Surgical Treatment for mesothelioma

Surgery is commonly used in the treatment of malignant mesothelioma. The doctor may remove part of the lining of the chest or abdomen and some of the tissue around it. Sometimes part of the diaphragm, the muscle below the lungs that helps with breathing, is also removed. Depending on how far the cancer has spread, a lung also may be removed (pneumonectomy). The following are some of the most commonly used surgical treatments of mesothelioma:

Pleurodesis

Pleurodesis is a treatment administered through a thoracoscopy or existing chest tube. Pleurodesis creates inflammation effectively eliminating the pleural space. The elimination of this space then inhibits the accumulation of a pleural effusion. Generally used when the pleural effusion is symptomatic. Talc is used most commonly and effectively for this procedure, thus it is often referred to as "talcing" or as a patient having been "talced."

Pleurectomy

Surgery to remove part of the chest (pleura) or abdomen lining (peritoneum) and some of the tissue surrounding it. This procedure is performed for a variety of disorders including pleural effusion, malignant pleural mesothelioma, and trauma.

Pleurectomy/decortication

Surgery to remove part of the chest (pleura) or abdomen lining (peritoneum) and as much for the tumor mass as possible. This procedure may be performed to reduce pain caused by the tumor mass or to prevent the recurrence of pleural effusion. For peritoneal mesothelioma, surgery is generally aimed at relieving symptoms, such as recurrent ascites or bowel obstruction. As with pleural mesothelioma, complete surgical removal of the entire tumor is unlikely.

Pneumonectomy (new-mo-NEK-to-me)

Surgery to remove a lung.

Extrapleural pneumonectomy (or EPP)

Surgery to remove the pleura, diaphragm, pericardium, and entire lung involved with the tumor.

Mesothelioma Treatment

Conventional Therapies

Conventional mesothelioma therapies include surgery, radiation and chemotherapy. You should keep in mind that if you choose one course of action for mesothelioma treatment, you may preclude other courses. All of your options should be considered as soon as possible.

Alternative Treatments

Many of those being treated for serious illness find comfort in different alternative therapies such as massage and acupuncture. These untraditional methods of disease management can complement conventional therapies and allow the patient to be more at peace and comfortable during this difficult time. Meditation and Yoga are common methods used by many to reach a state of relaxation, and release endorphins, our body's natural pain relievers.

Experimental Therapies

Several forms of mesothelioma treatment such as the drug Alimta®, gene therapy, immunotherapy, photodynamic therapy and multimodality therapy are still in their experimental stages. We invite you to read the following articles on experimental therapies for malignant mesothelioma.

Treatment by Stage

This section lists typical treatment strategies based on the stage (using the Butchart staging system) of a pleural mesothelioma.

Cancer centres

Top Cancer Centers for mesothelioma treatment have been listed alphabetically by state for your convenience. Listings include contact information and Web site links where available.

Clinical Trials

Information about current studies of promising new or experimental mesothelioma treatments.

Mesothelioma symptoms

Mesothelioma symptoms are not specific to the disease; that is, many mesothelioma symptoms are also symptoms of other medical problems. Most studies show that the symptoms of mesothelioma usually begin to appear 30 to 40 years after exposure to asbestos. Thus, many mesothelioma patients are unaware that the symptoms they are experiencing are related to something that happened much earlier in their lives. This allows the disease to further progress, which is one reason most patients’ mesothelioma prognosis is very grim. Even a short period of asbestos exposure (as little as a few months) can create the conditions for a disease that erupts much later in life.

Mesothelioma affects the lining of various cavities in the body. Over time, the growth of cancerous tumors causes these tissues to expand and gather fluid. The presence of excess fluid is typically what causes the symptoms to occur. Mesothelioma symptoms also depend on the location of the tumors.

Common signs and symptoms of Mesothelioma include:

* A cough that does not go away

* Chest pain, often aggravated by deep breathing

* Hoarseness

* Weight loss and loss of appetite

* Bloody or rust-colored sputum (spit or phlegm)

* Shortness of breath

* Fever without a known reason

* Recurring infections such as bronchitis and pneumonia

* New onset of wheezing

* When Mesothelioma spreads to distant organs, it may cause:

* Bone pain

* Neurologic changes (such as weakness or numbness of a limb, dizziness)

* Jaundice (yellow coloring of the skin and eyes)

* Masses near the surface of the body, due to cancer spreading to the skin or to lymph nodes (collection of immune system cells) in the neck or above the collarbone.

A. Pleural Mesothelioma Symptoms

Some of the symptoms of pleural mesothelioma (mesothelioma cancer of the lung lining) include:

pain in the lower back or the side of the chest

shortness of breath

a persistent cough

difficulty swallowing food

fever and sweating

fatigue

weight loss.

These symptoms are also common to many minor ailments and, therefore, may not cause a doctor to suspect mesothelioma.

Pleural Effusion-fluid in the Lungs

One of the most common and specific symptoms of pleural mesothelioma is the accumulation of fluid between the lungs and chest cavity. This generally causes shortness of breath, and requires a doctor to drain the fluid, called fine-needle aspiration, to make breathing easier and relieve chest pain. This symptom is more unique to mesothelioma, making it more likely that you may have the disease.

B. Peritoneal Mesothelioma Symptoms

Symptoms of peritoneal mesothelioma (abdominal mesothelioma - mesothelioma of the lining of the stomach) include:

stomach pain

nausea and vomiting

weight loss.

Like pleural mesothelioma, these symptoms are also common to many minor ailments and, therefore, may not cause a doctor to suspect mesothelioma.

Staging systems for mesothelioma

Butchart System – extent of primary tumor mass

* Stage I: Mesothelioma is present in the right or left pleura and may also involve the diaphragm on the same side.

* Stage II: Mesothelioma invades the chest wall or involves the esophagus, heart, or pleura on both sides. Lymph nodes in the chest may also be involved.

* Stage III: Mesothelioma has penetrated through the diaphragm into the lining of the abdominal cavity or peritoneum. Lymph nodes beyond those in the chest may also be involved.

* Stage IV: There is evidence of metastasis or spread through the bloodstream to other organs.

TNM System -- variables of T (tumor), N (lymph nodes), M (metastasis)

* Stage I: Mesothelioma involves right or left pleura and may also have spread to the lung, pericardium, or diaphragm on the same side. Lymph nodes are not involved.

* Stage II: Mesothelioma has spread from the pleura on one side to nearby lymph nodes next to the lung on the same side. It may also have spread into the lung, pericardium, or diaphragm on the same side.

* Stage III: Mesothelioma is now in the chest wall, muscle, ribs, heart, esophagus, or other organs in the chest on the same side with or without spread to lymph nodes on the same side as the primary tumor.

* Stage IV: Mesothelioma has spread into the lymph nodes in the chest on the side opposite the primary tumor, or extends to the pleura or lung on the opposite side, or directly extends into organs in the abdominal cavity or neck. Any distant metastases is included in this stage.

Brigham System: (variables of tumor resectability and nodal status)

* Stage I: Resectable mesothelioma and no lymph node involvement

* Stage II: Resectable mesothelioma but with lymph node involvement

* Stage III: Unresectable mesothelioma extending into chest wall, heart, or through diaphragm, peritoneum; with or without extrathoracic lymph node involvement

* Stage IV: Distant metastatic disease.

Mesothelioma staging

Once you have been diagnosed with mesothelioma, your doctor will want to learn the extent of the disease and whether the cancer has spread to various parts of the body or to the lymph notes. Finding out this information is called staging. Knowing the phase or stage of mesothelioma will help your doctor plan treatment. For example, mesothelioma patients in early stages of the disease may be eligible for surgery. Once the mesothelioma is more advanced, pain reduction or palliative treatment may be the best course of action Generally, mesothelioma is considered localized if the cancer is found only on the membrane surface where it originated. It is classified as advanced if it has spread beyond the original membrane surface to other parts of the body, such as the lymph nodes, lungs, chest wall, or abdominal organs.There is no standard staging system for peritoneal mesothelioma. There are two staging systems for pleural mesothelioma—the TNM system, which is concerned with tumor size, lymph node analysis, and how far the tumor has spread (metastasis), and the older Butchart system, based on the extent of the primary tumor. Most cancer centers are using the TNM system in preference to the Butchart system of staging.

Some elements common to most staging systems are:

• Location of the primary tumor.
• Size and number of the tumors.
• Lymph node involvement.
• Cell type and tumor grade
• metastasis.

Many cancer registries, such as the National Cancer Institute's Surveillance, Epidemiology, and End Results Program (SEER) use summary staging, a system used for all types of cancer. Summary staging groups cancer into five main categories:

• In situ - cancer that is present only in the layer of cells in which it began.
• Localized - cancer that is limited to the organ in which it began with no evidence of spread.
• Regional - cancer that has spread from the primary site to nearby lymph nodes or organs.
• Distant - cancer that has spread from the primary site to distant lymph nodes or organs.
• Unknown - cases where not enough information exists to indicate stage.

Several types of testing may be used to help doctors determine stage, and to formulate a treatment plan.

• Physical examinations. The doctor examines the body by looking, feeling and listening to anything out of the ordinary.
• Imaging techniques. Procedures such as x-rays, CT scans, MRIs and PET scans may show the location, size of the tumor and whether the cancer has spread.
• Laboratory tests. Studies of blood, urine, fluid and tissue can provide information about the cancer. Tumor markers, sometime elevated when cancer is present, may provide information.
• Pathology reports. Results of the examination of tissue samples can include information about the size of the tumor(s), extension into adjacent structures, type of cells and grade of the tumor. Results of the examination of cells in fluid, such as that from a mesothelioma-related pleural effusion, may also provide information.
• Surgical reports. Observations about the size and appearance of the tumor(s), lymph nodes and nearby organs.

Staging information should be provided to the patient by his doctor so that potential treatment plans can be discussed. Stage of the mesothelioma, as well as consideration of other factors such as age, health status and the patient's wishes may dictate different treatment options.

The oldest staging system and the one most often used is the Butchart System which is based mainly on the extent of primary tumor mass and divides mesotheliomas into four stages. The more recent TNM system considers variables of tumor in mass and spread, lymph node involvement, and metastasis. The Brigham System is the latest system and stages mesothelioma according to resectability (the ability to surgically remove) and lymph node involvement.

Mesothelioma prognosis

Pleural mesothelioma is a difficult cancer to treat because it can spread so extensively and it is generally not diagnosed until it is in the more advanced stages, making surgical removal of all the cancer difficult or impossible. Because it is a relatively rare cancer, mesothelioma has not been studied as much as more common forms of cancer. The stage at which treatment for mesothelioma is begun has a tremendous impact on the patient’s prospects for long-term survival.

The patient’s overall health status and age affect the prognosis. The American Cancer Society reports that 75 percent of those diagnosed with mesothelioma are 65 years old or older. Men are five times more likely to have mesothelioma than women are.

When mesothelioma is diagnosed, the doctors look at how far the cancer has spread and several health factors. Pleural mesothelioma patients have a poorer prognosis if they are experiencing chest pain, shortness of breath, inability to perform daily tasks, weight loss, a low red blood cell count, a high white blood cell count, and high blood levels of a substance called LDH. According to the American Cancer Society, most mesothelioma patients who have all these factors present pass away within six months of their diagnosis. It is rare for these seriously ill patients to live two years after their diagnosis. Patients without these serious risk factors at the time of their diagnosis have a better outcome.

Mesothelioma Diagnosis

Mesothelioma can be a very difficult disease to diagnose. Many of the symptoms present as being similar to viral or bacterial diseases like pneumonia or bronchitis, and the diagnosis is further complicated by the fact that many mesothelioma patients also develop these lung conditions as a result of their illness and its weakening of their immune system. It is critically important that physicians understand whether a patient has had a significant asbestos exposure history; without that knowledge, a clinician is likely to assume that mesothelioma symptoms are caused by a much more common condition.

The diagnostic process usually begins with a complete physical examination, lung function tests, and an X-ray of the chest or abdomen. CT scans and MRIs are also often done at this stage so that the physician can get an idea of the condition of the lungs or abdomen and detect effusions (pools of liquid within the pleural sac or the abdominal cavity) which are often present in the case of mesothelioma.

The diagnosis of mesothelioma will entail scans and biopsies arranged by your doctor. A CT or MRI scan is often used to detect the possible presence of the disease, and if there is a positive indication of the presence of mesothelioma, the scans are followed up by a biopsy. Doctors often run an examination on the fluid surrounding the lungs, but all too often this is inadequate to make a firm diagnosis. In these circumstances the doctor may perform a small operation in order to remove a tissue sample and run a biopsy on that. This is known as open pleural biopsy. If you are suspected of suffering from peritoneal mesothelioma the biopsy will be performed on tissue taken from the abdominal area, known as a peritoneal biopsy.

Examination of the tissues removed by a pathologist is usually sufficient to permit the diagnosis of malignant mesothelioma, and to distinguish mesothelioma from other similar conditions such as adenocarcinoma. Patients typically do not seek medical care for mesothelioma until the symptoms have been ongoing for four to six months; this lateness of diagnosis is one of the reasons that mesothelioma has such a high mortality rate.

ou have worked with or had contact with asbestos at any time in your life, it is important that you let your doctor know. The difficulty in diagnosing mesothelioma means that you doctor may put your symptoms down to any number of diseases before testing for mesothelioma. However, if you have already made it known that you have worked with asbestos, it will give the doctor a head start in making a diagnosis. This means that test can be carried out far earlier and the necessary treatment can be prescribed.

Pericardial mesothelioma

Pericardial mesothelioma develops in the pericardium, a membrane made up of mesothelial cells that surrounds the heart and provides protection and support to this organ. The membrane is composed of two different layers: an outer layer called the parietal layer (called the heart sac or theca cordis), and an inner layer known as the visceral layer (called the epicardium). The parietal layer is part of a larger membrane that lines the entire chest cavity, while the visceral layer is the pericardial membrane that lines the heart.

The pericardium is wrapped around the heart and the origin points of all the body’s major veins and arteries. The pericardium keeps the heart in place, stops it from expanding when it is under pressure, and provides lubrication for the heart’s beating motion. There are two layers to the pericardium, the visceral layer and the parietal layer. The visceral layer is inside, next to the heart, while the parietal layer is outside. Between the two layers is a fluid layer, called pericardial fluid. The parietal layer is tougher and stronger than the visceral layer; the two layers and the liquid insulating layer provide protection for the heart from damage to the chest.

Relatively little is known about pericardial mesothelioma because it is a fairly rare form of the disease; nearly all mesothelioma sufferers have pleural or peritoneal mesothelioma.

It is established that asbestos exposure is the primary cause for pericardial mesothelioma, however; what is not known is exactly how the asbestos reaches the heart. One possibility is that the smallest asbestos fibers might enter the bloodstream from the lungs, and be thus carried into the heart cavity.

Prognosis for those with pericardial mesothelioma is grim and palliative treatment is usually the only option for people diagnosed with pericardial mesothelioma. This type of treatment is performed to improve a patient's quality of life, and reduce the severity of symptoms caused by the build-up of fluid in the pericardium. Fine needle aspiration may be carried out to remove excess fluid as well. In some cases, radiation therapy may be an option. Unfortunately, the proximity of the heart and lungs make this a risky prospect.

Peritoneal mesothelioma

Peritoneal mesothelioma is a malignant mesothelioma that forms in the peritoneum, the portion of the mesothelium that surrounds the stomach and the intestines in the abdominal cavity.

Mesothelioma of the abdomen, like all types of mesothelioma, is caused by asbestos exposure. Though it can take many years for a patient to demonstrate symptoms of peritoneal mesothelioma, the cancer develops when the asbestos fibers become lodged in the spaces between the mesothelial cells.The principal question is how the asbestos fibers are getting into the peritoneum, since it is not connected directly to the lungs.

Some researchers believe that peritoneal mesothelioma is caused when asbestos fibers are ingested in water or (more rarely) food, and then migrate through the stomach or intestinal wall. Other researchers believe that the asbestos fibers must be coming in through the lungs and then migrating into the peritoneum via the lymph system or the bloodstream. It is even possible that asbestos fibers might be present in sputum which is coughed up and then ingested.

A patient with peritoneal mesothelioma may not demonstrate symptoms of the cancer for 20 to 50 years after initial asbestos exposure since it often takes years for mesothelioma to manifest. In the case of peritoneal mesothelioma, asbestos fibers travel into the peritoneal layers where they cause irritation and inflammation and the development of cancerous cells which divide and grow uncontrollably. The cells cause thickening of the peritoneum and fluid build-up in the peritoneal layers. As the cancerous cells continue to divide overtime, tumors start to form. Most peritoneal mesothelioma symptoms are caused by this membrane thickening, fluid build-up, and eventual tumor development, all of which put pressure on internal organs.

There is an extremely rare form of peritoneal mesothelioma in which the testicles of a male patient develop tumors. The covering of the scrotum is actually an outgrowth of the peritoneal mesothelium. It is believed that fibers from the stomach may migrate to the scrotal covering and that a typical mesothelioma can form there. This is exceptionally rare, however.

Pleural mesothelioma

Pleural mesothelioma is a malignant mesothelioma that forms in the pleura, the portion of the mesothelium that surrounds the lungs in the thoracic cavity. About 75 percent of all mesothelioma cases are pleural. Pleural mesothelioma is almost always contracted when the patient inhales asbestos fibres in large numbers, often over an extended period of time. The fibers migrate into the lungs, where they become ensconced in the lung tissue. Some of the fibers move further, penetrating the lung tissue and entering the pleura.

The majority of pleural mesothelioma cases involve the right lung. Medical researchers believe that this is because the right lung is usually larger than the left lung, and has more surface area for the fibers to penetrate. For similar mechanical reasons, most pleural mesotheliomas begin in the bottom lobe of the lung rather than the top lobe, because gravity pulls the fibers down once they have been inhaled.

At first the tumors are small – little more than bumps on the pleural tissue. However, the tumors grow together quickly and form a thin lining that adds to the thickness of the pleural sac. As time passes, the lining gets thicker and thicker as more cancerous cells develop, and the newly thickened lining begins pressing on the lungs, compressing them and compromising their ability to function. This is the point at which the patient generally begins to notice symptoms. At the same time as the pleural lining is thickening, the pleural tissue begins to secrete large quantities of fluid into the pleural area, adding still further to the pressure on the lungs. Breathing becomes painful and difficult.

The tumor now begins to form what appears to be a hard shell over the pleura, and starts expanding outward into the body.The tumor mass begins to shed cancer cells, which serve as tiny ambassadors of the disease to the rest of the body.The full-blown cancer begins to metastasize – and at this point it has become almost impossible to treat.

Types of mesothelioma

Mesothelioma is caused by long-term, repeated exposure to asbestos fibers. The disease is generally found in four different forms: pleural, peritoneal, pericardial, and testicular. In each case, the cancer develops in mesothelial cells, which form the membranous linings that surround and protect organs. The different names for each type of mesothelioma refer to the point of origin of the cancer.

Mesothelioma can attack the pleural lining around the lungs. It can also attack the peritoneum, a tissue that surrounds the GI tract. Mesothelioma can attack the stomach lining, other internal organs, or even the pericardium (the tissue sac covering the heart). Thus, mesothelioma can be generally classified into the following types:

• Pleural — 75% of all mesothelioma cases
• Peritoneal — 10%–20%
• Pericardial — 5%

Mesothelioma can also be classified by the cancer type rather than the location of the cancer:

• Epithelioid — most common, best survival rate
• Sarcomatoid — most severe, but more rare
• Mixed/biphasic — a mixture of epithelioid and sarcomatoid cancer

Malignant mesothelioma

Mesothelioma (cancer of the mesothelium) is a rare form of cancer. Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles. It is known that family members of workers exposed to asbestos can contract this disease through exposure to the worker’s clothing. The combination of smoking and asbestos exposure significantly increases a person's risk of developing cancer of the air passageways in the lung.

This disease is very difficult to assess consistently due to the great variability in time before diagnosis and the rate of progression of malignant mesothelioma. The cancer keep growing until it is treated so it is very important that disease is diagnosed an treated as early as possible Mesothelioma occurs more often in men than in women and risk increase with age, but this disease can appear in either men or women at any age. Most cases of mesothelioma occur 30-45 years after initial exposure to asbestos.

Mesothelioma is a type of cancer that can be malignant or benign, the malignant type is very dangerous type and may be deadly in most cases. Scientists can classify the types of mesothelioma cancer according to the place of the tumors as following.

Pleural type, in this type the tumors will be developed in Pleura. The Pleura is the most outer membrane surrounds the lungs and has protections functions. Pleural type is the most famous type and the most cases are diagnosed as Pleural mesothelioma.

Peritoneal type, in this case the tumors will be developed in the Peritoneum. The Peritoneum is the outer membrane that surrounds the internal organs of the abdomen and has protection and movement functions. It is less common type but it is more dangerous that the Pleural type.

Pericardial type, in this case the tumors will be developed in the Pericardium. The pericardium is the outer sac that includes the heart and its great arteries. Pericardium is a protective systems for our hearts and the mesothelioma cancer in that systems is very deadly.

Asbestos effects

1. When asbestos fibers are inhaled, most fibers are expelled, but some can become lodged in the lungs and remain there throughout life. Fibers can accumulate and cause scarring and inflammation. Enough scarring and inflammation can affect breathing, leading to disease.

2. People are more likely to experience asbestos-related disorders when they are exposed to high concentrations of asbestos, are exposed for longer periods of time, and/or are exposed more often.

3. Inhaling longer, more durable asbestos fibers (such as tremolite and other amphiboles) contributes to the severity of asbestos-related disorders.

4. Exposure to asbestos, including tremolite, can increase the likelihood of lung cancer, mesothelioma, and non-malignant lung conditions such as asbestosis (restricted use of the lungs due to retained asbestos fibers) and changes in the lung lining.

5. Changes in the lining of the lungs (pleura) such as thickening, plaques, calcification, and fluid around the lungs (pleural effusion) may be early signs of asbestos exposure. These changes can affect breathing more than previously thought. Pleural effusion can be an early warning sign for mesothelioma (cancer of the lining of the lungs).

6. Most cases of asbestosis or lung cancer in workers occurred 15 years or more after the person was first exposed to asbestos.

7. Most cases of mesothelioma are diagnosed 30 years or more after the first exposure to asbestos.

8. Mesothelioma has been diagnosed in asbestos workers, family members, and residents who live close to asbestos mines.

9. Health effects from asbestos exposure may continue to progress even after exposure is stopped.

10. Smoking or cigarette smoke, together with exposure to asbestos, greatly increases the likelihood of lung cancer.

Signs and Symptoms of asbestosis can include:

Shortness of breath which is the primary symptom

A persistent and productive cough (a cough that expels mucus)

Chest tightness

Chest pain Loss of appetite

A dry, crackling sound in the lungs while inhaling.

If you suspect that you have been exposed to asbestos, speak with your physician immediately and discuss your level of exposure. Early detection of mesothelioma increases your chances immeasurably.

Asbestos exposure

Asbestos is an incredibly deadly substance; major exposure to asbestos leads to diseases such asbestosis, lung cancer, and mesothelioma, often with fatal effects. Asbestos was one of the most common industrial materials put to use in the twentieth century. The most common way for asbestos fibres to enter the body is through breathing. In fact, asbestos containing material is not generally considered to be harmful unless it is releasing dust or fibres into the air where they can be inhaled or ingested. Many of the fibres will become trapped in the mucous membranes of the nose and throat where they can then be removed, but some may pass deep into the lungs or, if swallowed, into the digestive tract. Once they are trapped in the body, the fibres can cause health problems.

It is not possible to completely avoid asbestos exposure. This is because asbestos is a naturally-occurring mineral product; it is part of the rocks that make up our planet, and as those rocks erode due to weather, fibers are released into the atmosphere. Asbestos fibers float in the air and water quite naturally, even without any human intervention or industrial development. It is estimated that a cubic meter of outdoor air (about what an adult would breathe in an hour) contains ten asbestos fibers. And – despite the deadliness of asbestos in general – this level of exposure does not present any significant health risk.

Asbestos exposure has two main pathways:

The first pathway is inhalation – drawing the fibers into the lungs because the fibers are in the air.

The second pathway is ingestion, swallowing asbestos fibers that have contaminated food or water. Asbestos fibers are not soluble in water, and so when asbestos washes into a water source by erosion from nearby rocks, runoff from mines, or asbestos-containing pipes or filters, the fibers can be absorbed by people who drink the water.

Asbestos

Asbestos is the generic term for a group of naturally occurring, fibrous minerals with high tensile strength, flexibility, and resistance to heat, chemicals, and electricity. The three most common types of asbestos are: a) chrysotile, b) amosite and c) crocidolite. Chrysotile, also known as white asbestos and a member of the Serpentine mineral group is the commonest. Asbestos can only be identified under a microscope. Asbestos differs from other minerals in its crystal development. The crystal formation of asbestos is in the form of long thin fibers. Asbestos is divided into two mineral groups:

 Serpentine and Amphibole. The division between the two types of asbestos is based upon the crystalline structure. Serpentines have a sheet or layered structure where amphiboles have a chain-like structure. As the only member of the serpentine group, Chrysotile( A, B) is the most common type of asbestos found in buildings. Chrysotile makes up approximately 90%-95% of all asbestos contained in buildings in the United States.

Asbestos was a popular component in commercial products from the early 1900’s to the 1970’s and is found in building construction materials such as:

sprayed-on fireproofing
sprayed-on or textured ceiling material
pipe and boiler insulation
floor tiles and associated mastics
cement pipe and sheeting
roofing felts and shingles
ceiling tiles
drywall and joint compounds
acoustical products.
In the amphibole group, there are five types of asbestos. As an acronym for the Asbestos Mines of South Africa, Amosite is the second most prevalent type of asbestos found in building materials. Amosite is also known as "brown asbestos." Next, there is Crocidolite or "blue asbestos," which is an asbestos found in specialized high temperature applications. The other three types (Anthophyllite, Tremolite, and Actinolite) are rare and found mainly as contaminants in other minerals. Asbestos deposits can be found throughout the world and are still mined in Australia, Canada, South Africa, and the former Soviet Union.

Mesothelium

A layer of flattened cells. Mesothelium is like a simple squamous epithelium in appearance and is derived from the mesoderm. It lines the coelomic cavities of vertebrates, including the pericardium, pleura, and peritoneum, and some other spaces, such as the synovial sacs.

Mesothelial cells form a monolayer of specialised pavement-like cells that line the body's serous cavities and internal organs. The primary function of this layer, termed the mesothelium, is to provide a slippery, non-adhesive and protective surface. However, mesothelial cells play other pivotal roles involving transport of fluid and cells across the serosal cavities, antigen presentation, inflammation and tissue repair, coagulation and fibrinolysis and tumour cell adhesion. Injury to the mesothelium triggers events leading to the migration of mesothe

lial cells from the edge of the lesion towards the wound centre and desquamation of cells into the serosal fluid which attach and incorporate into the regenerating mesothelium.

If healing is impaired, fibrous serosal adhesions form between organs and the body wall which impede

vital intrathoracic and abdominal movement. Neoplastic transformation of mesothelial cells gives rise to malignant mesothelioma, an aggressive tumour predominantly of the pleura. Although closely associated with exposure to asbestos, recent studies have implicated other factors including simian virus 40 (SV40) in its pathogenesis.

Mesothelioma cause

The only recognized cause of mesothelioma is exposure to asbestos, though other factors such as smoking can make the disease more or less likely in some individuals. Industrial laborers were widely subjected to asbestos exposure on the job, as the material was widely used throughout the 20th century. Few of these workers knew they were being exposed to asbestos, however, despite the fact that many manufacturers were aware the material was hazardous. In most cases, mesothelioma symptoms will not appear in an individual exposed to asbestos until many years after the exposure has occurred. Those who believe they may have been exposed to asbestos should fill out our form to receive a free mesothelioma information packet, detailing treatment options, emerging therapies, and jobsite exposure information.

The mesothelium is a target of the toxic and carcinogenic effects of asbestos fibers. Fibers greater than 8 mu in length and less than 0.25 mu in diameter have been found to be highly tumorigenic in rodents, while shorter asbestos fibers or spherical mineral particles have not been shown to produce mesotheliomas. For investigation of early mesothelial reactions associated with the development of mesotheliomas, C57BL/6 mice were given intraperitoneal injections of 200 micrograms of short or long crocidolite asbestos fibers, toxic silica particles, or nontoxic titanium dioxide particles. At intervals between 3 hours and 21 days after a single injection, the mesothelial surface of the diaphragm was examined by stereomicroscopy, scanning electron microscopy, and autoradiography. Within 6 hours after injection of asbestos fibers, mesothelial cells in the lacunar regions of the diaphragm retracted opening stomata 10.7 +/- 2.3 mu in diameter leading to the submesothelial lymphatic plexus. Short asbestos fibers (90.6% less than or equal to 2 mu in length), silica, or titanium dioxide particles (less than or equal to 5 mu in diameter) were cleared through these stomata without provoking an inflammatory reaction or mesothelial injury. In contrast, long asbestos fibers (60.3% greater than or equal to 2 mu in length) were trapped at the lymphatic stomata in the lacunar regions on the peritoneal surface of the diaphragm. At these sites, an intense inflammatory reaction developed with accumulation of activated macrophages and a 5.5-fold increase in albumin recovered in the peritoneal lavage fluid after 3 days. As early as 12 hours after injection of long asbestos fibers, the adjacent mesothelial cells were unable to exclude trypan blue and lost their surface microvilli, developed blebs, and detached. Recovery of lactate dehydrogenase activity in the peritoneal lavage fluid was increased 5.8-fold after 3 days and returned to normal levels after 14 days. Regenerating mesothelial cells appeared at the periphery of asbestos fiber clusters 3 days after injection. Maximal incorporation of 3H-thymidine by mesothelial cells occurred after 7 days, followed by partial restoration of the mesothelial lining after 14-21 days. As late as 6 months after a single injection of crocidolite asbestos fibers, clusters of fibers remained in the lacunar regions, partially covered by mesothelium but surrounded by macrophages and regenerating mesothelial cells. The anatomic distribution and size of lymphatic stomata on the peritoneal surface of the diaphragm account for the selective accumulation of long asbestos fibers in these regions

Mesothelioma

Mesothelioma is a rare form of cancer that affects the membrane that covers and protects various internal organs of the body (mesothelium). The mesothelium is composed of two layers of specialized cells known as mesothelial cells. One layer directly surrounds an organ; the other forms a protective sac around the organ. The most common form of mesothelioma affects the membrane or sac that lines the lungs (pleura). Other common sites include the membrane lining the stomach (peritoneum) and the membrane lining the heart (pericardium).

Mesothelioma is one of the deadliest diseases known to man; the average life span of an inflicted person from the time of diagnosis until death is less than 24 months. It’s a disease that strikes approximately 3,000 United States citizens each and every year; hard working people who have labored for a lifetime to provide for their families, doing the work that keeps this country running and a great place to live. They worked in factories, at shipyards, in mines, for the US military, as engineers, as pipefitters, as steel workers, as auto mechanics, and in so many other professions. They came home to their loved ones exhausted and covered in dirt and dust; tired, but content that they had a job and were providing for their family.