Malignant pleural mesothelioma (MPM) is a thoracic malignancy and the most common form of mesothelioma. Patients may come in to see a doctor with chest pain and breathlessness related to a pleural effusion, which is a pathologic collection of fluid between the visceral and parietal pleura in the thoracic cavity.
Testing
There are a variety of imaging tests that can be done to attempt to detect mesothelioma. A chest radiography usually shows a pleural effusion or a pleural mass. A thoracic ultrasound can also be done in order to estimate the size of an effusion. A CT scan can also be helpful when diagnosing MPM. However, 35 to 46 percent of patients who have pleural malignancy have a benign CT report. A negative PET-CT scan may not tell the full story, so there should be more investigations to see if there are no signs of mesothelioma from this scan. A PET-CT scan can be done to locate the best area for histological sampling.
PET-CT is usually used to stage MPM, because its diagnostic accuracy is high. It can identify extra-thoracic metastases. An MRI will show a more precise guess at pleural tumor volume.
Subtypes
There are subtypes of mesothelioma which include epithelioid, sarcomatoid and biphasic mesothelioma. It is important to identify these subtypes as they have a direct correlation to prognosis. Epithelioid mesotheliomas look like carcinomas from a morphological sense and usually are accompanied with pleural effusions, while sarcomatoid mesotheliomas look like sarcomas and are accompanied with pleural masses. It can be hard to determine the subtype of mesothelioma that a patient has. Identifying molecular-based biomarkers can be more informative and allow for better, more specialized treatment.
It is thought that MPM patients may benefit from oncolytic viral therapy, which uses modified viruses to infect and destroy tumor cells and is used to fight many cancers.
Immune checkpoint inhibitors have been tested for the treatment of MPM. CTLA-4 is an immune suppressive receptor that inhibits T-cell responses. Anti-CTLA-4 was given to mice with mesothelioma; it affected tumor growth and increased overall survival. Another immune checkpoint is PD-1 /PD-L1 PD-1. Anti-PD-L1 or PD-1 agents have been studied.
Processes
There are different processes that may take place in the body because of asbestos exposure. Asbestos fibers may penetrate mesothelial cells and disrupt mitotic spindles causing chromosomal abnormalities. Also, the death of mesothelial cells due to asbestos leads to release of high mobility group box 1, which then leads to chronic inflammation. Additionally, macrophages try to digest asbestos fibers, but they are not able to, resulting in the production of reactive oxygen species, which causes intracellular DNA damage and abnormal repair. Additionally, when someone inhales asbestos fibers it causes irritation, leading to tissue damage. These are just a sampling of the multitude of disruptive processes that can take place within the body due to asbestos exposure.
First line therapy for mesothelioma tends to be chemotherapy which emerged from a study by Vogelzang. Based on a randomized study of 456 mesothelioma patients being treated with a combination of pemetrexed and cisplatin, there was an improved survival rate from 9.3 months to 12.1 months.
If you or a loved one has been diagnosed with an asbestos-related disease, please call (800) 505-6000 for legal help. For more information, fill out the form on our Homepage.
Sources:
https://www.sciencedirect.com/science/article/pii/S0954611117304006
https://journals.sagepub.com/doi/pdf/10.1177/1758835920971421
