Mesothelioma is an aggressive type of cancer that affects the “mesothelium”, a thin membrane that covers and protects certain body organs. Mesothelioma is caused by exposure to asbestos and usually affects the lining of the lung cavity but may affect other parts of the body including the abdomen, heart and chest wall.
Mesothelioma is a fairly rare cancer with about 3,000 new cases diagnosed annually. Most of these are related to occupational exposure but even though asbestos use has dropped dramatically in the U.S., the cancer can take 20 to 50 years to develop and new cases continue to emerge.
With occupational exposure, individuals who worked in industries that used asbestos as insulation are most vulnerable. Anyone who worked with asbestos while removing it, installing it or as it was used for insulation may be at risk. This mainly includes shipbuilders, steel workers, military veterans, automotive industry workers and construction workers but can involve others as well.
Family members of those who worked with asbestos may also be at risk as the worker may have carried the fibers and dust home on clothing or belongings. This dust containing asbestos could have been inhaled or ingested by anyone in the home, known as secondary exposure. In most cases, the longer the exposure to asbestos, the greater the risk. In some cases however, short term exposure, particularly if severe or extensive may be enough to induce the development of mesothelioma.
Asbestos and Mesothelioma
Over 70 percent of those who develop mesothelioma were exposed to asbestos at work. Asbestos is a thin, fiber-like material which may be present as “dust” with microscopic asbestos fibers. These fibers can be inhaled and lodge in the lungs, ingested to lodge in the abdomen or may enter the bloodstream in some cases. Once lodged in the body, the fibers cause inflammation, scarring and genetic damage which may result in cell mutations and the development of cancer. Tumors often develop on top of scar tissue and are known as “plaques” which are cancerous.
Asbestos exposure typically occurs decades before cancer is developed and diagnosed. The delay between exposure and diagnosis is known as the “latency period”. Such a long latency period, makes diagnosis of the disease more difficult.
Over an extended time, these fibers collect and agitate the pleural region, causing cellular damage and the development of scar tissue. This causes otherwise healthy cells to become abnormal and replicate constantly, which leads to the growth of tumors.
Types of Mesothelioma
Asbestos exposure may result in several types of mesothelioma which are identified by the area of the body in which cancer develops.
Pleural Mesothelioma – Asbestos-related cancer of the pleural lining surrounding the lungs. Pleural mesothelioma accounts for 75 percent of all mesothelioma cancers and is caused by inhalation of asbestos fibers which lodge into the linings of the lungs. Prognosis will depend on the stage of disease and patient characteristics.
Peritoneal Mesothelioma – Asbestos-related cancer of the peritoneal lining inside of the abdominal cavity. It accounts for about 20 percent of all mesothelioma cancers and is caused by ingestion of asbestos fibers. Prognosis will depend on the stage of disease and patient characteristics.
Pericardial Mesothelioma – Asbestos-related cancer of the pericardium which is a mesothelial layer surrounding the heart. Pericardial mesothelioma is fairly rare, occurring in only about 5 percent of mesothelioma cancer cases. This type of mesothelioma is most commonly not diagnosed while the patient is living.
Testicular Mesothelioma – Asbestos-related cancer of the mesothelial layer surrounding the testicles. It is the rarest type of mesothelioma, occurring in less than 1 percent of all cases. Testicular mesothelioma is often difficult to diagnosis but may have a better prognosis than most other types.
Symptoms of Mesothelioma
Mesothelioma may have different symptoms that depend mainly on the location of the cancer. In general however, patients may experience:
Irregular Heart Beat
Shortness of Breath
Persistent cough, Chest, abdominal or testicular pain
Gastrointestinal disturbance
Fluid retention in abdomen, chest, lungs or testicular area. Weight Loss.
Diagnosing Mesothelioma
Mesothelioma often takes 20 to 50 years to develop and symptoms may appear suddenly. Most patients experience a cough or symptoms similar to pneumonia due to pleural mesothelioma but symptoms for other types of mesothelioma may vary. When symptoms are persistent without an obvious cause, imaging studies may be recommended first.
Depending on the location, imaging studies may include X-ray, CT scan, and / or PET scan. Based on imaging study results, specific blood tests may be ordered to detect certain proteins which may be present in blood. If these proteins are present, a surgical biopsy may be performed in the affected area. Tissue removed in a biopsy will be examined under a microscope by a pathologist to confirm cancer cell development and type.
Different cellular layers of the mesothelium may develop cancer cells. These include cells which are identified as epithelioid, sarcomatoid or biphasic. The determination of type of cancer cells, where and how large any tumor development is, will help the physician determine treatment options.
Staging of Mesothelioma Cancer
The location of mesothelioma and type of cancer cells will help determine treatment options but the “stage” of cancer will have a great influence. The stage of cancer also identifies how advanced the cancer has become, what the patient prognosis may be and may determine how likely it is that treatment will be successful.
There are multiple types of staging systems to classify mesothelioma. The most common is the IMIG system which is used for pleural mesothelioma but it and other types of mesothelioma may be staged using other classification systems as well.
Cancer development may be classified into:
Stage 1 – Tumor is localized and there are no cancer cells in surrounding lymph nodes. Mesothelioma is rarely diagnosed at this early stage due to the latency of disease and likelihood that initial symptoms will be overlooked or confused with other disease states.
Stage 2 – Mesothelioma tumor(s) have not spread beyond local area but some lymph nodes contain cancer cells. Disease states caught at this stage are treatable by a number of options including surgery, chemotherapy and radiation.
Stage 3 – Mesothelioma has spread beyond the initial area and more lymph nodes are affected with greater numbers of cancer cells present in greater numbers of lymph nodes. Aggressive surgery combined with other treatment may still be possible.
Stage 4 – Mesothelioma has spread to distant parts of the body and tumors may have developed on other organs including the liver, kidney, brain and others. This is the most advanced stage with the poorest prognosis including the possibility of organ failure and treatment options may be limited.
Mesothelioma prognosis
The “prognosis” describes the likelihood of survival. This is a difficult issue for both physicians and patients to address and may be described in percentages for a number of years survival rates such as a 75 percent, 5 year survival rate.
Prognosis is determined by:
- Type of mesothelioma
- Tumor cell type
- Size and location of tumor(s)
- Stage of mesothelioma
- General health of patient
- Gender and other patient characteristics
- Blood characteristics
Based on the stage of the patient’s disease and prognosis, different treatment options will be discussed to attempt to remove the cancer and extend the lifespan or if severe, to provide relief of pain and discomfort. As different staging systems are used, it is essential that a patient diagnosed with mesothelioma see a physician who is a specialist in the disease and are also advised to seek a second opinion.
Mesothelioma Treatment Costs
As a clear link has been shown between mesothelioma and asbestos exposure, several lawsuits have been successful at holding specific companies and industries responsible for the costs of mesothelioma treatment and losses caused by the disease.
Several patients who filed mesothelioma lawsuits have been awarded judgements in the $millions including amounts of $337 million, $30.3 million and $22 million for three individuals and their families. Each lawsuit is different, there is no guarantee of award and cases must be evaluated independently but there may be as much as $30 billion remaining in an asbestos relief fund, paid for by responsible companies, to provide for patient treatments.
