Mesothelioma radiation therapy uses high-energy X-rays or protons to kill cancer cells. Mesothelioma can be difficult to treat with radiation therapy because the cancer does not grow as single tumors. It can be challenging to focus the radiation on the tumors without affecting healthy tissue. But newer radiation therapy techniques are providing better control of the radiation beams and are making this treatment more useful for mesothelioma. (Cancer.org)

Radiation Use Cases

Radiation therapy may be used in the following ways to treat mesothelioma:

Adjuvant mesothelioma radiation therapy

After surgery to kill remaining cancer cells that could not be seen during surgery. With any mesothelioma surgery, there is a chance of tumors to come back. Radiation can be used to prevent the cancer from recurring. (Mesothelioma.com)

Palliative radiation therapy

This treatment reduces the painful symptoms of mesothelioma, such as chest pain and difficulty breathing, bleeding, and trouble swallowing. Radiation for palliative reasons is often used with stage 3 or 4 patients when cancer has spread.

Surgery for Mesothelioma After Radiation Therapy (SMART)

This is a new form of radiation treatment that is used before surgery. The patient receives a high dose of radiation therapy, usually much higher than normal. Surgery is done about a week later to remove cancerous tissue. Clinical studies suggest this can help keep the cancer in one area for removal.

This may help to extend life, especially for patients with pleural mesothelioma. In one clinical trial, using the SMART method combined with an extrapleural pneumonectomy was able to extend the life of stage 3 and 4 cancer patients to four years and longer.

Types of Mesothelioma Radiation Therapy

There are two major forms of radiation therapy for mesothelioma. There are benefits and risks for both types. Mesothelioma patients should speak to their doctor about which is best for them.

External Beam Radiation Therapy (EBRT)

EBRT for mesothelioma uses high-power radiation beams to attack malignant tumors. A computer guides the radiation beams, which avoids health tissues and organs while targeting tumors to kill cancer cells.

A specific kind of EBRT that is often used on mesothelioma is intensity-modulated radiation therapy (IMRT). It allows your radiologist to adjust the power of the radiation beams according to the size of the tumor, location, and other factors.

Also, IMRT is 3-D radiation therapy. It uses a computer-controlled machine that moves around the cancer patient and creates radiation beams that conform to the shape of the tumor. This process allows for intense radiation beams to target tumors with as little damage as possible to healthy tissue.

A recent clinical study showed that IMRT followed by an extrapleural pneumonectomy could boost life expectancy among some patients to 39 months. Typically, only about 35% of pleural mesothelioma patients live beyond one year from diagnosis.

Brachytherapy

This type of radiation therapy is less common for mesothelioma. But clinical trials continue to study the possibility that this form of radiation therapy can help patients. This radiation type is different from EBRT; high doses of radiation are applied directly to the tumor. Because the treatment is targeted inside the body more than EBRT, it has fewer effects on healthy tissues.

The two types of brachytherapy are:

• Permanent: The radioactive seeds are never taken out of the body. But they usually cease emitting radiation after three to 12 months, depending on the dose and the type of material used.
• Temporary: Radioactive seeds are implanted for a set period of time, such as a few weeks or months. The length of time depends on the goals of the radiation therapy.

Mesothelioma Radiation Therapy Side Effects

All cancer treatments have side effects, and mesothelioma radiation therapy is no exception. It is vital to discuss all possible side effects of your cancer treatment with your doctor. Report any that occurs during your treatment process. There are several radioprotective drugs and other palliative treatments that can be given to you to reduce side effects.

Common side effects of mesothelioma radiation therapy are:

• Fatigue: Most patients have a loss of energy and extreme fatigue after receiving radiation therapy. This problem can last for months after treatment is completed.
• Hair loss: Some patients may have a loss of body hair where the radiation is applied.
• Mouth problems: Inflammation of the oral cavity, dry mouth, and lack of taste are possible side effects.
• Skin problems: Redness, dryness, darkening, and peeling of the skin is common after radiation treatment, which can imitate sun exposure symptoms.

There can be other side effects based on where the radiation is being applied. If you have peritoneal mesothelioma, you could have nausea, vomiting, loss of appetite, and diarrhea after having radiation to the abdomen.

To fight side effects of radiation treatment, patients should get a lot of rest, eat a healthy diet, and review all medications and supplements they are taking with their doctor.

Radiation Therapy Clinical Study

A 2014-2018 clinical trial at the National Cancer Institute of Aviano, Italy, involved 108 mesothelioma patients found that patients were twice as likely to live two years or longer if they were treated with radiation therapy. (Sciencedaily.com)

The study involved patients whose pleural mesothelioma tumors could not be entirely removed with surgery. All patients were given surgery followed by chemotherapy.

Of the patients who received aggressive radiation therapy of 50 Gy to the left or right side of the trump, followed by 60 Gy to the exact location of the tumor, 58% were still living after two years. In the patients who received less aggressive, palliative radiation therapy of 20-30 Gy to the tumor site,  only 28% were still alive after two years.

Study leader Marco Trovo, MD, stated that the research showed a ‘clear survival benefit’ in using this type of radiation therapy for mesothelioma patients whose tumors cannot be entirely removed by surgery.

Summary

Radiation treatment is becoming more common in mesothelioma patients, in combination with surgery and/or chemotherapy. Talk to your doctor to determine if radiation therapy could be an option for you with your mesothelioma.