Mesothelioma radiation therapy is a treatment option that can be used alone or in conjunction with another treatment such as surgery or chemotherapy. A physician or team of physicians can help you determine your best treatment options. Radiation affects cancer cells – indeed, all cells – by breaking the DNA molecules contained in them. Cancer cells in particular cannot easily repair broken DNA chains, so effective radiation treatment kills the cells or slows their reproductive rate.
Radiation Administered Externally or Internally
In a radiation treatment, high-energy x-rays, photons, neutrons, or cobalt is administered to kill cancer cells or shrink a tumor. The radiation can be delivered from an external source — a machine that directs a beam of radiation at a target in the patient's body — or internally through a needle, thin tube, or wire that is placed in or near the targeted site. Another mesothelioma radiation therapy option is the use of radioisotopes, which circulate radiation throughout the body. External application of the treatment affects the healthy tissue surrounding a tumor, which is one of the drawbacks of traditional radiotherapy. Some techniques have been developed to target this form of therapy more precisely.
Intensity Modulated Radiation Therapy
IMRT was introduced with the advent of Computerized Tomography (CT) scans which can provide a 3D image of a tumor within the body. An IMRT machine delivers radiation to the tumor from several exterior angles, using varying intensities of radiation. The result is a much more precise form of external treatment for a tumor, causing less harm to healthy tissues. The treatment can also be brief and be repeated more frequently than regular treatment because dosages are lower. The patient is able to tolerate more treatment and the precision makes the treatment more effective. This approach is also used in proton therapy, allowing for a more accurate depth setting for the radiation.
Ongoing Radiation Treatments
A series of radiation treatments is usually necessary to be effective. Even so, mesothelioma radiation therapy is usually not enough to completely eliminate the cancer. That's why mesothelioma radiation therapy is usually an adjuvant therapy – which means treatment that follows surgery. In the case of mesothelioma it is nearly always used in conjunction with a chemotherapy regimen. Radiation is also used to reduce the possibility of "seeding" malignant cells that may be caused by surgical resection of the tumor. Mesothelioma cases are rarely diagnosed early enough that surgery can remove all the malignant cells, and the disease has an unfortunate tendency to recur – presumably because asbestos fibers are still present.
Radiation may also be used as a palliative treatment, meaning treatment designed to relieve discomfort in the patient with an advanced stage of the disease. Patients who are beyond therapy to reduce the tumors caused by mesothelioma may experience some pain relief by reduction of the chest mass using radiation. Palliative therapy using radiation may also reduce pleural effusion, the accumulation of fluid in the chest that can cause respiratory problems4.
Side Effects of Radiation Therapy for Mesothelioma
Mesothelioma radiation therapy can help reduce the shortness of breath and pain that mesothelioma patients experience. However, because healthy cells are also damaged by the radiation that kills the cancer cells, mesothelioma radiation therapy is often followed by side effects such as:
- Difficulty swallowing
- Body aches and stiffness
- Skin irritations
- Hair loss
- Digestive problems
Side effects become more prominent as treatment goes on, and diminish to the point of insignificant within two months after the completion of treatment. The point at which they begin depends on dosage and frequency. Radiotherapy side effects may also be exacerbated by chemotherapy that is being applied concurrently.
Typical Mesothelioma Radiotherapy Program
The schedule used for a patient's mesothelioma radiation therapy depends on the type of mesothelioma the patient has, the stage of the cancer and its location, and the strength of the patient. Radiation treatment can be as frequent as daily or as infrequent as weekly depending on medical circumstances. All of these protocols will continue for six weeks or more for aggressive treatment programs. Some patients need to have fluid drained from the chest or abdomen as a part of palliative radiation treatment.
- Radiation Therapy Principles, American Cancer Society, http://www.cancer.org/Treatment/TreatmentsandSideEffects/TreatmentTypes/Radiation/RadiationTherapyPrinciples/radiation-therapy-principles-how-does-radiation-work
- New Radiation Therapy Technology, University of Maryland Medical Center, http://www.umm.edu/news/releases/rapidarc.htm
- Prevention of Malignant Seeding…with Pleural Mesothelioma, Chest, Boutin et al, June 1995, http://chestjournal.chestpubs.org/content/108/3/754.full.pdf
- The Role of Palliative Radiotherapy in Malignant Mesothelioma, PubMed, National Institutes of Health, http://www.ncbi.nlm.nih.gov/pubmed/1720658
- Radiation Therapy Side Effects, National Cancer Institute, http://www.cancer.gov/cancertopics/radiation-therapy-and-you/page6