Table of Contents
- 1 What is a Mesothelium?
- 2 Location of Disease
- 3 Histological Subtypes
- 4 Mesothelioma and Asbestos
- 5 Tragedy of Mesothelioma
- 6 Mesothelioma Information
- 7 Progression of Mesothelioma has 4 Stages
- 8 Mesothelioma Cancer Cell Types
- 9 Mesothelioma Symptoms
- 10 Mesothelioma Treatment Options
Malignant mesothelioma is an aggressive cancer in the lining of the lungs or abdomen. The only known cause of malignant mesothelioma is asbestos exposure. When asbestos fibers are inhaled or ingested, the body is unable to break them down or expel them. Asbestos fibers invade the protective lining that surrounds many of the body’s internal organs and remain in the body, causing scarring and damaging sensitive tissues. That damage can eventually lead to malignant mesothelioma, asbestos-related lung cancer, or another asbestos disease.
If you or a loved one has been diagnosed with malignant mesothelioma, you may be entitled to financial compensation from the companies that were responsible for your asbestos exposure. Contact us today to learn about your legal options for pursuing the compensation you and your family deserve.
Causes of Mesothelioma
The only known cause of malignant mesothelioma is asbestos exposure. Asbestos is a fiber that was once widely used in hundreds of building, industrial, commercial, and housing products and is still present in millions of U.S. workplaces and homes. The risk of exposure to asbestos remains a very real danger. And symptoms of malignant mesothelioma do not appear for at least 15 years after asbestos exposure.
For those who worked with or around asbestos products, airborne fibers can be inhaled or ingested, lodging themselves in the tissue lining the lung (known as the pleura), chest cavity, or abdominal cavity. These fibers can stay in the body for decades before malignant mesothelioma develops.
There are six sub-classifications of asbestos: actinolite, amosite, anthophyllite, chrysotile, crocidolite, and tremolite. Asbestos, the commercial name given to these fibers, was a valuable material in several industries, particularly steel manufacturing and shipyards, in the early to mid-20th century. Asbestos easily separates when handled, causing microscopic particles to be released into the air and posing a danger to anyone in the vicinity. A vast majority of people diagnosed with malignant mesothelioma faced asbestos exposure on job sites.
How common is malignant mesothelioma?
- Research shows more than 20 million people in the United States are at risk of developing malignant mesothelioma due to asbestos exposure.
- More than 100,000 U.S. citizens are expected to die of mesothelioma during the next 40 years.
- 18,068 Americans died from malignant mesothelioma between 1999 and 2005. 14,591 of the deaths occurred in men.
- Today, malignant mesothelioma is responsible for approximately 3,000 deaths per year in the United States and 5,000 deaths in Western Europe. However, mortality rates are expected to increase by 5-10% per year in most industrialized countries until about 2020.
- An estimated 1.3 million construction and general industry workers potentially are being exposed to asbestos.
- The World Health Organization estimates that asbestos causes approximately half of all deaths from occupational cancer, and 125 million people worldwide are exposed to asbestos in the workplace.
Malignant mesothelioma is a relatively rare cancer. About 3,000 Americans are diagnosed with the disease each year, according to the U.S. Centers for Disease Control and Prevention. The typical latency period for mesothelioma (time between asbestos exposure and visible symptoms) can range from 15 to 60 years.
One study published in The Annals of Occupational Hygiene in 2003 analyzed 796 cases of asbestos-related disease and found that the latency period was about three years less for asbestosis versus mesothelioma. Patients with latency periods of less than 20 years were extremely rare, accounting for only 3 percent of asbestosis cases and 2 percent of mesothelioma cases.
The deadly disease of mesothelioma is diagnosed in close to 3,000 Americans each year. The only established cause of this cancer is exposure to asbestos. The real tragedy is that this fatal disease could have been avoided. Most victims were unknowingly exposed to asbestos at work or while serving in the military.
Other victims developed mesothelioma due to environmental exposure from loved ones coming home from work with their clothes covered in asbestos fibers.
This type of cancer is diffuse malignancy that spreads itself throughout a tissue area as an invasion of a large number of smaller masses, unlike other cancers that are characterized by a single, solid tumor mass.
This diffuse nature has important implications for how treatment, and complete surgical extraction of the cancer is difficult.
What is a Mesothelium?
The mesothelium, the membrane that surrounds many of the body’s vital organs, is where the cancer develops when asbestos is inhaled or ingested.
The membrane secretes a lubricating fluid that provides easy movement of the organs within the body.
When the mesothelium becomes cancerous, it is called mesothelioma.
There are multiple forms of the cancer when it affects the mesothelium. The form is determined by the location in which the tumor begins, known as its origin site, and the type of cells that the tumor invades, known as its histological subtype.
Each type may require a different treatment.
Location of Disease
The most common form, as many as eighty percent of all diagnoses, is pleural mesothelioma, where the cancer attacks the pleural tissue surrounding the lung. The pleura proximity to the lung is the reason many people mistakenly think of this form as lung cancer, which it is not.
Although the cancer can spread (“metastasize”) from the pleura into the lung, the origin site is the actual pleural tissue surrounding the lung – not the lung itself. There are many differences between mesothelioma and lung cancer.
The next most common type is peritoneal mesothelioma, which develops in the majority of other cases. While pericardial and tunica vaginalis are also possible forms of the disease, they are very rare.
Besides the location in which the tumors form, the other identifying factor in the diagnosis of mesothelioma is the histological subtype of the cancer.
This refers to the type of cells that the tumors invade.
There are three histological subtypes:
Epithelioid, which attacks epithelial cells
Sarcomatoid, which attacks sarcomatous cells, and bi-phasic, where the tumor attacks both epithelial and sarcomatous cells.
The identification of the proper subtype is an important diagnostic factor because it greatly affects the disease prognosis.
Epithelioid has the best response rate for treatment, while sarcomatoid has the worst.
Mesothelioma and Asbestos
While a rare disorder in the general population, mesothelioma is not rare among individuals exposed to asbestos. There are two to three thousand new diagnoses of the cancer every year.
Exposure to asbestos is the only confirmed cause of mesothelioma, and most people diagnosed with the disease were exposed to asbestos in the workplace and were never told of its dangers or given proper protective gear. Others were exposed through family members who brought asbestos home on their clothes or through home renovation projects.
Unlike many other predominantly pulmonary-related cancers, cigarette smoking has no known causative effect on its incidence, although asbestos workers who smoke do have a much greater likelihood to develop lung cancer, even more so than regular smokers who don’t work with asbestos.
Tragedy of Mesothelioma
The great tragedy of this deadly disease is that it was preventable. Many of the corporations that manufactured and profited from the sale of asbestos-containing products were aware of the hazards of asbestos.
These companies did not warn of the risks or protect workers.
It was their legal duty to know about their products and to test them for any potential hazards. If a potential hazard did exist, the company had a responsibility to warn workers of these hazards. In many cases they hid the knowledge they had in order to protect themselves from liability or from having to find a new business model.
The result is that many workers have unnecessarily developed mesothelioma.
Source: Global mesothelioma deaths reported to the World Health Organization be tween 1994 and 2008
Malignant mesothelioma is so-named because it affects the mesothelium (or mesothelial membrane), a layer of cells covering body cavities and internal organs. The mesothelium is composed of mesothelial cells, which provide a protective surface and play a role in a number of processes such as fluid transport, inflammation, and tissue repair. The mesothelium lines the pleural, peritoneal, and pericardial cavities, as well as the testicles. When asbestos fibers are inhaled or ingested, they can enter the mesothelium and injure the mesothelial cells, eventually giving rise to malignant tumors.
The most common type of the cancer is malignant pleural mesothelioma, which affects the pleura — the mesothelial membrane lining the lungs and chest wall. Mesothelioma that begins in the pleura typically results from asbestos fibers being inhaled. Tumors that develop in the pleura may spread to the nearby diaphragm, heart, and blood vessels of the chest. Early symptoms of malignant pleural mesothelioma can include shortness of breath, pleural effusion (fluid build-up), chest pain, cough, and a lack of energy.
When it develops in the peritoneum, the mesothelial membrane that covers the abdominal cavity and the organs within it, the cancer is called peritoneal mesothelioma (or abdominal mesothelioma). Peritoneal mesothelioma is the second most common form of this cancer, accounting for about 10 percent to 15 percent of new diagnoses. Peritoneal mesothelioma may result from swallowing asbestos fibers or inhaling fibers that then work their way into the abdomen. Patients with malignant peritoneal mesothelioma often experience abdominal swelling due to fluid build-up accompanied by abdominal pain, weight loss, and loss of appetite.
TThe pericardium is the mesothelial membrane covering the heart. Pericardial mesothelioma is a highly lethal and very rare form of the cancer, accounting for roughly 1 percent to 5 percent of all new mesothelioma cases. Fluid in the pericardial space, shortness of breath, fever, chest pain, weight loss, and heart palpitations are symptoms of pericardial mesothelioma.
The rarest of all types, mesothelioma of the tunica vaginalis testis (testicular mesothelioma) is a tumor of the membrane covering the testicle. Because of its rarity, there is little clinical agreement about testicular mesothelioma characteristics and symptoms, making diagnosis extremely difficult. Patients sometimes report painful swelling of the testicle, and a doctor diagnoses the cancer intra-operatively (during surgery) or post-operatively, following laboratory analysis. Ultrasound and other imaging tests may also be used for diagnosis.
Symptoms of malignant pleural mesothelioma, the most common form of the cancer, often start out like other respiratory diseases such as the flu, pneumonia, or COPD. However, anyone with a history of asbestos exposure should seek medical attention immediately if he or she exhibits these symptoms:
- Shortness of breath
- Chest pain
- Pleural effusion (fluid on the lungs)
- Weight loss
- Persistent cough
- Loss of appetite
Progression of Mesothelioma has 4 Stages
Traditionally, these stages measured only the tumor mass under the Butchart System. A second system, TNM system, looks at the growth of lymph nodes, which filter out harmful substances from the body, and metastasis, or the extent that the cancer has spread. Another system, called the Brigham System, focuses on surgical options and the extent that lymph nodes are affected. All staging systems relate to pleural (chest) mesothelioma, the most common form of the disease, and use four stages. There are no established staging systems for peritoneal or pericardial mesothelioma. The first two stages for Butchart and TNM are fairly similar.
Stage I: Cancer is limited to one side of the chest’s pleural lining.
The pleural lining is a wet, thin membrane between the lungs and the walls of the chest cavity. Its purpose is to protect the lungs from abrasion. There are two layers of this lining, or pleura: one that lines the lungs, and one that lines the chest wall. Under normal breathing, these linings easily slide over each other. When malignant mesothelioma develops in the lining (pleura), it thickens and can press on the lung. Fluid can accumulate between the pleura. At this point, there can be trouble breathing, chest pain, coughing, and hoarseness. The TNM staging system breaks down Stage I into two categories that describe where the cancer is located.
- Stage IA is when the cancer is found on one side of the chest in the chest wall lining. It also covers when it is found in the chest cavity lining between the lungs and/or the lining that covers the diaphragm. The cancer has not affected the lung.
- Stage IB is used when cancer is in the chest lining on one side of the chest and on the lining that covers the lung. It includes cancer in the linings of the chest cavity and/or diaphragm.
Stage II: The cancer has spread (metastasized).
However, the cancer remains in the chest or has reached above it to the esophagus.
The two systems have different definitions for Stages III and IV.
The tumor system, or Butchart System, defines Stage III as further spreading through the diaphragm to reach the lining around abdomen or lymph nodes outside the chest. Stage IV occurs when the cancer can be found in the bloodstream and has further spread to other organs.
- The TNM System defines Stage III as further spread within the same side of the chest. Stage IV is then the cancer has spread outside the one side of the chest to the other side and to other organs as well.
The Brigham System follows these stages:
- Stage I: The cancer has not spread to lymph nodes and can be surgically removed.
- Stage II: Surgery is still possible but the cancer has spread to lymph nodes.
- Stage III: Surgery is no longer possible and the cancer has spread to other parts of the chest, including the heart.
Mesothelioma Cancer Cell Types
Mesothelioma cells are grouped into three main categories: epithelioid, sarcomatoid (fibrous), and biphasic (mixed). Epithelioid mesothelioma is by far the most common, while sarcomatoid mesothelioma is the least diagnosed and most difficult to treat.
Each case is unique, and there is no one-size-fits-all treatment. The stage of the disease and the tumor’s location are the two most important factors when determining treatment options. More aggressive treatments can be applied to epithelioid cells due to a better prognosis than sarcomatoid and biphasic cases.
A second opinion is recommended for all patients diagnosed with sarcomatoid mesothelioma and biphasic mesothelioma. An accurate diagnosis is the key to getting the best and proper treatments.
Epithelioid mesothelioma is the most common type of the disease, accounting for 60 to 75 percent of all new cases. It will generally begin to show visible symptoms between ages 50 and 70, with upwards of 80 percent of new diagnoses being in men. Cancers of epithelial tissue are called carcinomas. A study published in the September 2000 respiratory medicine journal Thorax determined that epithelioid mesothelioma patients had a better prognosis than those diagnosed with sarcomatous or biphasic mesothelioma.
Sarcomatoid mesothelioma comprises only 7 to 20 percent of all new diagnoses in the U.S., making it the least common form. It is also the most aggressive and deadliest of the three histological cell types. A 2002 study of 108 sarcomatoid renal cell carcinoma patients at the University of Texas M.D. Anderson Cancer Center, found that metastasis (spreading of the cancer) was present in 77 percent of them. Sarcomatoid cells affect supportive tissue, like bones, muscles, and cartilage as opposed to the membranous tissue affected by epithelioid diagnoses.
Biphasic mesothelioma cases have physical characteristics of both epithelioid and sarcomatoid mesothelioma. The previous are continuous square-shaped malignant cells with a nucleus, while the latter are oval-shaped with no identifiable nucleus. Biphasic mesothelioma is most common in pleural patients. Approximately 20-35 percent of all mesothelioma cases are classified as biphasic, making it the second-most common type of the disease. Though both types of malignant cells are found in biphasic patients, they are usually in different areas of the tumor.
Malignant mesothelioma is known as an orphan disease in the United States. An orphan or rare disease status is assigned to a disease or disorder if it affects fewer than 200,000 Americans at any given time. The U.S. Food and Drug Administration estimates that 25 million people are affected by more than 6,000 rare diseases. According to the National Organization for Rare Disorders, 1 out of 10 Americans has a rare disease.
Malignant mesothelioma is diagnosed in 3,000 Americans each year and shares the orphan disease distinction with other well-known diseases including multiple sclerosis, AIDS, and cerebral palsy. According to government statistics, 85 percent to 90 percent of orphan diseases are serious or life-threatening, yet only about 200 of them currently have any effective treatments.
However, there is hope. The government and pharmaceutical companies are always pursuing effective treatments for rare disease sufferers through research and clinical trials. In 2012, the U.S. National Institutes of Health and the European Commission joined forces to form the International Rare Disease Research Consortium. That group is committed “to the development of 200 new rare disease treatments by the year 2020 and the development of diagnostics for all rare disorders.”
Pain As A Symptom
Over half of all pleural mesothelioma patients have pain in the lower, back or sides of the chest. Sufferers of peritoneal mesothelioma may also experience pain in the abdominal area. Pericardial mesothelioma patients often have chest pain, heart palpitations, shortness of breath, and constant and acute coughing. Mesothelioma patient pain typically increases over time and can be acute in many cases, requiring prescription narcotics to manage. It is important that patients let their physicians know about the pain they are feeling. Support from a medical team can lessen those symptoms by use of these medications:
- Mild pain is typically treated with over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) containing ibuprofen, aspirin, naproxen or acetaminophen.
- Moderate pain often involves the use of opioid medications that are sometimes used in combination with NSAIDs. Opioid products are hydrocodone, codeine, methadone or oxycodone.
- Severe pain is often experienced following surgery and is typically managed through “patient-controlled analgesia” whereby the patient can manage the dosage of the painkiller. Most often this is a morphine drip. Higher doses of the moderate pain relievers may be used or other drugs can be prescribed including fentanyl and hydromorphone.
Mesothelioma Treatment Options
Malignant mesothelioma is one of many cancers that is still considered incurable.
Treatment is difficult because the cancer is:
- Very aggressive
- Usually diagnosed in the late stages
Many treatments focus on maximizing life expectancy and decreasing the pain and symptoms associated with malignant pleural mesothelioma and other forms of the cancer. Patients may undergo surgery, chemotherapy, or radiation therapy. Mesothelioma treatments are primarily based on methods used for other cancers.
There are some rays of hope for mesothelioma sufferers — with the success of recent research and clinical trials, new treatments have been developed that specifically target malignant mesothelioma. Targeted therapies take advantage of the unique genetic characteristics of the patient, and personalized treatments allow doctors to select an approach that is most effective for each patient.