Mesothelioma - The 3 Main Types

In general, mesothelioma is a rare form of cancer. Different types of mesothelioma are distinguished between by where the cancer is growing. Pleural mesothelioma, the most common, accounting for 75% of all mesothelioma cases, is where cancerous cells develop on the lining of the lungs. The next most common form of mesothelioma is peritoneal mesothelioma and this is where cancerous cells grow on the peritoneum which is the lining of the abdomen. Pericardial mesothelioma, the least common major form of mesothelioma, makes up roughly 5% of all mesothelioma cases. This is where malignant cancer cells grow on the lining of the heart.

All three of these forms of mesothelioma are caused by asbestos. Asbestos is a naturally occurring fibrous mineral that was discovered around the 1860s. Due to its highly useful property of being fireproof, asbestos was used greatly in construction in the 1920s, 1930s and 1940s. It was not until the early 1960s when the severe health hazards that asbestos causes were discovered, that asbestos stopped being used. When exposed to asbestos with insufficient protection a person will breathe in tiny asbestos fibres which are suspended in the air. These fibres pass into the respiratory system until they become lodged in the lining of the lungs. Over time, an accumulation of these asbestos fibres in the lungs can cause pleural mesothelioma. Asbestos fibres may also pass into the lymphatic system and be transported to either the lining of the abdomen or the tissue surrounding the heart. This may cause either peritoneal mesothelioma or pericardial mesothelioma.

In terms of symptoms, the three main types of mesothelioma have some symptoms in common with each other. These symptoms are usual of all three types: chest pain, shortness of breath, coughing, coughing up blood, vomiting, nausea, weight loss and loss of appetite. An additional symptom of pericardial mesothelioma is palpitations.

There are a few treatments for all types of mesothelioma but none of these have a high success rate. The effectiveness of the treatment depends on how early and how aggressively the cancer is treated. If the cancerous cells are treated when they have fully matured and developed then it is unlikely that treatment methods will be successful. Treatment methods include chemotherapy which is the use of drugs to kill the cancer, radiation therapy which uses a radiation dosage to kill off cancerous cells and surgery which attempts to gain long term control over the cancer by removing a large portion of malignant cells. These treatment methods can be combined in the form of dual therapy.

Malignant Mesothelioma - Types, Causes, Stages and Treatment Options

Malignant mesothelioma is an uncommon form of cancerous tumors originating in the body tissue known as the mesothelium. The mesothelium is a specialized layer of cells that line and protect many internal organs such as the chest and abdominal cavities.

Types of Malignant Mesothelioma

The first type of malignant mesothelioma is called Pleural Mesothelioma or mesothelioma of the pleura. It is the most common type of mesothelioma making up approximately 75% of all mesothelioma cases. The pleura is a thin serous membrane found between the lungs and the chest cavity that provides a lubricated surface preventing the lungs from chafing against the chest walls. It also serves as a protective layer.

The second most common type of mesothelioma is Peritoneal Mesothelioma, also known as mesothelioma of the peritoneum. The peritoneum is a thin serous membrane that encloses the organs of the abdomen. Peritoneal Mesothelioma is a rare form of malignant mesothelioma cancer. This disease accounts for approximately 10% to 20% of all mesothelioma cases. It tends to be a more invasive form of cancer; patients diagnosed with this disease have a shorter life expectancy than if they had attracted Pleural Mesothelioma.

The third and least common type of mesothelioma is pericardial mesothelioma also known as mesothelioma of the pericardium. It accounts for less than 10% of all mesothelioma cases. The pericardium (heart sac) is the serous membrane that surrounds and protects the heart.

There are about 2,200 new cases of malignant mesothelioma of the visceral pleura each year. Mesothelioma is difficult to diagnose and is rarely curable. The most common symptoms are dyspnea and chest wall pain.

Causes Asbestos is the predominant cause of malignant mesothelioma of the visceral pleura. The period between the time of exposure to asbestos and the onset of symptoms is about 20 to 50 years. Because of this late onset, it occurs most commonly in the later years of life. It also occurs more often in men than in women.

Diagnosis

Doctors usually make an incision through the chest wall and insert an instrument called a thoracoscope between two ribs to view the area. Doctors will then do a biopsy to select a tissue sample that can be analyzed under a microscope.

Stages of Mesothelioma

Stage I: The cancer is found in the lining of the chest cavity near the lung and heart or in the diaphragm or the lung.

Stage II: The cancer has spread beyond the lining of the chest to lymph nodes in the chest.

Stage III: Cancer has spread into the chest wall, center of the chest, heart, through the diaphragm, or abdominal lining, and in some cases into nearby lymph nodes.

Stage IV: Cancer has spread to distant organs or tissues.

Treatment Radiation and radiotherapy are used in situations where the cancer is localized at the point of origin. Chemotherapy is used in more advanced stages of malignant mesotheliomas.

Cytoreductive surgery plus hyperthermic (heated) chemotherapy improves the survival and quality of life for patients with peritoneal metastases (tumors involving the lining of the abdomen).

Surgery is the option used for Stage I malignant mesothelioma. For stages II to IV, treatment by surgery is still evolving.