of another cancer in the part of the body that was exposed to radiation.
• Damage to the thyroid gland (from radiation to the chest or neck), which can affect its ability to make thyroid hormone. This can lead to fatigue and weight gain.
• An increased risk of heart disease (such as heart attacks) and lung problems from radiation to the chest
• An increased risk of stroke years later after radiation to the neck
• Slowed bone growth in children. Depending on where the radiation is given, this could cause deformities or cause a child to not grow to their full height. Radiation to the lower part of the body in children and young adults could 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 beams as accurately as they can. Shields might also be placed over nearby parts of the body to protect them from the radiation. To help preserve fertility in girls and young women, the ovaries might be moved out of the way with minor surgery before radiation is given.

For more information, see Late and Long-term Side Effects of Hodgkin Lymphoma Treatment. If you or your child is getting radiation therapy, be sure to talk to your doctor about the possible long-term side effects. Hodgkin lymphoma can be cured and long-term side effects are a very real concern.