Types of Mesothelioma
Based on the location of the tumor development, mesothelioma is most commonly divided into four different categories. These include:
Pleural: This form of cancer develops in the chest cavity and comprises about 75 percent of all mesothelioma cases.
Peritoneal: This form of cancer develops in the abdomen and accounts for about 20 percent of the cases of mesothelioma.
Pericardial: Developing around the heart, this form of cancer is rare and accounts for only about five percent of the mesothelioma cases seen.
Testicular: Extremely rare, this form of cancer can be seen in less than one percent of all mesothelioma patients.
Based on the cell appearance under a microscope, mesothelioma can also be divided into four different main categories. The American Cancer Society explains these include:
Epithelioid: The most commonly seen form of this cancer, this form tends to give patients a better prognosis than the other varieties.
Sarcomatoid, or Fibrous: Only about 10 to 20 percent of mesothelioma cancer cases are this type.
Mixed, or Biphasic: Around 30 to 40 percent of mesothelioma types are this cancer. It possesses features of both epithelioid and sarcomatoid mesothelioma.
Desmoplastic: This is a rare form of mesothelioma.
Characteristics
Mesothelioma is characterized by its low rate of successful treatment. This can be greatly explained by the delay in its development, known as latency, and its easily-overlooked symptoms. In fact, early symptoms of mesothelioma are virtually non-existent. With generic symptoms that develop slowly and mimic many other illnesses, mesothelioma is rarely diagnosed quickly in patients. Symptoms of pleural mesothelioma typically include shortness of breath, difficulty swallowing, or a persistent cough. Peritoneal mesothelioma patients may experience fatigue, nausea, the development of lumps under the skin, abdominal swelling, or pain. Pericardial mesothelioma symptoms may appear as chest pain, a cough, irregular heartbeat or fatigue. As a result of its rarity, little is known about the symptoms of testicular mesothelioma.
This slow recognition of mesothelioma helps explain its lethal quality. Like most diseases, mesothelioma is best treated in its earliest stages, when tumors are localized and the patient is healthiest. However, this is rarely possible and patients must resort to seeking treatment as their health begins to noticeably fail. Adding to the difficulty of treating this disease, many options, like surgery, are no longer available when this cancer is found in its late stages. Patient age and level of health determine the treatments available, and on account of the advanced age of most mesothelioma patients, a full range of treatments is rarely available.
Mesothelioma Causes
Mesothelioma is a very deadly form of cancer made up of four main types, which impact 2,000 to 3,000 Americans every year. The first form of this disease is pleural mesothelioma, which develops in the lining of the lungs. This cancer of the lungs can cause many serious side-effects, including hoarseness, shortness of breath, fluid buildup in the lungs, sharp chest pains, coughing up blood, a loss of muscle function, and extreme swelling. Pleural mesothelioma makes up for the highest percentage of mesothelioma cases.
The two less common kinds of mesothelioma are peritoneal and pericardial mesothelioma. Peritoneal mesothelioma is a cancer that affects the lining of the abdomen and may develop when patients cough up, then swallow inhaled asbestos fibers. Symptoms of this cancer include intense stomach pain, abnormal weight loss, ruptures of the abdomen, vomiting, and a buildup of fluid in the abdominal region. Pericardial mesothelioma is a cancer that affects the lining of the heart. Symptoms of this disease include shortness of breath and sharp chest pains.
The final form of mesothelioma involves tumors found in the tunic vaginalis, known as testicular mesothelioma. This extremely rare form of mesothelioma is characterized by the development of tumors which begin in the covering layer of the testicles. In many cases, this testicular form of mesothelioma is secondary, with the main form of the cancer being located elsewhere in the patient.
Causes of Mesothelioma
The main cause of mesothelioma is exposure to asbestos, a naturally-occurring material created through the amalgamation of several different minerals with fiber-like structures. These fibers are extremely friable and hard, allowing them to break into tiny pieces that can enter the body and burrow into internal tissues. Until very recently, asbestos saw heavy usage and was a popular and cost effective component of a number of construction materials and consumer products. In addition to its low cost, its popularity largely derived from the material’s strong resistance to heat, chemicals and electricity.
However, the 1960s saw the discovery and publication of the extremely negative effects that exposure to asbestos can have on an individual’s health. Among these negative side effects was the development of mesothelioma, which can impact those exposed for decades after. Although most usage stopped after 1989 legislation regulated the use of asbestos, it is still permitted in some products. Furthermore, the long latency period of this disease means individuals might not be aware of past exposure for as many as five decades later, when symptoms finally begin to appear.
Exposure to Asbestos
Exactly how asbestos causes mesothelioma has yet to be fully explained. A number of competing theories have been introduced by scientists to account for this causation. One theory states that asbestos fibers may scar certain cells in the protective lining of organs, known as the mesothelium, eventually leading to the development of cancer.
Another popular theory states that asbestos fibers have properties that can change the normal structure of cells in the body. The theory states that the fibers can corrupt the natural ability of these cells to divide at a healthy rate. This new unnatural cell division then produces this form of cancer.
What is not disputed, however, is the fact that exposure to asbestos causes every form of mesothelioma. This much has been proven scientifically by a staggering amount of evidence showing a strong correlation between exposure length and intensity and mesothelioma development.
Who Is at Risk for Developing Mesothelioma?
Studies have shown that certain individuals are at a higher risk of developing mesothelioma than others. One such group of people are individuals who underwent high amounts of radiation exposure. The American Cancer Society also explains that most cases of mesothelioma have been linked to workplace asbestos exposure, which was common in the past. However, because this material can attach to clothing and hair and travel with these laborers, anyone who comes in contact with them may be at risk, including relatives at home. Furthermore, many schools, homes, commercial buildings and industrial factories were constructed with or hold asbestos-containing products, putting individuals who frequent these locations at risk as well.
Additional Risk Factors
Radiation – The Department of Internal Medicine in Philadelphia did a study regarding malignant mesothelioma occurrences following radiation therapy. A case of pleural mesothelioma was found in a patient who successfully completed radiation therapy for Hodgkin’s disease. It is important to note that this patient had no prior exposure to asbestos.
With long-term cancer survival rates increasing, a light has been shed regarding concerns for neoplastic complications. While the causes of malignancies are probably due to numerous factors, radiation therapy and chemotherapy have been implicated in the development of post-therapy neoplasia (new cell growth).
Zeolite - A silicate mineral chemically similar to asbestos has been found in the soil of the Anatoli region of Turkey. Zeolite has been the reported cause of a few mesothelioma cases in that region.
Thorium dioxide - This chemical has not been used for many years because of the found link between the toxin and cancer. There have been a handful of cases where mesothelioma was found in patients after using x-ray imaging.
Other factors that may be potential risk factors include chronic imflamation, chest injuries, genetics and organic chemicals. These factors are not well researched and require further study before a causal relationship can be determined.
Tobacco Use and Mesothelioma
It has been proven that smoking alone does not cause mesothelioma, unless the cigarettes used asbestos filters. However, smoking can damage the lungs, reducing the body’s ability to stave off the negative effects of asbestos exposure, including the unique form of cancer, mesothelioma. For this reason, smokers see an even higher risk of suffering from the cancer.
Mesothelioma Resources
Getting a diagnosis of mesothelioma can be a daunting time for a patient and his or her loved ones. Patients may have countless questions running through their head and want answers. Mesotheliomasymptoms.com has a resource that has answers. Written by Michael Todd Sapko MD, PhD, the mesothelioma E-book addresses information regarding symptoms, diagnosis and treatment of this devastating disease. Download your free copy of this book here.
Additionally, anyone affected by mesothelioma is urged to get a Mesothelioma Information Packet delivered free of charge to their residence within 24 hours. For any further questions call 1-855-584-0411.
References:
The American Cancer Society.
EPA.
Pub Med.
emedicinehealth
