What is mesothelioma

There's also benign (noncancerous) tumors of the mesothelium, and these are also called mesothelioma.
Symptoms and diagnosis

Malignant mesothelioma is a cancer of the mesothelium. The mesothelium is a layer of tissue that surrounds plenty of of the body's organs. The mesothelium serves as a buffer between a quantity of the body's moving parts (the beating heart) and more rigid parts (breastbone).

Mesothelioma can have vague symptoms shared with plenty of other, less serious conditions, so a doctor will try to rule out those conditions through a physical exam, which could include x-rays and tests of lung function. Imaging tests such as MRIs, CAT scans and PET scans may be completed.

Symptoms differ depending on where the mesothelioma occurs in the body. Pleural (lung) mesothelioma, the most common type of mesothelioma, may cause symptoms such as breathing problems and chest pain.

Pleural mesothelioma is the most common type (75 percent of diagnoses) of malignant mesothelioma. This is a cancer of the mesothelial tissue surrounding the lungs and lining the chest wall.

The only way to definitively diagnose mesothelioma is through analysis of tissue taken from the mesothelium through biopsy. The biopsy can be completed by inserting a camera and surgical instruments through a small incision (thoracoscopy in the chest or laparoscopy in the abdomen) or by opening up the abdominal or chest cavity (thoracotomy or laparotomy). The tissue sample will be examined through a microscope to detect patterns that differentiate it from benign cells or other types of cancerous cells. If diagnosis is still unclear, tests for different chemicals in the cells or genetic testing of the cells may be needed, or an electron microscope can offer a closer look at the cells.
Types of mesothelioma

Pericardial mesothelioma is rare; it affects the mesothelial tissue surrounding the heart.

Peritoneal mesothelioma is the second-most common (10 percent-20 percent). It affects the mesothelial tissue surrounding the abdominal organs.

Mesotheliomas of the tunica vaginalis testis (in men) and tunica serosa uteri (in women) are rare. These cancers affect the mesothelial tissue surrounding the male or female internal reproductive organs.
Stages of disease

Only pleural mesothelioma has a formal staging system. Staging is mainly used to give a prognosis and help select a work of treatment.

Stage I: Localized, has not spread.

The main staging system, used by the American Joint Committee on Cancer, uses a TNM system to choose a stage: T for tumor, (size and extent of spread); N for nodes (extent of spread to lymph nodes); and M for metastasis (extent of spread to far-away organs). Each pleural mesothelioma case will be given a ranking, from low (less severe) to high (more severe); T1 through T4, N0 through N3, and M0 through M1. Based on the combined TNM rankings, a stage will be assigned:

Stage II: Advanced mesothelioma, involving neighboring structures such as diaphragm or lungs. No spread to lymph nodes or metastastis.

Stage III: Advanced mesothelioma, involving neighboring structures as well as lymph nodes. No metastasis.

Stage IV: Advanced mesothelioma that has metastasized.
Treatment

Surgery, chemotherapy and radiation are standard for all types of malignant mesothelioma. Treatment is often focused on reducing symptoms (palliative therapy) and giving the patient more time to live, than getting rid of the cancer and going in to remission (curative therapy). This is because mortality is high despite treatment; it is often not caught until at an advanced stage; the cancerous cells are often spread out; and because patients are often weak for extensive treatment.

Surgery is used as a palliative and/or curative therapy. It is the only curative therapy, usually used in Stage I (has not spread) in a healthy patient. Used to remove the cancer and possibly nearby tissue or a lung. May also be used palliatively for procedures such as draining accumulated fluid that is causing discomfort.

Chemotherapy is used as a palliative therapy. It can be taken intravenously or intramuscularly, by mouth as a pill or locally injected in to affected area.

Combination therapy is the use of surgery, chemotherapy and radiation. It is the most effective, but the most difficult; and in most cases the cancer will still return at some point.
Diagnosis rates and survival rates

Radiation is also palliative. It is also used after surgery to avoid spreading mesothelioma to the incision site.


Risk factors

Mesothelioma is relatively rare. About 2,000 to 3,000 people are diagnosed in the U.S. each year, but these rates seem to go down. The average life expectancy after diagnosis is six year. The 5-year relative survival rate for mesothelioma is about 10 percent, but new treatments offered today may improve survival rates for those recently diagnosed

Other theorized risk factors include exposure to simian virus 40 through elderly polio vaccines, radioactive thorium dioxide and the asbestos-like mineral zeolite

The biggest risk factor by far for developing mesothelioma is exposure to asbestos particles, often at work. Asbestos exposure occurred in 70 percent-80 percent of people with mesothelioma. Diagnosis usually occurs 20 to 50 years after exposure, and even low levels of exposure can be carcinogenic to some. Relatives members of exposed people have higher rates of occurrence as well, due to particles brought in to the home from work. Mesothelioma is more common in men, people over 65 and white people.