Radiation therapy for those suffering from mesothelioma is not typically the first line of treatment because of its overall effectiveness. High-energy x-rays, gamma rays, and neutrons that make up radiation treatment aim to shrink tumors and ultimately kill cancer cells, but since mesothelioma tumors often have an irregular shape, it can be difficult to target with radiation therapy.
Damage to nearby healthy cells during radiation has always been a major concern when considering this treatment. Radiation generally has less severe side effects than chemotherapy, but side effects still do occur, and often. Fatigue, hair loss, nausea, trouble swallowing, and changes to the skin can be some of the side effects that can take a toll on an already weakened mesothelioma patient.
Effective radiation treatment hinges on the oxygen levels that lie within the tumors. Increased oxygen levels allow radiation to produce free radicals, which are unstable molecules that can build up and damage proteins, lipids, and even DNA. However, free radicals (also known as oxidants) when stimulated correctly, can induce apoptosis, or cell death – ultimately killing cancer cells.
Researchers from the University of Ohio have recently found that a drug typically used to treat various types of muscle spasms, may improve oxygen levels within mesothelioma tumors, rendering radiation treatments more effective. This treatment, papaverine, was discovered in the mid-1800s and is derived from the opium poppy. Since its FDA approval, Papaverine today is generally used to smooth and relax muscles, but it was once used a pain reliever after surgery when combined with morphine and codeine (called papaveretum). Papaverine can also increase blood supply in major organs.
Scientists hypothesized that that with just a single dose of papaverine before radiation therapy, oxygen levels in the mesothelioma tumors should increase, rendering radiation treatment more effective with a standard dose. Theoretically, if the radiation treatment is more effective upon these oxygenated tumors, then perhaps less radiation treatment is needed to kill the cancer cells. This will mean fewer side effects for the patient, as healthy cells are less likely to be affected. Continued research on the subject has scientists and researchers hopeful their theory can be tested in the coming months.
Source:
Martin Benej, et. al. “Papaverine and its derivatives radiosensitize solid tumors by inhibiting mitochondrial metabolism,” Proceedings of the National Academy of Sciences and the United States of America (September 10, 2018). [Link]
McGill University, “Free radicals: What doesn’t kill you may make you live longer,” Science Daily (May 8, 2014). [Link]
“Antioxidants and Cancer Prevention was originally published by the National Cancer Institute.” [Link]
