Unlike chemotherapy which is a systemic therapy (affecting the whole body as it is infused into the bloodstream), radiation therapy is a local therapy meaning that it only treats the area of the body where the cancer is located. Radiation therapy is often combined with chemotherapy but is sometimes used alone as the main treatment.
Radiation therapy (also called radiation or radiotherapy) uses high-energy X-rays to kill cancer cells. The X-rays cause damage to the cell's DNA (the genetic material of the cell) which makes it impossible for the cancer cell to repair itself and causing the cell to die. The radiation does not distinguish between cancerous and non-cancerous cells and therefore the surrounding healthy cells are also destroyed. Care is always taken when planning the treatment to ensure that other areas of the body are affected as little as possible. Normal cells affected by the radiation have a greater capacity to heal themselves than the lymphoma cells.
A radiation field is the area of the body which will receive the radiation therapy. To clearly outline the radiation field the skin is marked with tiny ink dots called tattoos. This ensures that the appropriate area is targeted for the radiation and that the exact same area is treated each time.
Radiation is usually confined to lymph nodes or the area immediately surrounding the lymph nodes. The radiation field is different in each person and depends on many factors including the type of lymphoma and the extent of the disease. Healthy areas are shielded from the radiation with lead shields, which block the path of any stray radiation beams and prevents them from affecting the DNA of normal cells.
Prior to your radiation therapy you may attend a planning session with a radiation technician, a nurse and several specialist doctors. At the beginning of radiation treatment, you will be carefully positioned on a treatment table, with the lead shield protection in place for the parts of the body not being treated. You must lie completely still during the treatment. Often a mould is created or certain props such as pillows or rolled blankets are used to limit movement. Above the treatment table is the large machine which delivers the radiation. The actual treatment lasts only for a few minutes and causes no pain or discomfort.
Radiation therapy is most often given on an outpatient basis. You may have to visit the hospital as many as five times per week during a course (cycle) of radiation therapy. The total dose deemed appropriate for you is divided up and given over a period of one to six weeks. Each dose of radiation is called a fraction and the radiation oncologist prescribes a total number of fractions for your specific treatment.
![]() Patient receiving radiation for NHL |
Although the radiation treatments are painless, there may be some associated side effects. These are usually limited to the area of the body receiving the radiation and may vary based on the targeted site. The most common side effects are listed in the following table. For more detailed information on the side effects of radiation therapy, see the chapter "Managing Treatment Side Effects".
| Targeted Area | Possible Side Effects |
|
Head and neck (areas affected can include the scalp, mouth and throat) |
|
|
Chest (areas affected can include the oesophagus and breasts) |
|
|
Abdomen |
|
It is possible for radiation to cause long-term side effects. The following table outlines the possible consequences of radiation given to different areas of the body. It is important to discuss these risks with your doctor if you feel concerned.
| Treatment Area | Possible Long-Term Effect | What You Can Do |
|
Pelvis or groin |
Infertility |
Ensure that the testes/ovaries are shielded from radiation if they are not the target of the treatment. If you have not yet had children, talk to your doctor about the risks associated with having children after radiation therapy. |
|
Chest and breasts |
Breast cancer |
Long-term breast cancer screening is very important. |
|
Skin |
Skin cancer |
Long-term skin cancer screening is very important. Protect your skin from the sun by using sunscreen and minimising exposure. |
|
Neck |
Thyroid cancer |
Discuss the risks with your doctor and have your thyroid checked on a regular basis. |