The information on this page was reviewed and approved by
Maurie Markman, MD, President, Medicine & Science at CTCA.

This page was updated on September 21, 2021.

About mesothelioma

Mesothelioma is a rare cancer that develops in the lining of the body’s internal organs, called the mesothelium. Up to 80 percent of mesotheliomas begin in the lining of the lungs and are called pleural mesothelioma. Other forms of the disease are found in tissues surrounding the abdomen, in the lining of the heart and in the lining of the testicles.

According to the American Society of Clinical Oncology, around 3,000 cases of mesothelioma are diagnosed each year.

What causes mesothelioma?

The exact cause of mesothelioma is not known, but there are several factors that may increase the risk of developing the disease.

Exposure to asbestos fibers is a major risk factor for mesothelioma. Asbestos is a naturally occurring fibrous mineral that was found to have many useful industrial applications. It’s now known that asbestos exposure is harmful and linked to several types of cancer, most commonly mesothelioma.

Here are some key facts about common risk factors for mesothelioma:

  • Smoking by itself is not a risk factor, but smoking in combination with asbestos exposure may increase a person’s risk of developing the disease.
  • Asbestos exposure poses a long-term risk, as it may take more than 20 years from the last exposure before cancer develops.
  • SV40 (simian virus 40) infected some polio vaccinations between 1955 and 1963, and research is ongoing to determine whether a connection to mesothelioma exists, since the peak age range for those diagnosed with mesothelioma (ages 50 to 70) overlaps with the timing of exposure to SV40.
  • Until the 1950s, thorium dioxide used to be injected into the chest or abdomen before taking X-rays. Experts now believe there may be a link between thorium dioxide, followed by a high dose of radiation, and mesothelioma.

Learn about risk factors for mesothelioma

Who gets mesothelioma?

Men develop mesothelioma more often than women do, and the risk for the disease increases with age. The most critical risk factor is exposure to asbestos.

Today, the risk of exposure for workers in the manufacturing industry is much less because asbestos, by and large, is no longer used in the United States. Although the use of asbestos has decreased dramatically since the late 1980s, asbestos may still be found in older buildings and products.

Mesothelioma types

The types of mesothelioma are named for the cavities in which mesothelioma cancer cells develop. The types are:

  • Pleural mesothelioma, the most common type, which forms in the outer linings of the pleura (lungs) and internal chest wall
  • Peritoneal mesothelioma, which forms in the lining of the abdominal cavity (peritoneum)
  • Pericardial mesothelioma, which forms in the space surrounding the heart (pericardium)
  • Testicular mesothelioma, which forms in the lining that surrounds the testicles

Mesothelioma tumors can contain epithelioid cells or sarcomatoid cells, or they can be biphasic (containing both epithelioid and sarcomatoid cells). The sarcomatoid mesothelioma cell type is the most resistant to treatment.

Learn more about the types of mesothelioma

Symptoms of mesothelioma

The symptoms associated with malignant pleural mesothelioma tumors may be similar to lung cancer and other conditions affecting the lungs or chest. Pleural effusion, a complication of the disease, is the buildup of fluid in the chest. It may cause difficulty breathing.

Other common signs of pleural mesothelioma include:

  • Pain
  • Chest pain
  • A dry (sometimes painful) cough
  • Shortness of breath
  • Difficulty swallowing
  • Weakness and/or fatigue
  • Back pain
  • Unexplained weight loss

Common symptoms of peritoneal mesothelioma include:

  • Abdominal pain
  • Accumulation of fluid in the abdomen (swelling)
  • Diarrhea, constipation or other changes in bowel habits
  • Unexplained weight loss

Pericardial and testicular mesotheliomas are very rare. Pericardial mesothelioma symptoms may be similar to those for other heart conditions, such as heart palpitations or irregular heartbeat, difficulty breathing, murmurs, night sweats and chest pain. One known symptom of testicular mesothelioma is hydrocele, which is a buildup of fluid in the scrotum.

Learn more about symptoms of mesothelioma

Diagnosing mesothelioma

Evaluations performed for a mesothelioma diagnosis may include:

  • Blood tests
  • Thoracoscopy, which is used to examine the inside of the chest and may include a biopsy
  • Mediastinoscopy, which is used to examine the space between the lung and may include a biopsy
  • Bronchoscopy, used to examine and biopsy tissue samples in the lungs, bronchi and trachea
  • Laparoscopy, which is used to look inside the abdomen and may include a biopsy
  • Computed tomography scan (CT scan)
  • Magnetic resonance imaging (MRI)
  • Positron emission tomography (PET)/CT scan

Learn about diagnostic procedures for mesothelioma

Mesothelioma treatments

According to the American Cancer Society, the five-year survival rate for malignant pleural mesothelioma ranges from 8 percent for cancer that has spread to distant parts of the body to 20 percent for cancer that has not spread beyond the pleura. Mesothelioma is often a hard type of cancer to treat because it usually spreads along surfaces instead of growing as a single tumor mass like many other cancers.

Treatment options for mesothelioma include:

  • Chemotherapy, including hyperthermic intraperitoneal chemotherapy (HIPEC)
  • Immunotherapy
  • Radiation therapy
  • Extrapleural pneumonectomy, a surgery to remove a lung and portions of other organs
  • Pleurectomy/decortication, a surgery to remove the pleural lining of the chest wall, the pleural lining of an affected lung, the mediastinum and the diaphragm
  • Debulking, a surgery to remove as much of the cancer as possible
  • Omentectomy, a surgery to remove a layer of fatty tissue (omentum) that covers the organs in the abdomen
  • Targeted therapy

The stage, tumor location and cell type all contribute to a patient’s mesothelioma prognosis and life expectancy. For mesothelioma cancer that has not been discovered at an early stage, and has spread to other organs or lymph nodes, oncologists at our cancer centers may recommend a care plan that focuses on palliative treatments.

Learn about treatment options for mesothelioma