Asbestos lung cancer is a group of diseases related to asbestos exposure. While the term itself is technically incorrect — only one of the diseases belonging to this group (asbestosis) originates in the lungs (and it is not a form of cancer) — it serves as a way of classifying asbestos-related diseases that affect the lungs.
Asbestos is a naturally occurring mineral that has been mined, processed, and used for more than 6,000 years. The two most common diseases related to asbestos lung cancer are asbestosis and mesothelioma, with pleural mesothelioma being the most common form of mesothelioma. Both mesothelioma and asbestosis are associated with the inhalation of asbestos and subsequent inflammation caused by the lodging of asbestos in the lungs.
Mesothelioma.
Malignant mesothelioma is a rare type of asbestos lung cancer that results from asbestos becoming lodged in the lining of the lung. However, unlike asbestosis, which originates in the lungs, mesothelioma occurs in the serous lining, which is the lining surrounding the outside of the lungs. Another thing that distinguishes mesothelioma from asbestosis is that it leads to the growth of tumors that are malignant (asbestosis leads to the growth of scar tissue, which is benign). This means that the growths in the lungs' serous membranes related to mesothelioma are cancerous, can grow rapidly and can spread to other organs. Asbestosis, on the other hand, does not spread to other organs. When cancer tumors grow and then spread to other organs, this is called metastasis.
Pleural Mesothelioma
Mesothelioma can affect several different organs in the body, not just the lungs. When mesothelioma occurs in the lungs, it is called pleural mesothelioma; when it occurs in the heart lining it is called pericardial mesothelioma; and when it occurs in the abdomen it is called peritoneal mesothelioma. Asbestos exposure is thought to be the primary cause of all three types of mesothelioma.
The timeline between asbestos exposure and the onset of pleural mesothelioma is very long (30 to 40 years). Pleural mesothelioma can be detected by x-rays, but the diagnosis of pleural mesothelioma has to be confirmed with a biopsy. The treatments for pleural mesothelioma are similar to other cancers. They include chemotherapy, radiation therapy and surgical removal of the cancerous tissues. However, it is important to note that different types of cancers respond differently to different types of treatments. As a result, a patient's treatment plan is based on his or her individual case. Unfortunately, the disease is very aggressive, and most treatments do not slow its progression. The life expectancy of those diagnosed with pleural mesothelioma is less than a year.
Asbestosis.
Asbestosis is a disease in which asbestos fibers cause scarring of the lungs; however, it is not a type of lung cancer. This disease occurs because asbestos fibers are tiny, yet durable; when they are inhaled, the lungs' natural filtration system is unable to eliminate them from the air. As a result, asbestos is able to enter the very sterile inner reaches of the lung cavities. When asbestos fibers become lodged in the interstitium — the area surrounding the lungs' air sacs (alveoli) — the lungs become inflamed, which eventually leads to scarring. The timeline between the moment asbestos enters the lungs and the eventual onset of scarring can be as long as 10 years. Eventually, if enough scarring occurs in the lungs, it will be classified as fibrosis. Asbestosis is fibrosis that forms in the interstitium.
Fibrosis is defined as the development of excess fibrous connective tissue in an organ. This connective tissue cripples the areas of the lungs that it invades. Thus, when it spreads across large areas of the lungs over time, the lungs lose their ability to function properly. Similar to pleural mesothelioma, the total timeline between exposure to asbestos and the development of large areas of fibrosis can be as long as 30 or 40 years.
Asbestosis is normally detected with an x-ray showing the large fibrous growths in the lungs. Oftentimes, the initial symptom is difficulty breathing, which may be caused by the fibrous tissue that has formed, or by a pleural effusion (buildup of fluid) caused by the asbestosis. There is no cure for asbestosis, and eventually the fibrous tissue can spread throughout the lungs and make it impossible to breath. A common cause of death related to asbestosis is congestive heart failure, in which the heart becomes overworked in its attempt to push enough blood through the lungs to carry sufficient oxygen to the rest of the body.
Monday, February 22, 2010
Types of Mesothelioma
Mesothelioma cancer affects the serous membranes that surround the major organs in the midsection of the body. Different organs can be affected by mesothelioma because the serous membranes surround the lungs, heart, abdomen and others. The most common type of mesothelioma is that which affects the lung lining, and is called pleural mesothelioma. Other types are pericardial mesothelioma, which affects the lining of the heart, and peritoneal mesothelioma, affecting the lining of the abdomen.
Mesothelioma, contrary to what many people think, is not a type of primary lung cancer. That is, mesothelioma does not originate in the lungs, but as described above, it starts in the serous membranes or lining around the lungs (or other organs). However, mesothelioma can spread to the lungs and when this occurs, it is considered to be a secondary lung cancer. Mesothelioma is also commonly referred to as an asbestos lung cancer. Technically, this is also incorrect, since mesothelioma does not originate in the lungs. Asbestosis is a type of asbestos lung disease that is often confused with mesothelioma.
Pleural Mesothelioma.
Pleural mesothelioma represents about 75% of all mesotheliomas. The disease can grow quickly and enlarge the pleural space, causing it to fill with fluid. This fluid leads to the discomfort or pain associated with first detection of the disease. It is thought that pleural mesothelioma is caused by the inhaling of fibrous materials, including asbestos. These fibers become lodged in the pleura and, over time, cause damage that can lead to cancer. Learn more about pleural mesothelioma.
Pericardial Mesothelioma.
The rarest form of mesothelioma is that which affects the linings of the heart cavity, called the pericardium. Less than 10% of all mesothelioma cases are related to the heart. As in the lung, the rapid growth of the cancerous tumors can cause expansion of the tissue and accumulation of fluid. The fluid can interfere with the functioning of the heart and cause chest pain. Mesothelioma cases are known to be caused by exposure to asbestos; but it is completely unknown how the asbestos fibers enter the tissue layers surrounding the heart. Learn more about pericardial mesothelioma.
Peritoneal Mesothelioma.
Mesothelioma of the abdomen is called peritoneal mesothelioma. The serous membrane surrounding the abdomen is known as the peritoneum. This disease accounts for approximately 10% to 20% of mesothelioma cases. In addition, a rare form of peritoneal mesothelioma affects the male testicles. The covering layer of the scrotum is actually an outpouching of the peritoneum. Peritoneal mesothelioma is due to the ingestion of fibrous materials, including asbestos. Learn more about peritoneal mesothelioma.
Mesothelioma, contrary to what many people think, is not a type of primary lung cancer. That is, mesothelioma does not originate in the lungs, but as described above, it starts in the serous membranes or lining around the lungs (or other organs). However, mesothelioma can spread to the lungs and when this occurs, it is considered to be a secondary lung cancer. Mesothelioma is also commonly referred to as an asbestos lung cancer. Technically, this is also incorrect, since mesothelioma does not originate in the lungs. Asbestosis is a type of asbestos lung disease that is often confused with mesothelioma.
Pleural Mesothelioma.
Pleural mesothelioma represents about 75% of all mesotheliomas. The disease can grow quickly and enlarge the pleural space, causing it to fill with fluid. This fluid leads to the discomfort or pain associated with first detection of the disease. It is thought that pleural mesothelioma is caused by the inhaling of fibrous materials, including asbestos. These fibers become lodged in the pleura and, over time, cause damage that can lead to cancer. Learn more about pleural mesothelioma.
Pericardial Mesothelioma.
The rarest form of mesothelioma is that which affects the linings of the heart cavity, called the pericardium. Less than 10% of all mesothelioma cases are related to the heart. As in the lung, the rapid growth of the cancerous tumors can cause expansion of the tissue and accumulation of fluid. The fluid can interfere with the functioning of the heart and cause chest pain. Mesothelioma cases are known to be caused by exposure to asbestos; but it is completely unknown how the asbestos fibers enter the tissue layers surrounding the heart. Learn more about pericardial mesothelioma.
Peritoneal Mesothelioma.
Mesothelioma of the abdomen is called peritoneal mesothelioma. The serous membrane surrounding the abdomen is known as the peritoneum. This disease accounts for approximately 10% to 20% of mesothelioma cases. In addition, a rare form of peritoneal mesothelioma affects the male testicles. The covering layer of the scrotum is actually an outpouching of the peritoneum. Peritoneal mesothelioma is due to the ingestion of fibrous materials, including asbestos. Learn more about peritoneal mesothelioma.
Introduction to Malignant Mesothelioma
Malignant mesothelioma affects the lining or membranes of certain large cavities in the body. These cavities, called the serous cavities, house certain major organs in the body including the heart, lungs, abdomen and others. The membranes that surround these cavities are called the serous membranes. They serve to protect these major organs from the friction and abrasion that occur as the organs move against each other during typical daily functioning, such as breathing and heart beating. The serous membranes derive from specialized cells called mesothelial cells. These cells form to create the mesothelium, which is the major tissue layer of the serous membranes. Cancer that occurs in the mesothelium tissue is called mesothelioma.
Malignant mesothelioma takes on three forms:
•Peritoneal mesothelioma, in the peritoneum or membrane surrounding the abdomen. A rare form of peritoneal mesothelioma can also affect the male testicles, because the lining around the scrotum is an extension of the peritoneum.
•Pericardial mesothelioma, in the perdicardium or lining surrounding the heart.
•Pleural mesothelioma, which is the most common form of malignant mesothelioma and affects the lining of the lung cavity.
All mesotheliomas are now considered to be malignant, or cancerous. They start as a localized tumor and spread rapidly to include most of the surrounding tissues and organs. Originally, fibrous cists and other non-cancerous growths that appeared in the serous membranes were thought to be mesotheliomas and were termed "benign fibrous mesothelioma" and "multicystic mesothelioma." These conditions are now known not to originate in the mesothelial cells, but other cells within the serous membranes. These conditions are typically localized, non-cancerous and do not spread rapidly.
Etiology of Malignant Mesothelioma
Most cases of malignant mesothelioma are associated with a previous exposure to fibrous minerals, of which asbestos is the most important. There is now indisputable evidence of the role of these fibers in the development of this disease. This has been demonstrated in animal experiments and many other experiments. Not everyone who is exposed to asbestos fibers has developed malignant mesothelioma, suggesting that other factors may also be involved.
Although malignant mesothelioma is rare, it is a serious, deadly disease. It is often in the advanced stages when it is detected, so the outlook for the mesothelioma patients is not as good as it is for patients with cancers that are detected earlier. The average survival time after detection is 1 to 2 years. This survival time also depends on the type of mesothelioma.
Malignant mesothelioma takes on three forms:
•Peritoneal mesothelioma, in the peritoneum or membrane surrounding the abdomen. A rare form of peritoneal mesothelioma can also affect the male testicles, because the lining around the scrotum is an extension of the peritoneum.
•Pericardial mesothelioma, in the perdicardium or lining surrounding the heart.
•Pleural mesothelioma, which is the most common form of malignant mesothelioma and affects the lining of the lung cavity.
All mesotheliomas are now considered to be malignant, or cancerous. They start as a localized tumor and spread rapidly to include most of the surrounding tissues and organs. Originally, fibrous cists and other non-cancerous growths that appeared in the serous membranes were thought to be mesotheliomas and were termed "benign fibrous mesothelioma" and "multicystic mesothelioma." These conditions are now known not to originate in the mesothelial cells, but other cells within the serous membranes. These conditions are typically localized, non-cancerous and do not spread rapidly.
Etiology of Malignant Mesothelioma
Most cases of malignant mesothelioma are associated with a previous exposure to fibrous minerals, of which asbestos is the most important. There is now indisputable evidence of the role of these fibers in the development of this disease. This has been demonstrated in animal experiments and many other experiments. Not everyone who is exposed to asbestos fibers has developed malignant mesothelioma, suggesting that other factors may also be involved.
Although malignant mesothelioma is rare, it is a serious, deadly disease. It is often in the advanced stages when it is detected, so the outlook for the mesothelioma patients is not as good as it is for patients with cancers that are detected earlier. The average survival time after detection is 1 to 2 years. This survival time also depends on the type of mesothelioma.
What are the main causes of mesothelioma?
Mesothelioma is most predominantly caused by asbestos exposure. Asbestos fibers that are inhaled through the mouth and nose may eventually become embedded in the lining of the lungs, causing damage and resulting in lung cancer or asbestosis (scar tissue formation in the lungs). It has also been found that swallowing asbestos fibers could contribute to a form of mesothelioma originating in the abdomen called peritoneal mesothelioma.
Mesothelioma generally results from occupational exposure but there are instances of environmental exposure to asbestos that can cause the disease. Oftentimes second hand exposure of a family member to an asbestos workers dirty work clothes can result in that family member developing mesothelioma.
Asbestos insulation workers appear to have the highest death rate. One study reports that almost six percent of asbestos workers fall victim to mesothelioma and asbestos insulation workers are over 300 times more likely to die from mesothelioma than the general public.
Mesothelioma generally results from occupational exposure but there are instances of environmental exposure to asbestos that can cause the disease. Oftentimes second hand exposure of a family member to an asbestos workers dirty work clothes can result in that family member developing mesothelioma.
Asbestos insulation workers appear to have the highest death rate. One study reports that almost six percent of asbestos workers fall victim to mesothelioma and asbestos insulation workers are over 300 times more likely to die from mesothelioma than the general public.
Mesothelioma Information
As with any disease or health condition, mesothelioma researchers have, over time, collected statistical information about mesothelioma. These statistics can help us learn about the proclivities of the disease and its incidence and potentially help future patients as we learn more about mesothelioma.
Incidence of Diagnosis.
New cases of mesothelioma are diagnosed in between 2,500 and 3,000 Americans each year. These numbers, while significant, would indicate that mesothelioma is still a relatively rare disease, though incidence is expected to rise in the next decade according to projections.
Age at Diagnosis
The first diagnosis of mesothelioma typically occurs in men and women between the ages of 50 and 70 years. Mesothelioma patients, certainly, have been diagnosed at ages younger than 50 and older than 70, but diagnoses for those age groups are considered statistical anomalies.
Does Mesothelioma Occur in a Particular Sex or Racial Demographic More than Another?
Mesothelioma is much more common in men than women, due mostly to occupational asbestos exposure being more common among men of industrial labor sites. That is not to say, however, that women cannot be diagnosed with mesothelioma. In fact, recent evidence suggests that mesothelioma incidence in women may rise in the coming years as secondary exposures to asbestos can manifest in the form of a positive mesothelioma diagnosis. Also of note is that mesothelioma is much less common among African Americans than white Americans, the reasons for which researchers are still investigating.
What are Typical Patient Survival Rates Following a Mesothelioma Diagnosis?
As mesothelioma is often diagnosed in its advanced stages, the prognosis is sometimes poor with life expectancy being little more than a year following diagnosis. If diagnosed early enough however, patient prognoses increase dramatically. Patient survival rates are often contingent on the treatments available to the particular patient. Early-stage tumors eligible for surgical resection, for instance, will result in improved prognoses over those diagnosed with later-stage disease. As new therapies and treatments are researched and employed in the future, it is realistic to anticipate an improvement in patient survival rates.
Incidence of Diagnosis.
New cases of mesothelioma are diagnosed in between 2,500 and 3,000 Americans each year. These numbers, while significant, would indicate that mesothelioma is still a relatively rare disease, though incidence is expected to rise in the next decade according to projections.
Age at Diagnosis
The first diagnosis of mesothelioma typically occurs in men and women between the ages of 50 and 70 years. Mesothelioma patients, certainly, have been diagnosed at ages younger than 50 and older than 70, but diagnoses for those age groups are considered statistical anomalies.
Does Mesothelioma Occur in a Particular Sex or Racial Demographic More than Another?
Mesothelioma is much more common in men than women, due mostly to occupational asbestos exposure being more common among men of industrial labor sites. That is not to say, however, that women cannot be diagnosed with mesothelioma. In fact, recent evidence suggests that mesothelioma incidence in women may rise in the coming years as secondary exposures to asbestos can manifest in the form of a positive mesothelioma diagnosis. Also of note is that mesothelioma is much less common among African Americans than white Americans, the reasons for which researchers are still investigating.
What are Typical Patient Survival Rates Following a Mesothelioma Diagnosis?
As mesothelioma is often diagnosed in its advanced stages, the prognosis is sometimes poor with life expectancy being little more than a year following diagnosis. If diagnosed early enough however, patient prognoses increase dramatically. Patient survival rates are often contingent on the treatments available to the particular patient. Early-stage tumors eligible for surgical resection, for instance, will result in improved prognoses over those diagnosed with later-stage disease. As new therapies and treatments are researched and employed in the future, it is realistic to anticipate an improvement in patient survival rates.
What is mesothelioma?
Malignant mesothelioma is the most serious of all asbestos-related diseases. Although uncommon, mesothelioma is no longer considered rare. Mesothelioma is a cancer that is particulary difficult for doctors to diagnose and one that does not respond well to therapy.
The chest cavity, abdominal cavity, and the cavity around the heart are surrounded by a a layer of specialized mesothelial cells. Most other internal organs are also covered by these cells. The tissue formed by these cells is called mesothelium.
A special protective lubricating fluid that allows organs to move around is produced by the mesothelium. This protective fluid helps the lungs to move without resistance inside the chest cavity while breathing. The medical name for the mesothelium of the chest is the pleura and the medical name for the mesothelium of the abdomen is the peritoneum. The mesothelium of the "sac-like" space around the heart is called the pericardium.
A malignant (cancerous) tumor of the mesothelium is called a malignant mesothelioma. As most mesothelial tumors are cancerous, malignant mesothelioma is often simply called mesothelioma. Tumors of the mesothelium can also be benign (noncancerous) but benign mesotheliomas are much more rare.
Mesothelioma was recognized as a tumor of the pleura, peritoneum and pericardium in the late 1700's. However it was not until much later, in 1960, that this particular type of tumor was described in more detail and even more importantly, its association with asbestos exposure was recognized. The first report linking mesothelioma to asbestos exposure was written by J.C.Wagner, and described 32 cases of workers in the "Asbestos Hills" in South Africa. Since than the relationship between mesothelioma and asbestos exposure has been confirmed in studies around the world.
The incidence of mesothelioma in the United States remains very low, with 14 cases occurring per million people per year. Despite these numbers the noticed threefold increase in mesothelioma in males between 1970 and 1984, is directly associated with environmental and occupational exposure to asbestos, mostly in areas of asbestos product plants and shipbuilding facilities.
Although the disease is much more commonly seen in 60-year old men, it has been described in women and early childhood as well. The cause of the disease is not so well understood in these latter two groups, but there is some evidence of possible asbestos exposure for some of these cases as well.
Malignant mesotheliomas are divided into three main types. About 50% to 70% of mesotheliomas are the epithelioid type. This type has the best prognosis (outlook for survival). The other two types are the sarcomatoid type (7%-20%), and the mixed/biphasic type (20%-35%). Treatment options for all three types are the same.
About three-fourths of mesotheliomas start in the chest cavity. They are known as pleural mesothelioma. Another 10% to 20% begin in the abdomen. These are called peritoneal mesothelioma. Pericardial mesothelioma, starts in the cavity around the heart, and is very rare. The covering layer of the testicles is actually an outpouching of peritoneum into the scrotum. Mesotheliomas that affect this covering of the testicles are quite rare.
The chest cavity, abdominal cavity, and the cavity around the heart are surrounded by a a layer of specialized mesothelial cells. Most other internal organs are also covered by these cells. The tissue formed by these cells is called mesothelium.
A special protective lubricating fluid that allows organs to move around is produced by the mesothelium. This protective fluid helps the lungs to move without resistance inside the chest cavity while breathing. The medical name for the mesothelium of the chest is the pleura and the medical name for the mesothelium of the abdomen is the peritoneum. The mesothelium of the "sac-like" space around the heart is called the pericardium.
A malignant (cancerous) tumor of the mesothelium is called a malignant mesothelioma. As most mesothelial tumors are cancerous, malignant mesothelioma is often simply called mesothelioma. Tumors of the mesothelium can also be benign (noncancerous) but benign mesotheliomas are much more rare.
Mesothelioma was recognized as a tumor of the pleura, peritoneum and pericardium in the late 1700's. However it was not until much later, in 1960, that this particular type of tumor was described in more detail and even more importantly, its association with asbestos exposure was recognized. The first report linking mesothelioma to asbestos exposure was written by J.C.Wagner, and described 32 cases of workers in the "Asbestos Hills" in South Africa. Since than the relationship between mesothelioma and asbestos exposure has been confirmed in studies around the world.
The incidence of mesothelioma in the United States remains very low, with 14 cases occurring per million people per year. Despite these numbers the noticed threefold increase in mesothelioma in males between 1970 and 1984, is directly associated with environmental and occupational exposure to asbestos, mostly in areas of asbestos product plants and shipbuilding facilities.
Although the disease is much more commonly seen in 60-year old men, it has been described in women and early childhood as well. The cause of the disease is not so well understood in these latter two groups, but there is some evidence of possible asbestos exposure for some of these cases as well.
Malignant mesotheliomas are divided into three main types. About 50% to 70% of mesotheliomas are the epithelioid type. This type has the best prognosis (outlook for survival). The other two types are the sarcomatoid type (7%-20%), and the mixed/biphasic type (20%-35%). Treatment options for all three types are the same.
About three-fourths of mesotheliomas start in the chest cavity. They are known as pleural mesothelioma. Another 10% to 20% begin in the abdomen. These are called peritoneal mesothelioma. Pericardial mesothelioma, starts in the cavity around the heart, and is very rare. The covering layer of the testicles is actually an outpouching of peritoneum into the scrotum. Mesotheliomas that affect this covering of the testicles are quite rare.
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