Definition- What is Mesothelioma?
Malignant mesothelioma (me-zoe-thee-lee-O-muh) is a rare but aggressive cancer affecting the thin layer of tissue that covers the majority of your internal organs (mesothelium) especially the membrane lining of the lungs and abdomen.
Malignant mesothelioma is the most serious of all asbestos-related diseases. Exposure to asbestos is the primary cause and risk factor for mesothelioma. Mesothelioma is primarily caused by exposure to asbestos, though cases have been documented in children or other individuals with no asbestos history.
What is Asbestos?
Asbestos is a microscopic and naturally-occurring mineral that lodges in the pleural lining of the lungs and the peritoneal lining of the abdominal cavity. In most cases, several years and even decades may pass before mesothelioma develops in those who have been exposed to asbestos.
The Primary Risk factor for Mesothelioma is Asbestos Exposure:
Asbestos is a mineral that's found naturally in the environment that had a wide variety of useful applications, including insulation, brakes, shingles, flooring and many other products as the asbestos fibers are strong and resistant to heat.
Asbestos dust may be created when asbestos is broken up during the mining process or when removing asbestos insulation. If the dust is inhaled or swallowed, the asbestos fibers will settle in the lungs or in the stomach. These fibers can cause irritation that may lead to mesothelioma. It can take 30 to 40 years or more for mesothelioma to develop after asbestos exposure. Not all people exposed to asbestos develop mesothelioma while others with very brief exposure develop the disease.
There are Several Possible Mesothelioma Risk Factors
Factors that may increase the risk of mesothelioma include:
Personal history of asbestos exposure. Being exposed to asbestos fibers at work or at home, including living with someone who works with asbestos. People who are exposed to asbestos may carry the fibers home on their skin and clothing, exposing the people around them.
Some research indicates a link between mesothelioma and monkey virus used in polio vaccines. The simian virus 40 (SV40), is a virus originally found in monkeys. Between 1955 and 1964, millions of people may have been exposed to SV40 when receiving polio vaccinations because the vaccine was developed using monkey cells. The virus was removed from the polio vaccine once it was discovered that SV40 was linked to certain cancers. The link is still a point of debate, and more research is needed.
Making a correct mesothelioma diagnosis is particularly difficult for doctors because the disease often presents with symptoms that mimic other common ailments.
The Three Major Types of Mesothelioma
Doctors divide mesothelioma into different types based on what part of the mesothelium is affected. Three major types of mesothelioma exist and they are differentiated by the organs primarily affected.
Pleural malignant mesothelioma: Affects the lung’s protective lining in the chest cavity. Pleural malignant mesothelioma represents about three-quarters of all mesothelioma incidence.
Peritoneal mesothelioma: Affects the tissue in abdominal cavity, heart and around the testicles.
Pericardial mesothelioma: Affects the cardiac cavity.
Mesothelioma does not include a form of noncancerous (benign) tumor that occurs in the chest and is sometimes called benign mesothelioma or solitary fibrous tumor.
The mesothelium of the chest, abdomen, and cardiac cavity are called the pleura, the peritoneum, and the pericardium, respectively. Each of these groupings of mesothelial cells is extremely critical to the functions of the body structures which they encompass.
The mesothelium is particularly important to organs that are commonly in motion, such as expansion or contraction of the lungs, stomach, or heart. Lubrication from the mesothelial cells allows free range of motion within the body.
Malignancies (cancerous tumors) occurring within the mesothelial membranes are known as malignant mesothelioma, or simply mesothelioma. Benign tumors of the
mesothelium are known to occur, but are much more rare than malignant mesothelial tumors.
While tumors of the mesothelium were first recognized in the late 18th century, it was not until the middle of the 20th century that this particular cancer was studied and examined with more detail. It was at this time when suspicions of the cancer’s causal relationship with asbestos exposure became more substantiated. A joint research venture through the Department of Thoracic Surgery at the University of the Witswater and Johannesburg General Hospital in South Africa provided the most compelling evidence of the nexus between asbestos exposure and the development of pleural mesothelioma.
How Common is Mesothelioma?
Compared to many cancers, mesothelioma is still quite rare. Only 2,500-3,000 cases are diagnosed in the United States each year. There was a sharp increase in reported mesothelioma diagnoses between 1970 and 1984 which was linked to increased industrial exposure 40-60 years prior to this time, particularly prevalent in the WWII-era military industrial cycle, including navy shipyards.
While exposure was common across the United States in nearly all industries, it is much more common in men over the age of 60. Although less common, mesothelioma in women and children has been documented as well. Mesothelioma causes for diagnosis in women and children are mainly attributed to secondary exposure to asbestos by men who worked in asbestos-related jobs to bring back into the home on their bodies or clothing.
Mesothelioma is diagnosed through a comprehensive combination of biopsy and imaging scans.
Signs and symptoms of Pleural mesothelioma, which affects the tissue that surrounds the lungs, may include:
- Unusual lumps of tissue under the skin on your chest
- Unexplained weight loss
- Chest pain under the rib cage
- Painful coughing
- Shortness of breath
Signs and symptoms of Peritoneal mesothelioma, which occurs in tissue in the abdomen, may include:
- Lumps of tissue in the abdomen
- Unexplained weight loss
- Abdominal pain
- Abdominal swelling
How is Mesothelioma Diagnosed?
Mesothelioma is often misdiagnosed. Symptoms of mesothelioma include chest pain, chronic cough, effusions of the chest and abdomen, and the presence of blood in lung fluid.
Mesothelioma can be difficult to diagnose because the symptoms of the disease closely resemble other respiratory conditions. The pathology can be very difficult to distinguish from adenocarcinoma of the lung.
Mesothelioma is diagnosed through a comprehensive combination of biopsy and imaging scans.
Diagnostic surgeries, including a biopsy, will typically be required to determine the type of malignant cells that are present in the body. Typically a body imaging scan, including an MRI, CT scan, and PET scan, will be required to determine the extent and location of the disease. A formal staging classification exists only for pleural mesothelioma because of how rare mesothelioma is.
When Should You see a Doctor?
See your doctor if you have signs and symptoms that may indicate mesothelioma and tell your doctor if you've been exposed to asbestos fibers.
Due to the rarity of mesothelioma, signs and symptoms of mesothelioma aren't specific to this disease and are more likely to be related to other conditions. If any persistent signs and symptoms seem unusual or bothersome, ask your doctor for further tests and evaluation.
Complications of Pleural Mesothelioma
As pleural mesothelioma spreads in the chest, it puts pressure on the structures in that area which can cause complications including:
- Swelling of the neck and face caused by pressure on the large vein that leads from your upper body to your heart
- Pain caused by pressure on the nerves and spinal cord
- Accumulation of fluid in the chest which can make breathing difficult
- Difficulty breathing
- Chest pain
- Difficulty swallowing
Mesothelioma is an aggressive, but manageable, malignancy. While mesothelioma is not often diagnosis until it is in its advanced stages and there is no cure at this time treatment, options are available. These treatments may include surgery, chemotherapy, and radiation therapy. There are also newer medications available.
Talk to your doctor about treatment options. Some people may choose aggressive treatment for their cancer while others prefer treatments that make them comfortable so that they can live their remaining time as symptom-free as possible. There are no right or wrong answers, only choices.
Radiation therapy is often used in conjunction with other treatment methods like surgery and chemotherapy. Radiation therapy focuses high-energy beams, such as X-rays, to a specific spot or spots on your body to reduce signs and symptoms of pleural mesothelioma. Radiation therapy is sometimes used after biopsy or surgery to prevent mesothelioma from spreading to the surgical incision.
Chemotherapy uses chemicals to kill cancer cells. Systemic chemotherapy travels throughout the body and may shrink or slow the growth of a mesothelioma that can't be removed using surgery. Chemotherapy may also be used before surgery to make an operation easier or after surgery to reduce the chance that cancer will return.
Chemotherapy drugs may also be heated and administered directly into the abdominal cavity of peritoneal mesothelioma, or into the chest cavity in the case of pleural mesothelioma.
Surgeons work to remove mesothelioma when it's diagnosed at an early stage. Sometimes it isn't possible to remove all of the cancer. In those cases, surgery may help to reduce the signs and symptoms caused by mesothelioma spreading in your body. In some cases this may cure the cancer.
Surgical options may include:
Surgery to decrease fluid buildup where a tube or catheter is inserted into the patient’s chest to drain the fluid. Doctors may also inject medicine into the patient’s chest to prevent fluid from returning.
Surgery to remove the tissue around the lungs or abdomen won’t cure mesothelioma, but may relieve signs and symptoms.
Surgery to remove as much of the cancer as possible allows doctors to more accurately direct radiation treatments to relieve pain and fluid buildup caused by mesothelioma.
Surgery to remove a lung and the surrounding tissue may relieve signs and symptoms of pleural mesothelioma. If you'll be receiving radiation therapy to the affected area after surgery, this procedure will allow the doctors to use higher doses, without the worry of protecting your lung from damaging radiation.
Medical treatment costs can be significant with a mesothelioma diagnosis. Individuals diagnosed with mesothelioma that have been known to be exposed to asbestos may be eligible for financial compensation from asbestos manufacturers for their illness to help offset those costs. Talk to your doctor, search online or consult an attorney who specializes in medical cases.
A diagnosis of mesothelioma can be devastating to the person diagnosed and for their family and friends. Some suggestions to help you cope include:
Educate yourself. Learn enough about mesothelioma to make decisions about your care. Write down questions and bring them to your doctor and treatment team. Use the internet to find information on the disease from credible sources including the National Cancer Institute and the American Cancer Society.
Find Support. Use or create a support network that can include coworkers, church members, close friends or family. These people can help you with everyday tasks including appointments and treatment. Don’t be afraid to ask for help and don’t be afraid to accept it.
Seek out other people with cancer. Look for cancer support groups in your community and online. Ask your health care team for suggestions. Support groups can answer questions that can other people with cancer can understand.
Plan ahead. It may be hard to do, but ask your health care team about advance directives. Taking these steps now will give your family guidance on your medical choices if or when you can no longer speak for yourself.
Sources: Mayo Clinic, Mesothelioma.com and the American Cancer Society