Along with surgery and chemotherapy, radiation therapy is one of the three most commonly used treatments for mesothelioma. For information on the other types of treatment, please see “Mesothelioma Treatment Options.”
Radiation: The Basics
Radiation therapy uses ionizing radiation to kill or slow down the growth of cancer cells. Radiation therapy can be used as a stand-alone treatment, or in conjunction with other treatments such as mesothelioma chemotherapy or surgery. The exact treatment regime a given patient receives depends on the type of cancer, stage of development, and overall general health.
Radiation therapy can be used both as a curative treatment and as a palliative treatment. When used for curative reasons it is commonly administered following surgery that removes the bulk of tumors. In this case the radiation is given to kill any remaining cancer cells not removed during surgery.
In the case of palliative treatment, the cancer is usually too far advanced for surgery to be an effective treatment option. Radiation therapy is given to provide relief from pain by shrinking tumors slightly.
In terms of mesothelioma, radiation therapy is often palliative because mesothelioma cancer is aggressive and highly resistant to treatment. In addition, mesothelioma is often diagnosed too late for curative surgery to be possible. For these reasons, it is very rare for any type of mesothelioma treatment to be effective in the long term. Mesothelioma has an almost 100 percent mortality rate.
There are three main types of radiation therapy: external beam radiotherapy, unsealed source radiation therapy, and brachytherapy. Generally only external beam radiotherapy and brachytherapy are used to treat mesothelioma, while unsealed source radiotherapy is used for other reasons. The type of radiation treatment patients receive depends on several factors, including the type of mesothelioma they have, the stage the disease is at, and whether they have any other treatment options.
External Beam Radiotherapy
External Beam Radiotherapy is the most commonly used type of radiation therapy for the treatment of cancer, and for mesothelioma. During this procedure, the patient sits or lies down in a position that exposes the treatment area, and a beam of radiation is directed at the treatment area.
A patient will usually receive several treatments. The net result is that the radiation kills cancer cells and limits the rate at which new cancer cells can grow and spread. However, it is not typically feasible for all tumor cells to be killed. External beam radiotherapy is usually a palliative treatment carried out to relieve pain, or is carried out in conjunction with surgery or chemotherapy.
Also known as “sealed source radiation therapy,” brachytherapy involves the implantation of tiny radioactive rods in or near tumors. In addition to mesothelioma, this type of radiation therapy is used to treat breast, cervical, and prostate cancer.
The radioactive “seeds” used in brachytherapy are tiny rod-shaped objects that emit radiation in a radius of approximately one centimeter. This very short distance means that the radioactive seeds can deliver concentrated doses of radiation that can be targeted to tumors much more accurately than other types of radiation therapy. In the case of mesothelioma this is an important advantage, because the increased accuracy and penetration is useful in treating a disease that is highly resistant to treatment.
Another important advantage of this type of radiotherapy is that the concentrated and specific dose means healthy tissue is largely unaffected. A radioactive seed can be implanted in a tumor, and then emits radiation in only a one centimeter range, so the healthy tissue surrounding the tumor receives very little radiation and the patient also benefits from side effects that are much less severe. Overall, the patient is in much better health following this type of radiation therapy, and experiences fewer complications or side effects.
People with mesothelioma may receive temporary or permanent treatment, in which radioactive seeds are placed in the patient for a short time and then removed, or are placed and then left in the tumor permanently. In the latter case the seeds emit radiation for only a limited period of time, usually for three to twelve months.
Unsealed Source Radiation Therapy
This type of treatment involves giving a patient a soluble dose of a radioactive substance. It is administered orally or via an injection for the treatment of a limited number of cancers. This treatment is used rarely because people who receive unsealed source radiation actually become radioactive, and can pose a health risk to other people, particularly children and pregnant women. However, unsealed source radiation is not a treatment for mesothelioma.