Types of Mesothelioma

Types of Mesothelioma

Types of Mesothelioma

Many people think of mesothelioma as a disease of the lungs, but that is not always the case. Mesothelioma is a type of cancer that is generally caused by asbestos exposure. It can can be diagnosed in anyone who has been exposed to asbestos, even briefly, but is more common in those who were exposed to high levels of the toxic substance, or who worked around it for years. It can take 20 to 50 years after the exposure began for the individual to develop any mesothelioma symptoms.

Asbestos fibers are microscopic, sharp and easy to inhale. After being inhaled, these fibers can lodge in any area of the body that has a special protective lining, called a mesothelium. The mesothelium forms a double membrane which both lines the inner body cavities and covers the organs. The lungs, heart, stomach and testes are all protected by a mesothelial layer, and their natural movement is aided by the production of a special fluid produced by the mesothelium.

Pleural Mesothelioma

Pleural mesothelioma, which is one of the most common asbestos-related cancers, develops in the pleural mesothelium, the membrane that lines the lungs and the inside of the chest cavity. Pleural mesothelioma can be extremely difficult to diagnose, both because of its decades-long latency period, and because its symptoms tend to be non-specific. Shortness of breath, coughing, chest pain and fatigue are associated with a number of common respiratory conditions, including the common cold, emphysema, bronchitis and asthma. Occasionally, a patient experiencing these symptoms may feel that they are just getting over a mild virus, or even just getting older, and therefore avoid consulting their physician. When they do seek medical attention, the doctor may not suspect mesothelioma unless there is known asbestos exposure in the patient's past. Many cases of pleural mesothelioma are initially misdiagnosed.

Peritoneal Mesothelioma

Peritoneal mesothelioma is the second most common type of cancer caused by asbestos exposure. Doctors are not completely sure how the asbestos fibers make their way into the abdominal cavity, but one plausible explanation involves asbestos dust falling into the victim’s food or beverage, and then being ingested. Others have hypothesized that the fibers can travel through either the bloodstream or the lymphatic system after being inhaled. In any case, the fibers lodge themselves inside the abdominal lining and begin to develop tumors. Like pleural mesothelioma, peritoneal mesothelioma is very difficult to diagnose because of the range of non-specific symptoms that it can cause. Patients may experience pain, bloating and in some cases, shortness of breath.

Pericardial Mesothelioma

Pericardial mesothelioma is one of the rarest types of mesothelioma. Again, the genesis of this cancer is not precisely understood, but it is known the asbestos fibers can penetrate the pericardium, or the membrane around the heart, which then develops scar tissue as a result of the constant invasion of these fibers. This scar tissue builds up, eventually interfering with normal heart function, in addition to fostering the formation of a cancerous tumor. Some symptoms of pericardial mesothelioma include an irregular heartbeat and heart palpitations, as well as chest pain and difficulty breathing.

Many cases of both peritoneal and pericardial mesothelioma are discovered only when the patient's physician is conducting screening or surgery for an unrelated condition.

Another form of mesothelioma involves the testicular lining. Testicular mesothelioma is the rarest form of mesothelioma, with under 100 confirmed diagnoses. Because this cancer is so rare, it is difficult to determine what the actual symptoms are. The most apparent include testicular lumps or swelling in the scrotum area. Doctors simply do not know how the asbestos fibers are absorbed into the testicular lining.

Mesothelioma is aggressive cancer. Treatment may include surgery, chemotherapy, and radiation, but they are less effective than in other types of cancer. Also, because the fibers are embedded in the body’s lining, the tumors will keep appearing and most likely become malignant. Another obstacle with mesothelioma is an accurate and timely diagnosis. The latency period is so extensive, the fibers have had plenty of time to wreak havoc on the body’s lining before ever causing any symptoms.

Men have a much higher rate of mesothelioma than women. This can be attributed to the 27.5 million jobs, most of which were traditionally held by men, that dealt with asbestos during the 40-year span of its peak usage. Family members who lived with an asbestos worker are at a higher-than-average risk of developing mesothelioma, as well, because asbestos fibers can be carried home on clothing

Prognosis of mesothelioma

Mesothelioma Prognosis

Mesothelioma is the cancer of the mesothelium - the thin layer of tissue that lines body cavities and organs like the lungs and heart. The cancer is rare but highly aggressive. Nine out of ten times, it is caused by asbestos exposure. The other 10 percent of cases usually have had suspected but unconfirmed exposure to asbestos.

Asbestos fibers are tiny, and can noticeably be breathed in or swallowed. They lodge themselves in the deepest crevices of the lungs, damaging sensitive tissue, and they can often find their way to the mesothelium. There, they change otherwise normal cells into cancerous ones, inducing mutations that force them to grow uncontrollably and without order. This growth creates a tumor which can eventually kill a patient.

Mesothelioma Detection

As with any cancer, early detection of mesothelioma is the key to a good prognosis. Unfortunately, in most cases, it is not diagnosed until it reaches its later stages. This is because symptoms often take 20 to 50 years to develop after the initial asbestos exposure. Once symptoms do appear, cancer has already taken hold, and it is usually too late to do anything - it might already have metastasized (spread to distant regions of the body), and the tumor might not be responsive to chemotherapy. Additionally, mesothelioma mimics other diseases with its symptoms, so the disease is often misdiagnosed. Proper treatments are therefore usually delayed until the diagnosis is corrected.

Mesothelioma Life Expectancy

While there are certainly a few cases of people living relatively long and healthy lives after diagnosis and treatment for mesothelioma, prognoses are generally very poor. According to the American Cancer Society, the five-year survival rate of patients diagnosed with malignant mesothelioma is approximately 10 percent. This rate is only an average, and changes are based on a variety of factors, including what stage cancer achieved when it was detected and the type and efficacy of the treatments administered.

Age of onset is also an important factor in determining a patient's prognosis. Younger patients tend to be healthier so they can withstand the stresses that chemotherapy, surgery, and radiation therapy can place on the body. Since they recover quicker and heal faster, more aggressive treatments can be implemented.

The type of mesothelioma that a patient is diagnosed with can also have an effect on his or her prognosis. The very common type of the disease is pleural mesothelioma. In pleural mesothelioma, the cancer is in the lining of the body cavity that surrounds the lungs. Other forms of the disease include peritoneal mesothelioma - where cancer affects the lining of the lining of the abdominal cavity - and pericardial mesothelioma, the cancer of the lining of the heart. All three of these are equally deadly, but since pleural mesothelioma is the most common, it is the most frequently studied, resulting in more treatments existing for it.

Lastly, cell type appears to have an effect on the life expectancy, and thus the prognosis, of mesothelioma patients. Differently shaped cancerous cells, as determined by a pathologist, seem to have different properties and different consequences for a patient. Epithelioid cells appear to have the best prognoses, while sarcomatoid and biphasic cells have worst ones.