Mesothelioma Cancer - Overview

Mesothelioma is a rare type of cancer that develops in the mesothelial cells that lines many organs and body cavities. The mesothelium (composed of mesothelial cells) is the membrane that lines three of the body's cavities, and depending on what cavity it lines it is given a specific name: the thoracic cavity (pleura), abdominal cavity (peritoneum), and the heart sac (pericardium).

Mesothelioma is a rare cancer that can develop in the mesothelium of the thoracic cavity in the lungs.

The mesothelium that covers the internal organs is called the visceral mesothelium, while the layer that covers the body wall is called parietal mesothelium.

Mesothelium tissue also surrounds the male internal reproductive organs and covers the internal reprductive organs in women.

Mesothelioma is an aggressive cancer of this mesothelium, in which cells of the mesothelium become abnormal and divide uncontrollably and without order. They can invade and damage nearby tissues and organs. Most cases of mesothelioma begin in the thoracic cavity (pleura) or the abdominal cavity (peritoneum).

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 more frequently in men than in women, about four times more frequent. All forms of mesothelioma, except for benign mesothelioma, are invariably fatal. The prognosis for mesothelioma is almost always poor and most studies report a median survival of less than one year, but the prognosis really depends on how early it is diagnosed and aggressively it is treated.

Causes of Mesothelioma

Mesothelioma is caused by asbestos exposure. Asbestos is a naturally-occurring fibrous substance that was widely used in the twentieth century in a number of different industries. Popular because of its durability, fire resistance, and insulating properties, it was regularly used in the manufacture of several thousand different products, up until the time that asbestos warnings were issued in the mid-1970s. It is estimated that more than 90 percent of mesothelioma cases are linked to asbestos exposure.

The exact way in which asbestos causes mesothelioma is not well understood though doctors and researchers have put forth many hypotheses. What is apparent, however, is that any length of exposure to asbestos can be hazardous and may result in the development of asbestos-related diseases later in life.

Types of Mesothelioma

There are five known types of mesothelioma. Four of these are malignant cancers, and one is a benign 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 70 percent of cases being pleural in origin.

Peritoneal Mesothelioma: This form of mesothelioma develops in the lining of the abdominal cavity, known as the peritoneal membrane. Approximately 25 percent of mesotheliomas are of this type.

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

Testicular Mesothelioma: This is the rarest type of malignant mesothelioma; to date, there have been less than 100 recorded cases. Testicular mesothelioma develops in the tunica vaginalis of the testicles.

Benign Mesothelioma: The benign form of mesothelioma most commonly develops in the pleura. This is the only form of mesothelioma for which full cure and recovery is a probable outcome, though it may be a precursor of future asbestos-related problems.

Mesothelioma Symptoms and Diagnosis

Mesothelioma is difficult to diagnose, largely due to the fact that it remains latent in the body for up to five decades and is usually not diagnosed until its late stages.

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

The most common symptoms of pleural mesothelioma are shortness of breath, chest pain, and persistent cough. However, some patients may not show any symptoms at all. A frequent sign is pleural effusion (water in the lungs).

Some symptons of peritoneal mesothelioma include weight loss, abdominal pain and swelling, and bowel obstruction. If the cancer has spread to other parts of the body, some other common symptoms may include trouble swallowing, swelling of the neck or face, blood clotting problems, anemia, and fever.

Also, diagnosis may be difficult due to the non-specific nature of most mesothelioma symptoms, which often resemble symptoms of less serious diseases.

The process of diagnosis usually begins with a compilation of the patient's full medical and work history, including any exposure to asbestos. A medical examination is performed and if a problem is suspected, one or more diagnostic tests are ordered. These typically include medical imaging tests such as x-rays, CT, and MRI scans, as well as biopsy procedures that test samples of fluid and tissue for the presence of cancer cells. Diagnostic tests are also used to determine how far the cancer has advanced, and whether it has spread to other locations in the body.

Mesothelioma Treatment

There are a variety of treatment options for mesothelioma patients including radiation, chemotherapy, and surgery.

Mesothelioma treatments can be divided into two main categories: curative treatments and palliative treatments. Curative treatments are those carried out in an attempt to remove all cancer cells and cure the disease. Palliative treatments are designed to ease pain and make a patient more comfortable.

Treatments for mesothelioma include conventional treatments such as surgery, chemotherapy, and radiation therapy, as well as experimental procedures, including immunotherapy and gene therapy.

Generally, a patient with mesothelioma will receive more than one type of conventional treatment. For example, they may undergo surgery to remove the bulk of cancerous tissue, and then receive chemotherapy or radiation therapy to kill any remaining cancer cells.

Experimental treatments are typically available only to patients who agree to enter clinical trials. In these cases, patients must fit certain criteria to be eligible.

Legal Issues

The dangers of asbestos exposure were known long before any efforts were made to protect workers. Thousands of American workers were exposed to asbestos during the twentieth century, with no indication as to the risks that they were facing.

Companies that produced asbestos-containing products or used these products on a daily basis are liable for their negligence in failing to protect their workers. If you or a loved one has developed mesothelioma or another asbestos-related disease as a result of asbestos exposure, it's important to know you can talk to an attorney about seeking compensation for pain and suffering as well as reimbursement for medical expenses and lost income. For more information, please fill out the form on the right to receive a comprehensive packet.

Mesothelioma Cancer & Fire Fighters

Because so many buildings contain asbestos, firefighters hold a higher risk than the average person of being exposed to asbestos. Many of the buildings and structures that firefighters enter contain asbestos-containing materials or products that can release microscopic asbestos fibers into the surrounding air. Even materials found in wall insulation, ceiling & floor tiles, or pipe coverings can eventually become frayed or damaged, causing these fibers to be released. Once these asbestos fibers are released they can easily lodge themselves within a number of the body's organs including the lungs, stomach, and testicles.

Once a firefighter has inhaled asbestos he or she is at risk for developing mesothelioma cancer. A firefighter may go 20-25 years without developing mesothelioma symptoms and then suddenly become very ill without notice. Depending on the type of mesothelioma cancer the firefighter develops the symptoms can be different, however most of them include persistent dry or raspy cough, coughing up blood, difficulty swallowing, and shortness of breath. If a firefighter thinks they may have been exposed to asbestos or is experiencing these symptoms.it is very important for them to see their physician and have them perform a regular CT Scan or X-ray to make sure they haven't inhaled any asbestos fibers.

Sources:

1. Castleman, B. Asbestos: Medical and Legal Aspects. Aspen Publishers: New York. 2005.
2. Dodson, R. and Hammar, S. Asbestos: Risk Assessment, Epidemiology, and Health Effects. Taylor & Francis: Boca Raton. 2006.
3. http://www.mayoclinic.com/print/mesothelioma/DS00779/DSECTION=all&METHOD=print
4. http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_How_is_malignant _mesothelioma_diagnosed_29.asp?sitearea
5. http://www.cancer.org/docroot/CRI/content/CRI_2_4_1X_What_are_the_key_statistics_for_malignant _mesothelioma_29.asp?sitearea
6. http://www.cancer.org/downloads/PUB/DOCS/SECTION28/89.pdf
7. http://www.marf.org/Resources/UnderstandingMeso/MesoDetails.html
8. http://sup.ultrakohl.com/Uscap/uscap05/meso3.htm
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Gene Therapy

Gene therapy involves using genetic material to specifically target cancer cells and make them more vulnerable to chemotherapy treatment.

"Suicide Gene Therapy" is the most popular form of gene thearpy being used.

The main type of gene therapy being developed for use in mesothelioma patients is called "suicide gene therapy," because it forces cancer cells to produce substances that cause their death.

When undergoing this type of gene therapy, the patient is treated with a non-infectious virus that has been altered with genetic material that makes them produce a particular protein.

Following this procedure, the patient is then treated with a chemotherapeutic medication that is specially formulated to be toxic only to cancer cells. This type of therapy has produced some promising results for mesothelioma patients, but it is still only available through clinical trials.

Immunotherapy is a type of treatment in which the patient's own immune system is 'tricked' into killing cancer cells. A healthy, normally-functioning immune system does not kill cancer cells, because even though these are diseased cells, the immune system is unable to recognize them as being harmful.

There are two main types of immunotherapy: active and passive. In active immunotherapy, mesothelioma cancer cells are removed from a patient and then treated in a laboratory to turn them into a vaccine. Following this laboratory treatment, the patient is injected with the vaccine and if the treatment is successful, the patient's immune system recognizes the vaccine as a harmful substance, thus recognizing the cancer as being harmful as well.

Passive immunotherapy is somewhat different in that it does not attempt to activate the patient's immune system. Instead, it uses substances such as cytokines (molecules that direct and regulate the immune system) and other agents to help boost the patient's immune response to their cancer.

Sources:

1. Dodson, R. and Hammar, S. Asbestos: Risk Assessment, Epidemiology, and Health Effects. Taylor & Francis: Boca Raton. 2006.
2. Galateau-Salle, Francoise. Pathology of Malignant Mesothelioma. Springer-Verlag London Limited: London. 2006.
3. Pass, I., Vogelzang, N., Carbone, M. Malignant Mesothelioma: Advances in Pathogenesis, Diagnosis, and Transitional Therapies. Springer: New York. 2005.
4. http://www.cancer.org/downloads/PUB/DOCS/SECTION28/89.pdf
5. http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml
6. http://marf.org/Documents/SymSlides/Steven%20Albelda,%20MD%20WM.pdf
7. http://www.cancer.gov/cancertopics/factsheet/Therapy/photodynamic
8. http://www.drugs.com/mtm/gemcitabine.html
9. http://www.drugs.com/mtm/navelbine.html

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Photodynamic Therapy

Photodynamic therapy is a highly specialized and specific form of treatment that is most often used to treat skin cancers, some types of lung cancer, and pleural mesothelioma.

Photodynamic therapy uses light energy to kill cancer cells.

However, this treatment is usually unsuitable for patients with metastasized cancer; it is most effective in patients who have localized disease.

This type of therapy involves the use of light energy to kill cancer cells. In photodynamic therapy treatment, the patient is given an intravenous solution of a medication that makes cancer cells highly sensitive to a particular kind of light.

One to three days after this treatment, the patient is exposed to the light, and cancer cells that have absorbed the medication are killed.

Radiation

Radiation therapy, or "ionizing radiation", is used to kill cancer cells and to limit the spread of cancer. For patients with mesothelioma, radiation therapy is most often used in conjunction with surgery.

Radiation is often used in conjunction with surgery.

However, in some cases radiation may be used as a stand-alone treatment to relieve pain and other symptoms associated with mesothelioma. In either case, it is rare for radiation therapy to provide more than short-term symptomatic relief.

Mesothelioma patients may receive one of two types of radiation therapies, depending on whether or not they are suitable candidates for either procedure.

External beam radiation therapy is the traditional type of radiation therapy, where tumors are bombarded with beams of radiation to kill cancer cells. Brachytherapy is a newer type of radiation treatment. It involves tiny radioactive rods which are implanted within a tumor to provide a strong, concentrated dose of radiation to tumors while doing very little damage to surrounding healthy tissue.