How Radiation Treats Mesothelioma
Radiation therapy for mesothelioma uses beams of radiation, like X-rays, to target cancer cells and damage their DNA. When cancer cell DNA is severely damaged, the cells die and can no longer replicate, helping to prevent metastasis, or cancer growth. It can take days or weeks for the cells to die, and they continue to die for weeks or months after the radiation treatment.
Adjuvant Mesothelioma Radiation Therapy
Adjuvant treatment refers to secondary treatment. Adjuvant radiation therapy is performed after surgery in an attempt to kill remaining cancer cells and prevent recurrence. With surgical resection, there is a potential for mesothelioma tumors to recur, which could potentially be prevented with the use of radiation.
Surgery for Mesothelioma After Radiation Therapy (SMART)
Surgery for Mesothelioma After Radiation Therapy (SMART) is a new type of radiation used prior to surgery. A high dose of radiation therapy is administered, typically at a much higher dose than normal. Surgery is then performed about six days later to remove the affected tissue. Studies suggest that this can help confine the cancer to one area for surgical resection, which has shown success in extending life expectancies, especially for malignant pleural mesothelioma patients. In one study, the SMART method combined with an extrapleural pneumonectomy (EPP) was able to extend life expectancies for stage 3 and stage 4 epithelioid mesothelioma patients to longer than four years.
Palliative Radiation Therapy
Palliative treatment can be given to mesothelioma patients at any stage and time during their treatment journey to help reduce symptoms and improve quality of life. Radiation for palliative purposes is typically used with stage 3 or stage 4 mesothelioma patients, when their cancer has spread, to help shrink tumors and reduce symptoms like pain, difficulty breathing and shortness of breath caused by pressure on the lungs and abdominal organs.
Types of Mesothelioma Radiation Therapy
There are two main types of radiation therapy treatments for mesothelioma, including external beam radiation (EBRT) and brachytherapy, which is also referred to as internal beam radiation therapy (IBRT). Benefits and risks are different for each type, and patients should discuss options with their medical team.
External Beam Radiation Therapy (EBRT)
External beam radiation therapy for mesothelioma is a non-invasive procedure that uses intense radiation beams to target malignant tumors. A computer is used to guide the beams, avoiding healthy organs and tissues while targeting malignant tumors to damage and kill cancer cells.
A specific type of EBRT that is common for mesothelioma treatment is intensity-modulated radiation therapy (IMRT), which allows the radiologist to adjust the strength of radiation beams according to tumor size, location and other factors. IMRT is also a three-dimensional radiation therapy, using a computerized machine that moves around the patient and creates radiation beams that conform to the tumor shape, allowing for intense beams to target malignant tissues with minimal damage to healthy cells.
A recent study has shown IMRT followed by an extrapleural pneumonectomy could extend patient life expectancies to as long as 39 months. In comparison, typically only around 35% of pleural mesothelioma patients have a survival rate of longer than a year.
External Beam Radiation Therapy Procedure
- Patients lie flat on a table and parts of the body are covered to protect from radiation.
- A technician is located in another room to control the radiation machine and communicate to the patient through an intercom.
- The radiation machine begins administration, which is typically pain-free and quick for the patient.
- Radiation is typically done several times per week, but depends on patient characteristics and other in-progress treatments.
Brachytherapy is less common for the treatment of mesothelioma, but clinical trials continue to research the potential for IBRT to help improve patient prognosis. This treatment is different from EBRT in that high doses of radiation are applied directly to the tumor. Since the treatment is more targeted inside the body, it has minimal effect on nearby, healthy tissues.
There are two types of brachytherapy, including:
- Permanent brachytherapy: Radioactive seeds are never removed, though they usually stop emitting radiation after a period of 3 – 12 months, depending on the dosage and type of radioactive material used in the treatment.
- Temporary brachytherapy: Radioactive seeds are implanted for a predesignated period of time, such as several weeks or months, before removal. The length of time depends on the goals of the radiation and the dosage.
- Using a metal tube or catheter, radioactive seeds or rods are inserted near the tumor.
- Highly concentrated doses of radiation are administered directly to the tumor.
- For temporary therapies, the applicator may be left in place for seed removal.
- The procedure typically can be done as an outpatient procedure, without hospital requirements.
- Despite low levels of radiation emissions after the procedure, patients should avoid interaction with pregnant women and small children as they are prone to the effects of radiation.
Resources for Mesothelioma Patients
Radiation Therapy Side Effects
All cancer treatments have side effects, including mesothelioma radiation therapy. Patients should discuss all potential side effects with their physician, and report any that arise during the treatment process. There are radioprotective medications or other palliative treatments that can be applied simultaneously to reduce the severity of treatment side effects.
Common Side Effects of Radiation Therapy
- Fatigue: Many patients report loss of energy and extreme fatigue following radiation treatments, which can also last for months after treatment has concluded.
- Hair loss: Patients may experience bodily hair loss at the area of radiation application.
- Mouth problems: Dry mouth, inflammation of the oral cavity and lack of taste have all been reported as common radiotherapy symptoms.
- Skin problems: Redness, dryness, peeling and darkening of the skin is common after radiation, mimicking symptoms of sun exposure.
Other side effects may emerge based on where radiation therapy is being applied. For peritoneal mesothelioma patients, nausea, vomiting, diarrhea and loss of appetite are also common after administration to the abdomen. To combat side effects, patients should get plenty of rest, maintain a balanced and healthy diet, as well as discuss all supplements and medications that they are taking with their mesothelioma specialist. It’s also important for patients to take care of their skin with special attention to any soaps, lotions, cosmetics and perfumes being used.