Doctor writing down a mesothelioma treatment plan.

What causes mesothelioma cancer?  There is currently only one known cause for a person developing mesothelioma and that is exposure to asbestos. Asbestos is made up of tiny fibers and when they get knocked around or disturbed, these micro-fibers go airborne where they can “sit” for hours if there is a lot of movement in the room.

Once the tiny asbestos fibers and/or dust enters the body via esophageal or tracheal intake, they will most likely become lodged in the chest or abdomen lining and because the body cannot expel these fibers, over time this lodging will disrupt natural cell development.  This uncontrollable growth of abnormal cells will ultimately lead to either asbestosis or some form of mesothelioma cancer.

Asbestos has been used in a variety of products such as textiles, insulation, and piping. It is a naturally occurring mineral that mankind mined for nearly a century. Its use peaked in the U.S. during World War ll but continued to be used until the mid-1980’s.  Over the years, people have been exposed to asbestos in several ways and now, the effects can be felt on an international level.

How Does Asbestos Cause Mesothelioma?

Cause of Pleural Mesothelioma

When a person inhales asbestos, the long thin fibers pass through the path of the respiratory system where they get trapped in the pleura, the lining of the lung. After being trapped, the needle like fibers cause chronic inflammation, irritation, and genetic damage to the pleura. The resulting cancerous cells multiply fast and uncontrollably and form tumors that wrap around the lungs. This causes fluid buildup in the lungs which in turn makes it difficult to breathe and causes severe pain. The right lung is often more affected than the left lung and more asbestos seems to settle in the lower part of the lungs than the upper part. Currently, researchers are not entirely sure about the process but they do have several theories:

Cellular inflammation – Cells are repeatedly damaged and become chronically inflamed and begin to rapidly multiply.

Genetic mutations – It is possible that asbestos causes genetic changes that lead to cancer.

Free radical-induced damage – Asbestos may trigger free radical production inside the body and increase the toxicity of the asbestos fibers while at the same time causing further damage to the mesothelial cells.

Asbestos fibers can also become trapped in the lining of the heart (pericardium) or the lining of the abdominal cavity (peritoneum). The process of becoming mesothelioma is the same regardless of which part of the body is affected.

Pleural Mesothelioma

Cause of Peritoneal Mesothelioma

Peritoneal mesothelioma is the second-most common type of mesothelioma. The peritoneum membrane surrounds the abdomen. It has two layers and the mesothelioma can develop in either or both. The parietal layer surrounds the abdominal cavity and the visceral layer surrounds the stomach and other abdominal organs. These layers together support the abdominal cavity and the organs inside of it.

Cancer experts associate the cause of peritoneal mesothelioma with the following theories:

  • When asbestos fibers are swallowed the fibers travel from the digestive system to the peritoneum.
  • When asbestos fibers are inhaled, they reach the peritoneum through the lymphatic system. The lymphatic system stores and produces the cells that help fight disease.

The body cannot digest asbestos and as the fibers begin to multiply a tumor is formed in the lining of the abdominal cavity. As it expands fluid begins to build up causing abdominal pain and loss of appetite.

Cause of Pericardial Mesothelioma

Pericardial mesothelioma is the rarest type of mesothelioma. Tumors first begin to form in the pericardium, the lining of the heart. Pericardial has the worst prognosis and is often not diagnosed until an autopsy has been performed.

In a small number of cases mesothelioma will begin in or between the two layers of the heart. When the cancer forms between the two layers of the mesothelium, the tissues begin to thicken. This reduces the ability of the heart to move freely. Fluid then begins to build (pericardial effusion) and at some point, tumors begin to grow and prevent the correct beating of the heart.

The exact process of how the asbestos reaches the pericardium and thus causes cancer is not known.

Final Thoughts On How Mesothelioma Is Caused

The process of asbestos leading to mesothelioma usually takes several decades. Although symptoms often appear in the early stages of the disease, they are often misdiagnosed. This misdiagnosis accounts for the poor prognosis of the disease as it is usually not discovered until it reaches the later stages. Once the cancer has reached an advanced stage it has usually begun to metastasize and has spread to nearby organs and the lymph nodes.

Show Sources

Resources:

  1. Dodson, R. and Hammar, S. Asbestos: Risk Assessment, Epidemiology, and Health Effects. Taylor & Francis: Boca Raton. 2006.
  2. National Institutes of Health. (2012, June 5). Mesothelioma – malignant. Accessed from http://www.nlm.nih.gov/medlineplus/ency/article/000115.htm
  3. Munkholm-Larsen, S., Cao, C. Q., & Yan, T. D. (2009). Malignant pleural mesothelioma. Accessed from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2999110/?tool=pubmed
  4. Stahel, R.A., Weder, W., Lievens, Y., & Felip, E. (2010). Malignant pleural mesothelioma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Accessed from http://annonc.oxfordjournals.org/content/21/suppl_5/v126.long
  5. National Comprehensive Cancer Network. (2012). National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology: Malignant pleural mesothelioma. Version 2.2012.
  6. Chua TC, Yan TD, Morris DL. Surgical biology for the clinician: peritoneal mesothelioma: current understanding and management. Can J Surg. 2009;52(1):59-64.
  7. Dodson, R. and Hammar, S. (2006). Asbestos: Risk Assessment, Epidemiology, and Health Effects Heidelberg. Springer Press
  8. Malignant mesothelioma treatment (PDQ). National Cancer Institute. Accessed from http://www.cancer.gov/cancertopics/pdq/treatment/malignantmesothelioma/patient. Accessed on November 10, 2016
  9. Types of treatment for mesothelioma by type.. Cancer Research UK. Accessed from: http://www.cancerresearchuk.org/about-cancer/type/mesothelioma/about/mesothelioma-risks-and-causes

Last Modified: Mar 31, 2017 @ 4:40 pm

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