Radiotherapy uses x-rays and electrons to treat skin tumors. The mycosis fungoides variant of cutaneous T cell lymphoma (CTCL) was one of the first cancers to be treated with radiation therapy just a few years after X-rays were discovered in the late 1800s.
Radiation therapy can be used to treat individual CTCL lesions or the entire surface of the skin.
What is electron beam radiation?
Electron beam radiation is a type of radiotherapy consisting of very small electrically charged particles generated in a linear accelerator and directed towards the skin.
Electron beam radiation therapy has replaced orthovoltage (low energy) X-ray therapy in many centers treating cutaneous T-cell lymphoma.
Advantages of electron beam radiation over conventional X-rays
Orthovoltage (low energy) X-rays can effectively treat recurrent cutaneous lymphoma lesions, but their penetration into the underlying tissues (blood vessels, muscles, bone marrow) is a disadvantage if the disease is extended. In contrast, electron beam therapy delivers radiation primarily to the surface layers of the skin.
Electron beam radiation is very damaging to the tumor cells but is fairly well tolerated by the normal cells of the surrounding skin.
How is electron beam radiation delivered?
Electron beam radiation can be located or applied to the entire surface of the skin.
Localized electron beam therapy
- The electron beam is directed at localized areas of cutaneous lymphoma.
- Typically, 10-15 treatments are given eliminating approximately 90% from mycosis fungoides (MF) plates.
- Localized electron beam therapy is used for localized disease in addition to nitrogen mustard ointment, phototherapy or chemotherapy.
Total electron beam therapy on the skin
- Total Skin Electron Beam Therapy (TSEB) directs radiation to the entire skin surface of the body and is used for large areas of cutaneous lymphoma.
- Treatment with TSEB is commonly performed by the person receiving therapy standing in front of the radiation machine and in a series of positions designed to expose all areas of the body to the radiation beam.
- Alternatively, the patient can stand on a slowly rotating platform in front of the electron beam.
- A standard approach is to deliver a total of 3,600 cGy in small fractions three times a week for approximately 10 weeks.
- During the course of treatment, measurements are made of the amount of radiation reaching different parts of the body. Some areas of the body, such as the hands and feet, are prone to receiving too much radiation and may need to be protected during parts of the treatment. Also, it is often necessary to “augment” small areas of the skin with additional treatments if these areas have not received enough radiation.
There is no sensation or discomfort with the electron beam treatment. Most people can tolerate treatments with minimal or moderate side effects well.
How does electron beam radiation work?
- The electron beams kill tumor cells by damaging their DNA.
- Electron beams can cause breaks in DNA that impede cell function and proliferation.
- Tumor cells are more sensitive to damage from electron beam radiation due to their rapid cell turnover.
- Radiation therapy aims to maximize the destruction of Cancer cells while minimizing damage to nearby normal cells.
Side Effects of Electron Beam Radiation for Cutaneous Lymphoma
- During or shortly after therapy, electron beam radiation can cause acute effects, such as fatigue, itching, tanning, and burns (such as sunburn).
- Although these acute side effects are occasionally severe, they are self-limiting if appropriate supportive therapy is administered in a timely manner.
- Long-term effects include dry skin, decreased sweating, changes in skin color, scalp loss. hairand the development of dilated blood vessels (telangiectasia)
- Electron beam radiation can also increase a person's risk of developing skin cancer.
- The psychological impact resulting from altered physical appearance (hair loss) due to TSEB can be substantial.