Radiation therapy
Radiation therapy involves the use of x-rays to kill tumor cells, but it also affects healthy cells nearby. It can be given externally, or by placing radioactive substances within the pleural space. External radiation therapy used alone does not extend survival in malignant mesothelioma, although it may cause the tumor to shrink. Effective doses in malignant mesothelioma would require very large doses of radiation to a wide area of the body -- with associated damage to nearby structures, including the lungs and esophagus.

Lower doses of radiation therapy (external or internal) have been used in combination with surgical treatments (especially pleurectomy) to prevent local tumor recurrence. Low doses have also been used to prevent tumor spread along wound tracts left from invasive diagnostic procedures. For patients with inoperable disease, lower dose radiation therapy may be helpful in reducing the size of the tumor and to provide pain relief.