Radiation therapy is one of the most common cancer treatments, including for mesothelioma. During the treatment, patients will have a radiation beamed directly at the cancerous cells. The radiation molecularly destroys the cells and prevents them from replicating. It is noninvasive which is a major advantage of this type of cancer treatment.
How Radiation Treatment is Administered
There are two main methods for administering radiation treatment for mesothelioma. The first type is called external beam radiation and can include 3D Radiation Treatment (also called 3D conformal radiotherapy) and Intensity Modulated Radiation Therapy. During treatment, a machine emits radiation beams towards the infected area of the patient. The machine will rotate around the area being treated, but it will never come in contact with the body. The treatment is completely non invasive and is usually done as an outpatient procedure.
The 3D Radiation Therapy is called conformal radiotherapy because metal blocks placed in the radiation beam path force the beam to change shape. The goal is to administer a high dose of radiation directly to the cancer cells. The ‘3D’ comes from the fact that the beam must be conformed based on width, depth and height. This type of radiation is effective when tumors are close to organs that radiation could harm.
The Intensity Modulated Radiation Therapy (IMRT) relies on collimators to direct an intense shaped beam towards the tumor. During treatment the collimators move so the radiation beam can be targeted on a specific spot. It allows effective radiation dose distribution while limiting radiation exposure to healthy tissue surrounding the tumor.1
The second type of radiation treatment for mesothelioma is Brachytherapy, or internal radiation treatment. The treatment involves a small radioactive device being surgically implanted near the location of the tumor. Then, highly concentrated radiation beams are aimed directly at the tumor. The benefit of this method of radiation treatment is that it affects fewer non-cancerous cells.
Radiation therapy is often given repeatedly, such as five times per week for a set period of time. The schedule of radiation therapy will vary on a per-person basis depending on factors such as the patient’s disease progress and the response to treatment.
Advantages and Disadvantages of Radiation Treatment
The main benefit of radiation treatment for mesothelioma is that it is usually targeted specifically at the tumor. Thus, fewer healthy cells are affected by the treatment and side effects can be minimized. However, radiation treatment cannot always be precisely targeted. This is why radiation treatment is rarely used for peritoneal mesothelioma; there is too much risk that the beams could affect abdominal organs which are particularly sensitive to radiation.
Most cases of mesothelioma are not caught until their later stages when they have metastasized. During these stages, radiation therapy may not be an effective option. Even in the earlier stages of mesothelioma, radiation therapy is not very effective as a sole treatment. More commonly it is used in conjunction with surgery and/or chemotherapy. In combination therapy, radiation treatment has shown to significantly improve prognosis of pleural mesothelioma patients. However, the patients that may benefit the most will exhibit certain characteristics before treatment including early stage mesothelioma and good physiological status.2
Side Effects of Radiation Treatment
The side effects of radiation treatment vary depending on where the radiation is delivered. Many people experience very mild side effects and especially if the radiation treatments only last a few weeks. Also, radiation treatment is typically given in conjunction with other treatments which can have their own side effects similar to radiation. It can be difficult separating the source of symptoms. Patients should talk to their doctors about what to expect from radiation treatment for mesothelioma. These are the most common side effects associated with the treatment:
- Fatigue
- Diarrhea
- Nausea
- Low libido
- Inflammation
- Difficulties swallowing
- Changes to urination
- Skin redness
The types of side effects you experience depend on the location of the treatment. For example, if you are upper chest is the target of radiation therapy you may develop a sore throat.3 Some side effects of radiation treatment can be long-lasting, such as liver damage, inflamed lung tissues, cardiac damage, or inflammation to the spinal cord.
Radiation therapy is used because it can destroy cancer cells. It is most effective though when used with other therapies. If you have mesothelioma, your doctor will probably recommend radiation therapy as just one component of a multi-therapy regimen.
References
1 David C. Rice MB, Craig W. Stevens MD, PhD, Arlene M. Correa PhD, Ara A. Vaporciyan MD, Anne Tsao MD, Kenneth M. Forster PhD, Garrett L. Walsh MD, Stephen G. Swisher MD, Wayne L. Hofstetter MD, Reza J. Mehran MD, MS, Jack A. Roth MD, Zhongxing Liao MD, W. Roy Smythe MD. (Nov 2007) Outcomes After Extrapleural Pneumonectomy and Intensity-Modulated Radiation Therapy for Malignant Pleural Mesothelioma, The Annals of Thoracic Surgery, v84:5, 1685-1693.
2 Bagheri R, Haghi SZ, Rahim MB, Attaran D, Toosi MS. Malignant pleural mesothelioma: clinicopathologic and survival characteristic in a consecutive series of 40 patients. Ann Thorac Cardiovasc Surg, v17:2, 130-136.
3 Radiotherapy for mesothelioma (Nov 2010) Retrieved from Cancer Research UK – CancerHelpUK at: http://cancerhelp.cancerresearchuk.org/type/mesothelioma/treatment/radiotherapy-for-mesothelioma
