Mesothelioma is a cancer that occurs in the mesothelium. Mesothelium is a thin protective layer of tissue that covers the majority of the internal organs. Mesothelioma is an aggressive form of cancer which is difficult to treat. This form of cancer is further divided into:
- Pleural Mesothelioma: This type of cancer happens to the tissue that surrounds the lungs (pleura) and is the most common form of mesothelioma. Three out of every four cases of mesothelioma disease begin in the pleural mesothelium
- Other rarer forms of mesothelioma are peritoneal mesothelioma – which affect the tissue of the abdomen. Mesothelioma can also occur in the surrounding tissues of the heart and testicles.
Regardless of their origin, malignant cells from the mesothelium can invade and damage nearby tissues, they can also metastasize, or spread, to other parts of the body. Mesothelioma is often diagnosed when the disease is in the advanced stage. The five-year survival rate is around 5% to 10%.
- Signs and symptoms of mesothelioma vary depending on where the cancer occurs. Pleural mesothelioma, which affects the tissue that surrounds the lungs, causes signs and symptoms that may include:
- Shortness of breath. Accumulation of fluid in the pleura caused by the mesothelioma, if sufficiently large, may also contribute to the shortness of breath
- Chest pain.
- Painful coughing
- Unusual lumps of tissue under the skin of the chest
- Unexplained weight loss.
Peritoneal mesothelioma, which occurs in tissue in the abdomen, causes signs and symptoms that may include:
- Abdominal swelling and pain
- Unexplained weight loss
Symptoms of other types of mesothelioma are unclear, since these forms of the disease are very rare. Pericardial mesothelioma, which affects tissue that surrounds the heart, has symptoms such as breathing difficulty and chest pains. Mesothelioma of tunica vaginalis, which affects tissue surrounding the testicles, may be first detected as swelling or a mass on a testicle.
The main risk factor for mesothelioma is exposure to asbestos. Asbestos is a group of minerals with thin microscopic fibers. These fibers are resistant to heat, fire, and chemicals and do not conduct electricity. Due to these properties, asbestos has been mined and used extensively in the construction, automotive, and other industries.
Asbestos fibers particulates are released into the air, when used in the manufacturing industries. They can then be easily inhaled or swallowed, leading to serious health problems. Approximately 75% of mesothelioma cases can be linked to exposure to asbestos. Other risk factors of mesothelioma are:
- Exposure to zeolites: These minerals are chemically related to asbestos and is believed to be a cause factor of mesothelioma.
- Radiation: There have been a few published reports of mesotheliomas that developed following exposure to high doses of radiation to the chest or abdomen.
- SV40 virus: Some studies in laboratory animals have raised the possibility that infection with the simian virus 40 (SV40) might increase the risk of developing mesothelioma.
If there are symptoms that might indicate mesothelioma, the doctor will conduct a physical exam to check for any lumps or other unusual signs. The doctor may order imaging scans, such as a chest X-ray or CT scan of your chest or abdomen, to look for abnormalities. Depending on the findings, further tests may be recommended to determine whether mesothelioma or another disease is causing the symptoms.
- Blood Tests: Blood levels of 3 substances – fibulib 3, osteopontin and soluble mesothelin related peptides (SMRPs) are often seen to be elevated in people suffering from mesothelioma.
- Fluid and Tissue Sample tests: Build-up of fluid in the body that may be related to mesothelioma, therefore the doctor can remove a sample of the fluid by inserting a needle through the skin into the area of fluid build-up. The fluid can then be examined under a microscope for cancer cells
- Biopsy: It is a procedure through which a small portion of the affected tissue is removed and sent for laboratory examination. It is the only way to accurately determine whether there is mesothelioma. Depending on the area of the body that is affected, the doctor selects the right biopsy procedure:
- Inserting a needle through the skin. The doctor might remove fluid or a piece of tissue with a thin needle inserted through the skin on your chest or abdomen.
- Collecting a sample of tissue during surgery. A fluid or tissue sample might be collected during an operation. The surgeon might make a small incision and insert a tube with a video camera to see inside your chest or abdomen. Special tools can be passed through the tube to collect a tissue sample.
Once the mesothelioma is confirmed, additional tests maybe recommended to understand whether the cancer has spread to the lymph nodes or to other areas of the body. The tests may include:
Basis the tests, the stage of the cancer can be determined and the optimal treatment can be planned.
Treatment for mesothelioma depends on a number of factors such as (but not limited to) stage of the cancer, size of the mesothelioma, whether it can be removed completely by surgery or not, fluid build-up in the chest and/or abdomen, age and general health, type of mesothelioma cells and whether it is a recurrence or not. Three standard types of treatment are used: surgery, radiation, and chemotherapy. Treating mesothelioma often involves a combination of two or all three
Surgery for malignant mesothelioma can be divided into two categories – those performed for the relief of symptoms and those performed with curative intent. Four main types of surgeries can be done to treat mesothelioma:
- Wide local excision: This removes the cancer along with some of the healthy surrounding tissue
- Pleurectomy and decortication: In this case a part of the pleura covering the lungs is removed along with a part of the chest lining, and outside surface of the lungs.
- Extrapleural pneumonectomy: This involves removing one whole lung and part of the lining of the chest, the diaphragm, and lining of the sac around the heart.
- Pleurodesis: This involves using chemical or drugs to make the lung lining scar and stick to the lung. The scarring stops the fluid build-up
In radiotherapy, high-energy X-rays and other types of radiation is used to kill mesothelioma cells or prevent them from growing. Radiation may be administered externally or internally. While external radiation therapy uses machines outside the body to send radiation toward the cancer, internal radiation uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into the area near the mesothelioma.
This is a cancer treatment that uses drugs to stop the growth of mesothelioma cells, either by killing the cells or by stopping them from dividing. Chemotherapy can be administered orally, injected into a vein or muscle to enter the bloodstream and reach mesothelioma cells throughout the body, or it can be placed directly into the affected area of the body to mainly affect mesothelioma cells in that area. Sometimes doctors use more than one chemotherapy drug. This is called combination chemotherapy.