About Mesothelioma

Mesothelioma is a rare form of cancer that develops in the mesothelial cells. These cells are tissue that surround or line the lungs, heart, and stomach. The mesothelial cells protect these organs by producing a lubricating fluid that allows these organs to move smoothly.

Malignant mesotheliomas arise from the cells that line the surface of the pleura or the peritoneum. Eighty percent of these tumors are pleural in origin. Malignant mesotheliomas are rare, with an incidence of one to three cases per 1 million persons per year in the general population. Approximately 2000 new cases are diagnosed each year.

The relationship between asbestos exposure and malignant mesothelioma was established in 1960. The latency period between exposure and tumor development has usually been 30 years or more.

The incidence of malignant mesothelioma has been highest in persons with heavy occupational exposure to asbestos, such as shipyard workers. However, malignant mesothelioma can occur in the absence of any known asbestos exposure. No history of such exposure has been noted in about one-third of cases, and the etiology of these cases is usually unknown. Some cases of mesothelioma have been diagnosed in family members of asbestos workers and people who reside near asbestos mines. Cigarette smoking is not considered a risk factor for malignant mesothelioma.

The patient with malignant mesothelioma of the pleura may have symptoms of dyspnea (shortness of breath)and pleuritic chest pain (pain with breathing), with malaise and weight loss. A large pleural effusion is often seen on the radiograph. This effusion which is a collection of fluid between the lungs and the chest is frequently bloody, and the hyaluronic acid level may be elevated. Associated parenchymal fibrosis (asbestosis) is rare in pleural mesothelioma but appears to be more common in peritoneal mesothelioma.

Malignant mesothelioma can be very difficult to diagnose, although medical advances have made it somewhat easier. A CAT scan or an MRI scan may show the cancer; If the cancer is in the chest, a surgeon can make a small incision between two ribs and insert a tiny instrument with a light and a camera inside, and take samples with this instrument. If the cancer is in the abdomen, a similar procedure, called a peritoneoscopy can be performed. Actual open biopsy is only necessary if there is no other way to obtain tissue,

There is no 100% effective treatment for malignant mesothelioma. Complete surgical resection is not possible in most cases. In many cases, part of the pleura and part of the tumor can be removed, surgery which decreases symptoms. The tumor encases the lung in a bulky, lobulated mass that invades the fissures and, eventually, the diaphragm and the chest wall. Average survival is one to two years. Except in rare cases, chemotherapy and radiation therapy have not been useful. Despite these facts however, there have been patients who have lived longer because of emerging treatments, and earlier diagnosis.

Anna L. Kaplan, M.D.

Type of Pleural Effusion Important for Mesothelioma Diagnosis

by Nancy Meredith
Pleural effusions are found in 95% of all pleural mesothelioma cases. When a patient presents to a doctor with pleural effusion, however, there are many other diseases which could cause the fluid buildup. There are multiple medical tests that should be conducted by the physician to determine the cause, but when exudative pleural effusion is identifed, the type associated with lung disease, a patient history to assess the possibility of asbestos exposure is important.

Pleural mesothelioma is a form of lung cancer that is almost always caused by asbestos exposure and is most commonly found in the outer lining of the lungs called the mesothelium. Due to the long latency period most cases of mesothelioma are diagnosed 30 years or more after exposure.

A pleural effusion is an accumulation of fluid between the layers of tissue that line the lungs and chest cavity. In healthy adults the body produces pleural fluid in small amounts to lubricate the surfaces of the pleura. This fluid is normally removed by lymphatics in the parietal pleura, which have the capacity to absorb 20 times more fluid than is normally formed. When this capacity is overwhelmed, a pleural effusion develops.

Transudative Effusions vs Exudative Effusions
Determining the cause and type of the pleural effusion is critical in treating the underlying disease as well as determining the appropriate method to clear the fluid from the chest cavity. A lung surrounded by excess fluid for too long may collapse.

There are two types of effusions: transudative effusions and exudative effusions.

Due to elevated pressure or low protein content in the blood vessels, fluid leaks into the pleural space causing transudative effusions. Systemic factors that alter the balance of the formation and absorption of pleural fluid, such as pulmonary embolism and cirrhosis, are the root of transudative effusions. Congestive heart failure is the most common cause of transudative effusions. Other causes include constrictive pericarditis and peritoneal dialysis.

Leaky blood vessels caused by inflammation involving irritation and swelling of the pleura and alterations in local factors that influence the formation and absorption of pleural fluid result in exudative effusions. Exudative pleural effusions are associated with asbestos-related diseases such as mesothelioma and asbestosis. The effusions are often caused by other lung diseases, including lung cancer, lung infections such as tuberculosis and pneumonia, and drug reactions.

Light's Criteria
According to The Merck Manuals the path to take in diagnosing the disease causing pleural effusion includes using Light's Criteria. This set of criteria was developed by Dr. Richard Light, Pulmonary Disease Physician and Professor of Medicine at The Vanderbilt Clinic, Nashville, TN, and Director of Pulmonary Disease Program, St Thomas Hospital, Nashville.

The two effusions are differentiated by comparing chemistries in the pleural fluid to those in the blood. Light's Criteria looks at the ratio of pleural fluid protein to serum protein, the ratio of pleural fluid LDH to serum LDH, and whether the pleural fluid LDH is more than two-thirds the normal upper limit for serum. If the criteria are met then exudative effusion is assumed and additional evaluation is needed to determine the cause of the excess fluid.

Personal History
Dr. Light agrees with his colleague Gary Lee, Consultant Physician & Senior Lecturer, Osler Chest Unit, Churchill Hospital, Oxford, UK when he says that it is important to go beyond Light's Criteria and get a detailed history of the patient so the treating physician knows what to do with the exudative identification.

Since X-rays, CT scans and potentially ultrasound have all been performed leading up to confirming that the patient has pleural effusion, and further tests confirm that the effusion is exudative in nature, if the patient's history reveals exposure to asbestos the doctor may be able to move to tests to eliminate or confirm an asbestos-related disease by checking mesothelial levels.

Injury (inflammation) to the mesothelium triggers events leading to the migration of mesothelial cells from the edge of the lesion towards the wound center, causing an increase in levels. Neoplastic transformation (conversion of a tissue with a normal growth pattern into a malignant tumor) of mesothelial cells gives rise to malignant mesothelioma.

Contact a Specialist
Due to mesothelioma’s relative rarity among the general population, it is recommended that if you are diagnosed with mesothelioma that you be treated by a team of doctors and surgeons led by a mesothelioma specialist. Mesothelioma specialists are aware of the latest research and they are able to develop a more informed treatment plan than would a physician who does not specialize in the disease.

Sources:

Pleural Effusion
Definition of Pleural Effusion

Mesothelioma Drugs

A diagnosis of mesothelioma will normally be followed by several discussions with your oncologist. Such topics of discussion will cover prognosis and treatment options to battle the disease. More often than not, the course of treatment can include a variety of mesothelioma medications.

Mesothelioma & Chemotherapy

Chemotherapy medications have been used to treat cancer since the 1950s. Many of the older ones are obsolete and have been replaced by newer, more successful drugs. An oncologist will determine which chemotherapy medication is best for you. In addition to chemotherapy, surgery or radiation may also be recommended.

Chemotherapy can be administered at a hospital, doctor's office, or in a clinic setting that caters only to cancer patients. Such treatment is most commonly administered intravenously through a catheter or directly into a vein. Some chemotherapy medications come in pill or liquid form and will be swallowed under the supervision of a doctor. Others can be taken at home following the strict instructions of a medical professional.

The dosage of the medication will be determined by your doctor and may include daily treatments for a specific time. Though chemotherapy can be very helpful, it can carry a number of side effects. Some mesothelioma patients will experience none at all while others may be shouldered with several uncomfortable side effects. These include nausea, vomiting, fatigue, loss of appetite, weight loss, hair loss, bruising or bleeding, and an increased susceptibility to infection.

Chemotherapy Medications for Mesothelioma Patients

Today's most commonly used chemotherapy medication for mesothelioma is Alimta. Currently, this drug is the only FDA-approved medication specifically designed for the treatment of malignant mesothelioma when surgery is not an option. It is generally used in combination with another chemotherapy drug called cisplatin, a platinum-based drug. Together, the two have shown promise in prolonging and improving the quality of life of mesothelioma patients. Other chemotherapy drugs sometimes used for mesothelioma treatment include carboplatin, onconase, gemcitabine, and navelbine.

Other Medications for Mesothelioma Patients

Most mesothelioma patients' drug regimens are not limited to chemotherapy medications. It is often necessary to take other medications to help combat the symptoms and side effects of the disease. Those who take the time to find the right combination of pain medications indicate a marked difference in their quality of life. However, patients should never take pain medications without consulting their doctor. In some cases, doctors will also recommend the use of anti-nausea drugs for chemotherapy patients. Anti-nausea drugs for nausea include Compazine, Torecan, Zofran and Kytril.

Sources:

1. http://www.drugs.com/mesothelioma.html
2. http://www.cancerhelp.org.uk/help/default.asp?page=5386

Types of Asbestos

The six recognized asbestos minerals, which are considered silicates (molecules that include silicon and oxygen), include:

• Chrysotile - (Also known as white or green asbestos, from the Greek word meaning "fine, silky hair") Appears as curly, whitish fibers and constitutes 95 percent of the asbestos in use. Chrysotile is mined throughout the world, but most of the United State's chrysotile supply comes from Canada, Africa, and former USSR. Scientists believe this to be the least toxic of all asbestos forms.
• Crocidolite - (Also known as riebeckite or blue asbestos) Composed of straight fibers, most crocidolite comes from southern Africa and Australia. It is believed to be the most toxic form of all asbestos minerals.
• Amosite - (Also known as cummingtonite-grunerite or brown asbestos) The trade name "amosite" is an acronym for Asbestos Mines of South Africa, after the Amosa mines. Amosite is also straight in shape, but brittle in structure and excellent for use in heat insulation.
• Anthophyllite - This form of asbestos is brittle, white, and contains various forms of iron. It has been found to have excellent resistance to chemicals and heat.
• Tremolite - In rough form, tremolite appears white and chalky. Tremolite can also be naturally found in other mineral forms aside from asbestiform. It has been the major ingredient in industrial and commercial talc.
• Actinolite - Typically prismatic, flat in structure, and elongated. Actinolite also comes in forms other than asbestiform and has poor resistance to chemicals.

The last five amphibole (which translates to "ambiguous" in Greek) types have a slightly more complex crystal structure than chrysotile and are not used as extensively in commercial products as chrysotile. Due to their structure, amphiboles tend to stay in the lungs longer than chrysotile and are more likely to cause illness because of this factor. Some hypothesize very small contaminations of amphibole fibers within chrysotile are most to blame for cancer deaths caused by asbestos exposure.

Asbestiform minerals are found in serpentine and ultramafic rock. These rocks are located throughout the United States, especially near mountainous regions. California is exceptionally bountiful in asbestos, where the mineral can be found in at least 44 of the state's 58 counties (some geologists report asbestos is found in 50 of the 58 counties). Asbestos fibers especially form near fault zones, where temperature, pressure, and time have transformed the molecules into the asbestiform crystals.

Sources: http://www.asbestos.com/asbestos/

What is Asbestos?

The term "asbestos" has been given to six naturally occurring mineral fibers that have been used for commercial purposes. It can be found in hundreds of countries on just about every continent. These fibers belong to two separate mineral groups, known as serpentine and amphibole.

A Detailed Diagram of Where Asbestos Can Be Found in the Home

The serpentine group, usually of a curly form, contains only one asbestiform variety, referred to as chrysotile. The amphibole group, which is straight and needle-like, contains five asbestiform varieties: anthophyllite, grunerite (amosite), riebeckite (crocidolite), tremolite, and actinolite.

The U.S. Bureau of Mines has listed more than 100 mineral fibers as "asbestos-like" fibers, but the United States government only regulates the six aforementioned forms (primarily due to effective lobbying on behalf of the asbestos and stone industries).

These very fine fibers are separable, hundreds of times thinner than human hairs, and too small to be seen with the naked eye. The Occupational Safety and Health Administration (OSHA) defines fibers of concern as at least five micrometers long and at least three times as long as their diameters. For a frame of reference, mineralogists work with fibers as much as a thousand times as long as their diameters.

Sources: http://www.asbestos.com/asbestos/

Additional Risk Factors

Other risk factors that may cause malignant mesothelioma include:

• Radiation: Some mesothelioma patients with no traceable history of asbestos exposure do share a history of radiation exposure. Around 45 cases of mesothelioma following radiation therapy have been reported and discussed in medical literature.
• Nonasbestos Mineral Fibers: A few nonasbestos mineral fibers have been linked to malignant mesothelioma, such as erionite and taconite.
• Simian Virus 40: Originating in the rhesus monkey and contaminating millions of polio vaccines administered in the 1950s and ’60s, simian virus 40 has been linked to malignant mesothelioma and several other malignancies.

Additional risk factors that are not as well-researched in medical literature include chronic inflammation, chest injuries, genetics and organic chemicals.

It should be noted that cancer doctors and research scientists know that smoking does not cause mesothelioma, but it can aggravate other asbestos-related conditions (such as asbestosis) and compromises the body’s ability to fight the biological effects of asbestos fibers. Additionally, asbestos exposure and smoking has a synergistic affect that can increase a person's risk of developing lung cancer by as much as 84 times or more. For this reason, those who have been exposed to asbestos are highly advised not to smoke.

For those who would like to learn more, extensive information about mesothelioma and treatment options are available to patients and their family members by filling out this form or calling 800-615-2270 and speaking with an educated patient and family advocate.

Sources:

1. Dodson, R. and Hammar, S. Asbestos: Risk Assessment, Epidemiology, and Health Effects. Taylor & Francis: Boca Raton. 2006.
2. Castleman, B. Asbestos: Medical and Legal Aspects. Aspen Publishers: New York. 2005.
3. Webster, P. White Dust Black Death. Trafford: Canada. 2005.
4. Robinson, Bruce W. S.; Musk, Arthur W.; Lake, Richard A.. Lancet, 7/30/2005, Vol. 366 Issue 9483, p397-408.
5. http://www.cancer.org/downloads/PUB/DOCS/SECTION28/89.pdf

Mesothelioma Diagnosis

A medical exam is the first step in diagnosing an asbestos-related illness.

The process of mesothelioma diagnosis usually begins with a review of a patient’s medical history followed by a physical examination.

If a problem is suspected, a doctor may request several diagnostic tests. These typically include medical imaging scans such as:

• X-rays
• CT scans
• PET scans
• MRI scans

A combination of these tests is often used to determine the location, size and type of the cancer. Biopsy procedures are often requested following an imaging scan to test samples of fluid and tissue for the presence of cancerous cells.

Sources: http://www.asbestos.com/mesothelioma/

Mesothelioma Symptoms

A patient with mesothelioma often demonstrates symptoms 15 to 50 years after initial exposure to asbestos. The cancer may take decades to develop in the body and symptoms do not arise until after the cancer is present. Many patients are unaware of the severity of their condition since mesothelioma symptoms typically resemble symptoms of less serious illnesses.

If you have a history of asbestos exposure, the leading cause of mesothelioma, it is best to seek immediate medical advice. Informing your doctor of previous asbestos exposure can alert them to the possibility of an asbestos-related disease such as mesothelioma.

Sources: http://www.asbestos.com/mesothelioma/

Mesothelioma Types

There are five known types of mesothelioma. The four listed below are malignant cancers, and benign mesothelioma is a non-cancerous condition.

Once asbestos is inhaled it can effect many of the bodys different organs including the throat, lungs, stomach, heart and testicles.

Pleural Mesothelioma: This type of mesothelioma develops in the lining of the lungs, known as the pleura. It is the most common form of malignant mesothelioma, with around 75 percent of cases being pleural in origin.

Peritoneal Mesothelioma: Comprising approximately 20 percent of mesothelioma cases, this form of mesothelioma develops in the lining of the abdominal cavity, known as the peritoneal membrane.

Pericardial Mesothelioma: This form of mesothelioma develops in the lining of the heart, known as the pericardium. Approximately 5 percent of all mesothelioma cases are pericardial.

Testicular Mesothelioma: Testicular mesothelioma develops in the tunica vaginalis of the testicles and is the rarest form of the cancer.

Sources: http://www.asbestos.com/mesothelioma/

Mesothelioma Causes

Mesothelioma is a rare cancer that can develop in the membrane that lines the lungs, called the mesothelium.

Mesothelioma is caused by asbestos exposure which occurs when fibers are inhaled or ingested into the body and become lodged in body cavities, causing inflammation or infection. Asbestos is a naturally-occurring fibrous substance that was widely used in the 20th century in a number of different industries. When the public became aware of the hazards associated with the mineral, warnings were issued in the mid-1970s and use of the product began to decline.

More than 30 percent of those diagnosed with mesothelioma are veterans. Please visit the page on asbestos for additional information about the mineral.

Material from the http://www.asbestos.com/mesothelioma/

Mesothelioma Overview

Mesothelioma

Mesothelioma is a rare type of cancer that typically affects the lining of the lungs, heart and abdomen. Approximately 2,000 to 3,000 cases of mesothelioma are diagnosed each year in the United States, comprising around 3 percent of all cancer diagnoses. This cancer occurs about four times more frequently in men than in women and all forms of mesothelioma, except for benign mesothelioma, are invariably fatal.

The life expectancy for mesothelioma patients is generally reported as less than one year following diagnosis, however a patient’s prognosis is affected by numerous factors including how early the cancer is diagnosed and how aggressively it is treated.

In an effort to help patients understand mesothelioma, Asbestos.com offers a complimentary packet that contains treatment information tailored to your specific diagnosis. The packet also covers the nation's top mesothelioma doctors and cancer centers, as well as financial assistance options to help cover medical costs. To receive your packet in the mail, please enter your information below.

Sources: http://www.asbestos.com/mesothelioma/