Say the word “radiation” around pleural mesothelioma experts, and you’ll likely get a split in opinions. Some believe in the treatment’s benefit, while others feel the therapy has too many toxic side effects for patients.
A recent medical advancement could lead to a resurgence in using radiation.
Toward the end of the 20th century, lung-sparing surgery emerged as an option for pleural mesothelioma patients. However, keeping both lungs resulted in complications when patients underwent traditional radiation therapy (also called radiotherapy) following the surgery. For this reason, many specialists moved away from using radiation as a postoperative treatment.
The inception of intensity-modulated radiation therapy (IMRT) may prevent some of the common health issues — and put radiation back at the forefront of mesothelioma treatment.
A multimodal treatment plan is the best strategy for treating pleural mesothelioma. Multimodal treatment involves using numerous types of care, usually surgery combined with either chemotherapy or radiation (or both).
If you’re recently diagnosed with pleural mesothelioma, you should look into finding a doctor who will utilize a multimodal treatment plan. The top oncologists consider all types of treatment and will combine different forms of care to maximize your chances of survival.
We at Mesothelioma Guide can help you find a trustworthy and esteemed mesothelioma specialist. Please email our patient advocate and registered nurse, Karen Ritter, at email@example.com for more information about pleural mesothelioma treatment.
How Do You Treat Pleural Mesothelioma?
The first part of multimodal pleural mesothelioma treatment is often surgery. There are two primary pleural mesothelioma surgeries: extrapleural pneumonectomy (EPP) and pleurectomy with decortication (P/D).
EPP is the original pleural mesothelioma surgery. It involves removing the thin lining between the lung cavity and chest wall, which is called the pleura and where pleural mesothelioma forms. It also removes part of the diaphragm and the affected lung.
However, not all patients should have one of their lungs removed. Some patients, especially elderly ones, cannot survive for long with only one lung.
Taking out the lung sometimes isn’t even necessary. If the disease is detected early enough, then the tumors might not have spread yet to the lung.
This is why P/D emerged as an alternative option. This surgery removes the pleura and affected part of the diaphragm — and other affected tissue — but doesn’t include taking out the lung. It’s easy to understand how P/D is less risky than EPP for many pleural mesothelioma patients.
Dr. Kenneth Rosenzweig, a mesothelioma specialist at Mount Sinai Medical Center in New York City, said many mesothelioma doctors prefer P/D rather than EPP. He reported in an article published in the Annals of Translational Medicine that P/D can “decrease operative toxicity” for patients.
But how does postoperative treatment change with both lungs still intact after P/D surgery? Dr. Rosenzweig brought up this exact topic in his report.
“As the use of P/D has increased in popularity over EPP,” Dr. Rosenzweig wrote, “it became important to develop techniques to treat the pleura and chest wall with the remaining lung in the treatment field.”
A problem can arise when using radiation following P/D surgery.
Radiation and Pleural Mesothelioma Surgery
Mesothelioma is a cancer that multiplies and spreads at a rapid pace in the body. However, damage to the cells’ genes prevents this duplication. Mesothelioma specialists use radiation therapy (also called radiotherapy) to target the diseased cells, which can die if damaged enough.
Doctors often use radiation therapy as an “adjuvant” treatment, meaning it follows the primary form of care (surgery). Mesothelioma consists of microscopic tumors, and the disease is difficult to remove altogether during surgery.
Even if removed in bulk when the pleura, diaphragm and other tissue are removed, remnant tumors often remain inside the patient. Radiation can attack these residual tumors and “control” the disease, which means it doesn’t spread once again.
The energy particles are dangerous to all cells, though — even healthy ones. The tissue on the lungs, in particular, is at a high risk. Since the cancer forms near the lung cavity, the radiation energy is sent toward this general area and can harm healthy lung tissue.
Following their P/D surgery, many pleural mesothelioma patients experience “pneumonitis” due to undergoing radiation therapy. This issue refers to inflammation of lung tissue.
“When we were doing more EPP, you didn’t have to worry about pneumonitis because you take the lung out,” said Dr. Raja Flores, a mesothelioma surgeon at Mount Sinai Medical Center.
In his research, Dr. Rosenzweig noticed significant rates of pneumonitis for patients who underwent traditional radiation following P/D surgery. Some patients had fatal toxicity.
IMRT seems to solve this issue.
What Is IMRT?
IMRT is an advanced, refined type of radiation. It uses the same practice as traditional radiation: sending energy waves into the body and targeting diseased cells.
The difference is IMRT is more targeted. Radiation specialists can focus the energy beam on just the location where the tumors exist — and reduce damage to healthy cells. Since the radiation is more concentrated toward the tumors, oncologists can utilize a lower dose.
“The bottom line of radiation therapy, you want radiation to hit the cancer cells while sparing normal cells,” Dr. Flores said. “(IMRT) is a technique we feel does help to do that. It’s not 100% but there is nothing 100%.”
In theory, IMRT spares the lung and targets only the remaining mesothelioma cells not removed during surgery.
“I think you hit the nail on the head by saying ‘in theory,’” Dr. Flores said. “In practice, I’m not sure how much of a difference it is.
“It depends on how they do the technique and the experience of the radiation oncologist. … As long as the radiation oncologist is focused on preserving the underlying structures, then that’s what’s most important.”
Finding an experienced radiation oncologist is essential to reducing the damage to healthy tissue. The easiest way to find this quality of care is through our free Doctor Match program.
How Does IMRT Help Pleural Mesothelioma Patients?
IMRT helps pleural mesothelioma patients by allowing them to undergo lung-sparing surgery and receive radiotherapy after their operation. This multimodal treatment removes the bulk of the tumors and controls the remaining disease, which can extend patients’ lives.
“IMRT, with its ability to deliver concave doses of (radiotherapy) … is a logical solution,” Dr. Rosenzweig wrote. “Recent studies in the use of IMRT show that the safety has improved with experience and has excellent (results).”
Dr. Rosenzweig cited a study that found a median survival of two years for patients who underwent P/D followed by IMRT. Less than 10% of the patients experienced Grade 3 or worse pneumonitis. That’s a much better rate than the 28% rate of Grade 3 or Grade 4 for traditional radiation.
Another study — one published just last month — focused on the benefits of radiation for pleural mesothelioma. Specifically, the article published by the American Society for Radiation Oncology connected using IMRT after P/D surgery.
Researchers found only a few patients who experienced pneumonitis. Incidence of “grade 3 pneumonitis” ranged from 0% to 16%, depending on the study. Grade 4 and 5 pneumonitis occurred in fewer than 1.5% of cases.
The median progression-free survival time for patients was between 12 and 16 months, and median overall survival was between 19 and 28 months. The researchers called these outcomes “reasonable” and defended the use of IMRT following P/D surgery.
The experts concluded by asking for “exercising careful attention to dose constraints” to prevent overexposure of healthy tissue to the radiation waves.
“IMRT can thus be considered in well-selected patients in whom adequate survival following (P/D) is expected,” the report finished.
Sources & Author
- How Radiation Therapy Is Used to Treat Cancer. American Cancer Society. Retrieved from:
https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/radiation/basics.html. Accessed: 02/28/2020.
- Disease-Related Outcomes and Toxicities of Intensity-Modulated Radiation Therapy Following Lung-Sparing Pleurectomy for Malignant Pleural Mesothelioma: A Systematic Review. American Society for Radiation Oncology. Retrieved from: https://www.ncbi.nlm.nih.gov/pubmed/32088429. Accessed: 02/28/2020.
- Malignant pleural mesothelioma: adjuvant therapy with radiation therapy. Annals of Translational Medicine. Retrieved from:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5497112/. Accessed: 02/28/2020.
- Intensity-Modulated Radiation Therapy (IMRT). Radiologyinfo.org. Retrieved from: https://www.radiologyinfo.org/en/info.cfm?pg=imrt. Accessed: 02/28/2020.
Sources & Author