When it comes to different treatments for mesothelioma patients, there is no shortage of diversity, as options include chemotherapy, radiation, surgery, immune-based therapies, gene-based therapies, and more. Chemotherapy treatments cisplatin and pemetrexed are first line treatments, especially among those who do not quality for surgery. Radiation treatment is available, but is typically the path less chosen – early studies indicates a fatal toxicity, and risks outweigh the benefits. However, recent studies have shown an increase in the benefits of radiation therapy, when radiation beams directly target the cancerous tumors, and when combined with immunotherapy treatments.
Radiation treatment works by producing high-energy x-rays to the affected areas, thus causing damage to the DNA of the cancerous cells. Radiation is also sometimes used with surgery, to help kill any remaining cells that perhaps surgery could not.
Intensity Modulated Radiation Therapy (IMRT) uses radiation beams that are shaped like the tumor to more directly target the cancerous area, delivering high doses of radiation with precision, leaving the surrounding healthy tissue and cell unaffected. Scientists and researchers believe IMRT is more effective after surgery, specifically after a pleurectomy/decortication (P/D), because only the tumors are removed in the process. With two lungs still intact, IMRT is better equipped to administer these precise dosages with accuracy.
With technological improvements over the years, higher dosages of radiation are considered much safer and are routinely delivered. Evidence has shown that the higher dosages allow for a shorter treatment course and the radiation is immunogenic. This has led scientists to believe that hypofractionated radiation can be used alongside immunotherapy. As the radiation shrinks the tumor size, the tumor becomes dormant, but not eliminated completely. A healthy immune system will attack this dormant tumor until cell death occurs, but in most cases of mesothelioma, the immune system has been compromised. Immunotherapy treatments attempt to restore the body’s own natural defense, so it can better fight off infections without the use of harmful chemicals and drugs.
Researchers and scientists believe that adding an immune check point blockade in combination with hypofractionated radiation may balance the immune system in a way that it can attack the dormant tumor. To test this, scientists administered immune check point blockades to a short course of radiation in mice models. Results showed a delay in tumor growth and the development of more T-cells. Immune-genes were regulated and cytokine production increased.
There is currently no cure for mesothelioma, and this rare and aggressive cancer does not respond well to many treatment options. Patients suffering from mesothelioma will receive certain treatments based upon their diagnoses, and how their body will react. Advances in technology have scientists and researchers hopeful that finding the right combination of therapy and treatment is in the near future.
Licun Wu and Marc de Parrot, “Radio-immunotherapy and chemo-immunotherapy as novel treatment paradigm in malignant pleural mesothelioma,” Translational Lung Cancer Research (June 2017) [Link]