About Mesothelioma

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Mesothelioma is a rare form of cancer that mainly arises in the mesothelial lining of the lungs, heart or abdomen. These three main types of mesothelioma are called pleural mesothelioma (lung), pericardial mesothelioma (heart), and peritoneal mesothelioma (abdomen).  Research continues every day to determine types of mesothelioma affecting other parts of the body.


Pleural Mesothelioma

Pleural mesothelioma is the most common type of mesothelioma, a rare cancer that develops in the mesothelium (a membrane that lines many of the body’s organs and cavities). In the case of pleural mesothelioma, the cancer develops in the lining of the lungs, called the pleura or pleural membrane. Although a mesothelioma prognosis is typically poor for the majority of patients, some who are diagnosed early may qualify for a combination of aggressive therapies to improve life expectancy.


Peritoneal Mesothelioma

Of the 2,000 to 3,000 cases of mesothelioma diagnosed in the United States annually, 10 to 20 percent of the patients are diagnosed with peritoneal mesothelioma. Peritoneal mesothelioma develops in the abdomen, in the mesothelial cells that form a layer called the peritoneum.


Pericardial Mesothelioma

Pericardial mesothelioma accounts for approximately half of all pericardial tumors and is an extremely rare. Researchers from various mesothelioma studies report that pericardial mesothelioma accounts for approximately 1 to 6 percent of all mesotheliomas. To date, fewer than 150 cases have been presented in medical literature and approximately 200 cases have been reported worldwide. Pericardial tumors are typically spread out and tend to cover most of the heart.


Latency Period


The term latency period is used to describe the period of time between exposure to a potential disease-causing agent and the time the disease becomes apparent. According to most experts, in the case of mesothelioma the latency period ranges from 20 to 50 years after initial exposure to asbestos occurred, though there have been instances when the time period is shorter or longer. Generally a patient will not demonstrate symptoms of mesothelioma until 20 to 50 years after initial exposure to asbestos.

Due to the long latency period associated with the cancer, those exposed to asbestos during the 1950s, ’60s and ’70s are beginning to demonstrate mesothelioma symptoms today, decades after they were exposed to asbestos.




  • Patients typically experience a latency period of 25 to 50 years after initial exposure before symptoms arise. Less than 1 percent of patients have a latency period shorter than 15 years.
  • Around 14 to 30 people out of every million will be affected by mesothelioma each year.
  • The National Institute of Health (NIH) estimates that 11 million people were exposed to asbestos between 1940 and 1978.
  • Approximately 50 percent of patients will experience a life span of 8 to 18 months after treatment. About 30 percent or more have a chance of living five years or longer
  • More than 2,000 new cases of mesothelioma are diagnosed each year.
  • The disease is commonly diagnosed in people between the ages of 50 and 70 years.
  • Males are four times more likely to be diagnosed with mesothelioma than females.
  • Three-fourths of cases develop in the pleura. About 10 to 20 percent form in the abdomen.





Mesothelioma develops when asbestos fibers are inhaled or ingested into the body. Once in the body, the fibers can become lodged in organs or cavities, causing inflammation or infection and cellular damage. Overtime, cancerous cells begin to divide uncontrollably, causing the membranes in the affected location to thicken. Fluid begins to build up in the spaces between membrane layers and tumors begin to form, causing impaired bodily function



Doctors use staging systems in order to diagnose potential treatment options for patients. Depending on the nature of the cancer, different surgery and chemotherapy options may be available. An internationally accepted staging system allows doctors to explore potential treatment procedures that are more beneficial to the patient.

Because of the need for an internationally accepted staging system, three systems for diagnosing malignant mesothelioma were developed. The majority of doctors tend to use the TNM system. While these staging systems are used primarily for pleural mesothelioma, there is currently no formal staging system for the other types of this cancer.


TNM Staging System

The TNM system was developed by the International Mesothelioma Interest Group (IMIG) as the International Mesothelioma Staging System. The different parts of the diagnosis include:

(T) signifies the size of the tumor and location of the tumor.

(N) describes whether or not lymph nodes have been affected.

(M) determines whether the tumors have metastasized into other parts of the body.


Several different factors determine the stage of the tumor:

Tumor Classification



The tumor is limited to the ipsilateral parietal pleura as well as the mediastinal and diaphragmatic pleura. However, there is no involvement of the visceral pleura.


The tumor has involved the ipsilateral parietal pleura along with the mediastinal and diaphragmatic pleura.


The ipsilateral pleural surfaces, which include the parietal, mediastinal, diaphragmatic and visceral pleura, have been invaded by the tumors.


The tumor has expanded locally, but is potentially resectable. It has invaded all of the ipsilateral pleural surfaces, which include the parietal, mediastinal, diaphragmatic and visceral pleura.


The tumor is locally advanced and is unresectable. It has involved all of the ipsilateral pleural surfaces including the parietal, mediastinal, diaphragmatic and visceral pleura.





Symptoms of mesothelioma often resemble other illnesses such as influenza and pneumonia, which can make diagnosis difficult. Patients with pleural mesothelioma may experience persistent raspy cough, difficulty breathing and swallowing, night sweats, fatigue and chest pain. Symptoms of peritoneal mesothelioma include diarrhea or constipation, nausea, fever, swelling or pain in the abdomen and anemia. Pericardial mesothelioma patients may experience chest pain, heart palpitations, difficulty breathing, fever and fatigue.