Differences Between Mesothelioma and Asbestosis

Mesothelioma and asbestosis are two lung diseases caused by asbestos exposure. Mesothelioma is a rare but aggressive cancer. Asbestosis causes inflammation and scarring in the lungs, but is not cancer. Mesothelioma can take decades to develop, while asbestosis can develop in a matter of years. If you have been exposed to asbestos, it is important to see a doctor for regular checkups.

Facts About Mesothelioma

  • Mesothelioma is a cancer that develops in mesothelial tissue throughout the body.
  • Cellular types can be epithelioid, sarcomatoid or a combination, called biphasic.
  • The average life expectancy for mesothelioma is 12 to 21 months.
  • More than 3,000 cases are diagnosed annually in the United States.

Facts About Asbestosis

  • Asbestosis is not cancer and is limited to the lungs and respiratory tract.
  • Scar tissue formation can progress to respiratory distress.
  • Asbestosis is incurable; however, patients can survive for several decades with treatment.

Malignant mesothelioma is a type of cancer, and asbestosis is a form of pulmonary fibrosis. Mesothelioma is cancerous because of DNA damage and the formation of tumors as a result of unrestricted cellular growth.

Pulmonary fibrosis, such as asbestosis, is not cancer and is instead characterized by scar tissue within the lungs that restricts breathing through tissue thickening and stiffness.

Mesothelioma vs asbestosis diagram

Scar tissue resulting from asbestosis is irreversible and causes increasing respiratory distress over time. However, tumors do not form, and asbestosis is limited to the lungs and respiratory tract.

Conversely, mesothelioma is a cancer of the mesothelium, a type of tissue that lines the outside of the lungs, chest cavity and abdomen. Mesothelioma tumors can develop in any of these locations.

In malignant pleural mesothelioma, tumors form in the pleural tissue lining the outside of the lungs and have the potential to damage other structures in the chest such as the heart or diaphragm.

Prognosis and life expectancy also differ between asbestosis and mesothelioma. Mesothelioma cancer treatment is challenging, and only 23% of patients survive for three or more years. Asbestosis is a chronic respiratory condition and, although also incurable, treatment can prolong survival for several decades.

Similarities of Mesothelioma and Asbestosis

Even if asbestosis isn’t a cancerous condition, it shares many of the same symptoms as mesothelioma, including shortness of breath. Inflammation resulting from asbestos exposure causes both diseases.

Mesothelioma and asbestosis share many overlapping symptoms, including:

  • Shortness of breath
  • Chest tightness and pain
  • Persistent dry cough
  • Loss of weight and appetite
  • General fatigue and weakness
Common symptoms of asbestosis and mesothelioma

Mesothelioma patients typically experience these symptoms more severely earlier in their disease than asbestosis patients. Asbestosis patients may not have severe symptoms until many years after diagnosis.

Both diseases can also cause a condition called pleural effusion. As swelling and inflammation increase over time, cellular waste and fluid accumulate in the pleura surrounding the lungs. The increased pressure on the lungs exacerbates most symptoms and can lead to respiratory distress.

How Asbestos-Related Diseases Develop

Significant, prolonged or repeated exposures to asbestos fibers are the cause for all asbestos-related diseases. Asbestos fibers are small, needle-like mineral compounds that travel through the air when asbestos-containing materials are disturbed or break apart.

The body cannot degrade asbestos fibers after inhaling them, causing the mineral to become trapped within the lungs, pleura and other tissue. Their presence triggers the immune system to raise an inflammatory response in an attempt to remove the fibers.

Over time, the inflammation causes damage and scarring, leading to one or more asbestos-related diseases.

These diseases include:

  • Asbestosis
  • Mesothelioma
  • COPD
  • Lung cancer
  • Pleural thickening
  • Pleural effusion
  • Atelectasis
  • Pleural plaques

Malignant mesothelioma and asbestos-related lung cancer develop as a result of damage to DNA caused by repeated inflammation and the unique shape of asbestos fibers. Faulty DNA leads to unrestricted cellular division and the formation of cancerous tumors, which can grow and spread throughout the body.

Repeated inflammation in the lungs also leads to scar tissue formation and asbestosis. Scar tissue is more rigid than healthy tissue and causes the lungs to stiffen, restricting their ability to expand for a full breath.

Scar tissue that forms in the alveoli blocks oxygen from entering the bloodstream. Combined with increased lung rigidity, these issues cause chronic deficiencies in oxygen and respiratory complications that progress with age.

Diagnosing Mesothelioma and Asbestosis

Diagnosing any asbestos-related disease requires thorough medical and occupational screening. Similar to other forms of pulmonary fibrosis, the cause of asbestosis may not be revealed through a review of symptoms and simple imaging unless there is a known history or risk of toxic exposure.

The first step in diagnosing both diseases is talking with a primary care physician about respiratory changes or other health issues. A doctor will order a chest X-ray or CT scan to determine if there are visual abnormalities in the lungs, according to a 2021 review by the U.S. National Library of Medicine.

Unfortunately, neither illness has discrete imaging findings until the disease has progressed for several years.

Initial signs of either illness may appear on imaging as areas of higher density, which could represent either scar tissue or a small tumor mass. Because these signs take so long to develop, a diagnostic picture does not begin to form until many years after asbestos exposure.

To differentiate between asbestosis and mesothelioma, however, a biopsy must be performed.

There are several types of biopsies, including:

  • Bronchoscopy: A doctor inserts a small camera attached to a thin, flexible tube through the nose or mouth into the breathing passages to visualize tissue and retrieve a sample.
  • Needle Biopsy: Often used with guided imagery, a doctor uses a needle to remove liquid containing a sample of cells for pathological identification.
  • Thoracoscopic Surgery: Thoracoscopy is a more invasive approach that allows surgeons to remove a core sample of tissue and offers the best method of cell identification.

These procedures may also help physicians identify signs of pleural thickening or pleural effusion, which could lead to a diagnostic confirmation. In most cases, doctors do not rule out cancer until a biopsy is returned negative.

Dr. Jacques Fontaine and Dr. Virginia Wolf
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Mesothelioma Treatment vs. Asbestosis Treatment

Treatment options for mesothelioma include surgery and other cancer treatments, while asbestosis treatment is limited to surgery. Once a patient is confirmed to have mesothelioma, treatment will involve anti-cancer therapies based on the stage and cell type. Treatment will also depend on whether metastasis has occurred and if there is cancer present elsewhere in the body.

Surgery is the best option for patients with early-stage mesothelioma. Doctors often combine treatment for mesothelioma with other modalities, such as chemotherapy and radiation, to eradicate any remaining cells.

Unfortunately, because of the long latency period of the disease, mesothelioma is often not diagnosed until a later stage has developed.

Mesothelioma surgical options may include:

  • Extrapleural Pneumonectomy: EPP, the most aggressive surgical option, removes an entire lung, the lining around it, affected lymph nodes and parts of the diaphragm and heart sac.
  • Pleurectomy and Decortication: This surgery involves the removal of the lining around the lungs and all visible tumors. Surgeons then scrape the surface of the cancerous lung to remove the remaining cancer cells.
  • Pneumonectomy: An alternative to EPP, this surgery removes only the affected lung. While considered a less aggressive option, recent data points to better survival in some patients.

Asbestosis treatment options for most patients are limited to surgical procedures that promote breathing by draining excess fluid from the chest cavity and lungs. Rarely, in severe cases, advanced asbestosis patients may be eligible for a lung transplant, an option not available for asbestos cancer.

Both asbestosis and mesothelioma patients may be prescribed pain medication to reduce breathing discomfort. Asbestosis patients are also likely to receive breathing treatments with bronchodilators.

Asbestosis progression worsens with age, and patients can expect more frequent treatment, such as supplemental oxygen and antibiotics, to control symptoms and prevent infection.