Tuesday, September 6, 2011
What is Mesothelioma
Mesothelioma, more precisely malignant mesothelioma, is a rare form of cancer that develops from the protective lining that covers many of the body's internal organs, the mesothelium. It is usually caused by exposure to asbestos.
Its most common site is the pleura (outer lining of the lungs and internal chest wall), but it may also occur in the peritoneum (the lining of the abdominal cavity), the pericardium (a sac that surrounds the heart), or the tunica vaginalis (a sac that surrounds the testis).
Most people who develop mesothelioma have worked on jobs where they inhaled asbestos and glass particles, or they have been exposed to asbestos dust and fiber in other ways. It has also been suggested that washing the clothes of a family member who worked with asbestos or glass can put a person at risk for developing mesothelioma. Unlike lung cancer, there is no association between mesothelioma and smoking, but smoking greatly increases the risk of other asbestos-induced cancers. Those who have been exposed to asbestos have collected damages for asbestos-related disease, including mesothelioma. Compensation via asbestos funds or lawsuits is an important issue in law practices regarding mesothelioma (see asbestos and the law).
The symptoms of mesothelioma include shortness of breath due to pleural effusion (fluid between the lung and the chest wall) or chest wall pain, and general symptoms such as weight loss. The diagnosis may be suspected with chest X-ray and CT scan, and is confirmed with a biopsy (tissue sample) and microscopic examination. A thoracoscopy (inserting a tube with a camera into the chest) can be used to take biopsies. It allows the introduction of substances such as talc to obliterate the pleural space (called pleurodesis), which prevents more fluid from accumulating and pressing on the lung. Despite treatment with chemotherapy, radiation therapy or sometimes surgery, the disease carries a poor prognosis. Research about screening tests for the early detection of mesothelioma is ongoing.
Mesothelioma Types
How are different types of mesothelioma classified?
Types of Mesothelioma by Site
Pleural Mesothelioma
Malignant pleural mesothelioma often originates within the chest cavity and can, at times, involve the lung. This particular form of mesothelioma can metastasize to numerous organs in the body - even the brain - and tends to do so more frequently than not.
Pleural mesothelioma is not always easily detectable. Frequently, in the early stages of the disease, such as stage 1 mesothelioma, symptoms may be mild. Patients usually report pain in one area of the chest that never seems to go away, weight loss and fever. Occasionally, other symptoms are more severe and include problems with breathing due to fluid build up in the chest. A CT Scan of the chest area has proven to be the best test for identifying how far along the disease has progressed.
Frequently serum markers are used to diagnose of various forms of cancer. Mesothelioma cannot be diagnosed using this method as no serum markers currently exist. If high levels of hyaluronic acid are present it may be possible to distinguish mesothelioma types from other types of cancer or to determine the effectiveness of a treatment protocol.
The mesothelioma survival rate for patients diagnosed with pleural mesothelioma typically is not high as patients often do not live beyond seventeen months from the onset of symptoms. Only 8% of those with a mesothelioma diagnosis will live three to five years from the onset of mesothelioma symptoms.
Peritoneal Mesothelioma
Peritoneal mesothelioma originates in the abdomen and will frequently spread to other organs in area including the liver, spleen or bowel. Severe abdominal pain is the most common complaint that patients present to mesothelioma doctors. There may also be a discomfort level with fluid buildup in the abdomen as well. Other symptoms of peritoneal mesothelioma may include difficult bowel movements, nausea and vomiting, fever and swollen feet.
The survival rate is even worse for those diagnosed with peritoneal mesothelioma with patients typically surviving only ten months from the time that they first started experiencing the symptoms noted above.
Pericardial Mesothelioma
Pericardial mesothelioma is the least common form of mesothelioma. Pericardial mesothelioma, as the name suggests, involves the heart. This rare type of mesothelioma cancer invades the pericardium, the sac that surrounds the heart. As the cancer progresses, the heart is not able to deliver oxygen as efficiently to the body causing further decline in health at an increasingly rapid rate. The symptoms most commonly associated with pericardial mesothelioma mimic those of a heart attack: nausea, pain in the chest and shortness of breath.
Types of Mesothelioma Tumors
Malignant Mesothelioma
Malignant mesothelioma is an uncommon form of cancer and of all asbestos related diseases, the most serious. The symptoms associated with the disease make it difficult for doctors to diagnose. Often, by the time that a proper diagnosis is made, the disease has progressed to a point where patients do not respond well to treatment therapy. Malignant mesothelioma is caused almost exclusively by the inhalation of airborne asbestos particles. Another unique factor associated with the disease is that there can be a long latency periodbetween the time of asbestos exposure and the actual manifestation of the disease in the form of malignant mesothelioma.
Benign Mesothelioma
Benign mesothelioma, or non-malignant mesothelioma, is much easier to treat than the malignant form of the cancer and can be treated successfully in many cases.
Mesothelioma Cell Types
Epithelial Mesothelioma
Epithelial Mesothelioma is the most common cell type and accounts for approximately 50-75% percent of all diagnosed cases each year. These cells are uniform in shape, with an elongated pattern that makes them easily distinguishable when viewed under high magnification. These types ofcancercells are adenocarcinomas, malignancies which are more commonly associated with pure lung cancers as opposed to cancers of the mesothelium.
Sarcomatoid Mesothelioma
Sarcomatoid mesothelioma is a less common cell type, accounting for between 7 and 20% of mesothelioma cases each year. These cells grow forth out of supportive structures, such as muscles and bones.
Biphasic Mesothelioma
Biphasic mesotheliomas are those with a mix of epithelial and sarcomatoid cell types.Mesothelioma treatment options do not vary greatly for different cell types, but often sarcomatoid mesotheliomas are more difficult to treat as a result of the surrounding affected tissues that they spread from.