Mesothelioma is a rare cancer that begins in the lining of the internal organs of the body. Approximately three-fourths of cases of mesothelioma begin in the lining surrounding the lungs (called pleural mesothelioma). While pleural mesothelioma does begin in the chest cavity, it does not start in the lungs, and it is often incorrectly grouped with lung cancer. Mesothelioma that begins in the tissue surrounding the abdominal area (called peritoneal mesothelioma) accounts for about 10% to 20% of cases.
There are three main types of mesothelioma:
Epithelial type. The epithelial type accounts for 50% to 70% of people diagnosed with mesothelioma. It has the best prognosis (chance of recovery) due to its slower growth, and this type is more likely to respond to treatment.
Sarcoma type. The sarcoma type accounts for 7% to 20% of people diagnosed with mesothelioma and has a worse prognosis.
Mixed type. The mixed type accounts for 20% to 35% of people diagnosed with mesothelioma and contains both epithelial and sarcomatous types. This type of mesothelioma has an intermediate prognosis.
Cancer begins when cells become abnormal, grow uncontrollably, and eventually form a tumor. Tumors can be benign (non-cancerous) or malignant (cancerous, meaning it can spread to other parts of the body). This section covers malignant mesothelioma.
Statistics
It is estimated that 2,000 to 3,000 cases of mesothelioma are diagnosed each year in the United States. Men in their mid-60s are most often affected by mesothelioma because of an occupational exposure to asbestos, but women are also diagnosed with this disease.
The past decade has seen an increase in mesothelioma that can be attributed to the long latency period between asbestos exposure and development of symptoms of mesothelioma.
The five-year relative survival rate (percentage of patients who survive at least five years after the cancer is detected, excluding those who die from other diseases) of patients with mesothelioma is about 10%. The average survival for a person with mesothelioma is about 1 to 2 years. These numbers reflect the fact that most cases are advanced at the time of diagnosis.
However, cancer survival statistics should be interpreted with caution. These estimates are based on data from thousands of cases of this type of cancer in the United States each year, but the actual risk for a particular individual may differ. It is not possible to tell a person how long he or she will live with mesothelioma. Because the survival statistics are measured in five-year (or sometimes one-year) intervals, they may not represent advances made in the treatment or diagnosis of this cancer.
A risk factor is anything that increases a person’s chance of developing cancer. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health-care choices.
The following factors can raise a person’s risk of developing mesothelioma:
Asbestos exposure. Between 70% to 80% of people diagnosed with mesothelioma have a history of occupational asbestos exposure. Asbestos is a group of natural minerals found in the earth. Because of its strong, flexible fibers, asbestos was once commonly added to cement, insulation, roof shingles, and other products. People involved in the manufacturing of products containing asbestos or their installation and maintenance can breathe in or swallow the asbestos fibers. These fibers can also be carried in asbestos dust on clothing or personal items, exposing family members of the workers to potentially high levels of the minerals. Current safety regulations require people who work with asbestos to wear protective equipment and to shower and change clothes before leaving the workplace.
Smoking. Smoking by itself does not increase the risk of mesothelioma, but the combination of smoking and asbestos exposure greatly increases the risk of certain types of cancer in the lung.
Radiation exposure. Radiation exposure may cause mesothelioma.
Zeolite exposure. Exposure to a type of mineral called zeolite may cause mesothelioma.
Infection. Infection with certain viruses, such as the simian virus 40 (SV40), may be associated with mesothelioma, although this link has not been proven.
Even though some cases of mesothelioma occur with no known risk factors, many cases of mesothelioma can be traced to asbestos or chemical exposure. Therefore, it is important to always wear protective gear when working with asbestos.
People with mesothelioma may experience the following symptoms. Sometimes, people with mesothelioma do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not cancer. Often, symptoms of mesothelioma may not appear until years or even decades after asbestos exposure. If you are concerned about a symptom on this list, please talk to your doctor.
General symptoms of mesothelioma may include:
Weight loss
Fatigue
Problems with blood clotting
Anemia (low level of red blood cells)
Fever
Night sweats
If mesothelioma is in the lung area, symptoms may include:
Shortness of breath, caused by fluid from the cancer or the increasing size of the tumor limiting the amount of chest space for the lungs to expand
Pain in the chest area
If mesothelioma is in the abdominal area, symptoms may include:
Doctors use many tests to diagnose cancer and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your doctor may consider these factors when choosing a diagnostic test:
Age and medical condition
The type of cancer suspected
Severity of symptoms
Previous test results
The diagnosis of mesothelioma is challenging. The diagnosis can be difficult to determine, or it can be confused with other diseases, such as lung cancer.
Many people first note symptoms of mesothelioma when they develop fluid in the space around the lungs (called pleural effusion). When this fluid is removed, it can be analyzed to see if there are cancer cells in it. However, testing this fluid is usually not the only test needed to diagnose the disease.
Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease). Typically, a biopsy is required to confirm a diagnosis of mesothelioma. In some cases, a needle can be used to get a sample of the lining. More often, though, a surgical procedure (such as a video thoracoscopy) is performed to examine the chest cavity and take tissue samples.
The following procedures may be used to help develop a treatment plan:
Physical examination. A physical examination may include a medical history of the person and his or her family's past illnesses, inventory of their risk factors (including asbestos exposure), and an examination for other signs of cancer.
Lung function tests. Also called pulmonary function tests (PFTs), lung function tests evaluate how much air the lungs can hold, how quickly air can move in and out of the lungs, and how well the lungs add oxygen and remove carbon dioxide from the blood.
X-ray. An x-ray is a picture of the inside of the body. An x-ray of the chest can sometimes help doctors determine the presence and location of mesothelioma, but is not the primary method of diagnosing mesothelioma.
Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then puts these images into a detailed, cross-sectional view that shows abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium (a special dye) may be injected into a patient’s vein to create a clearer picture.
Positron emission tomography (PET) scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images.
Staging is a way of describing a cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancers.
One tool that doctors use to describe the stage is the TNM system. This system uses three criteria to judge the stage of the cancer: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to the rest of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer so doctors can work together to plan the best treatments.
TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:
How large is the primary tumor and where is it located? (Tumor, T)
Has the tumor spread to the lymph nodes? (Node, N)
Has the cancer metastasized (spread) to other parts of the body? (Metastasis, M)
Tumor. Using the TNM system, the "T" plus a letter and/or number (0 to 4) is used to describe the stage of the tumor. Some stages are also divided into smaller groups that help describe the tumor in even more detail. This helps the doctor develop the best treatment plan for each patient. Specific tumor stage information is listed below:
TX: The primary tumor cannot be evaluated.
T0: There is no tumor.
T1: The tumor invades the ipsilateral parietal pleura (the thin membrane that lines the inner chest walls on the same side of the body as the tumor), with or without involvement of the visceral pleura (the innermost of the two layers of the pleura).
T1a: The tumor invades the ipsilateral parietal pleura, with no involvement of the visceral pleura.
T1b: The tumor invades the ipsilateral parietal pleura, with involvement of the visceral pleura.
T2: The tumor invades any of the ipsilateral pleural surfaces with at least one of the following: visceral pleural tumor, invasion of the diaphragmatic muscle (the muscle that separates the chest cavity from the abdomen), or invasion of the lung.
T3: The tumor involves any of the ipsilateral pleural surfaces, with at least one of the following: invasion of the endothoracic fascia (the membrane that surrounds the thorax) and/or invasion into mediastinal fat.
T4: The tumor involves any of the ipsilateral pleural surfaces, with at least one of the following: diffuse or multifocal invasion of soft tissues of the chest wall, any involvement of rib, invasion through the diaphragm to the peritoneum, invasion of any mediastinal organ(s), direct extension to the contralateral pleura, invasion into the spine, extension to the internal surface of the pericardium, pericardial effusion with positive cytology, invasion of the myocardium, and/or invasion of the brachial plexus.
Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the chest are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The regional lymph nodes cannot be assessed.
N0 (N plus zero): There is no regional lymph node metastasis.
N1: There is metastasis to the ipsilateral bronchopulmonary and/or hilar lymph node(s).
N2: There is metastasis to the subcarinal lymph node(s) and/or the ipsilateral internal mammary or mediastinal lymph node(s).
N3: There is metastasis to the contralateral mediastinal, internal mammary, or hilar lymph node(s) and/or the ipsilateral or contralateral supraclavicular or scalene lymph node(s).
Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread to other parts of the body.
MX: Distant metastasis cannot be evaluated.
M0 (M plus zero): There is no distant metastasis.
M1: There is metastasis to other parts of the body.
Cancer stage grouping
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage I: The tumor has invaded the ipsilateral parietal pleura, with or without involvement of the visceral pleura, but has not spread to the lymph nodes or other parts of the body (T1, N0, M0).
Stage IA: The tumor has invaded the ipsilateral parietal pleura, without involvement of the visceral pleura, but has not spread to the lymph nodes or other parts of the body (T1a, N0, M0).
Stage IB: The tumor has invaded the ipsilateral parietal pleura, with involvement of the visceral pleura, but has not spread to the lymph nodes or other parts of the body (T2a, N0, M0).
Stage II: The tumor has invaded any of the ipsilateral pleural surfaces with at least one of the following: visceral pleural tumor, invasion of the diaphragmatic muscle, or invasion of the lung. The cancer has not spread to the lymph nodes or throughout the body (T2, N0, M0).
Stage III: The cancer has invaded any of the ipsilateral pleural surfaces with at least one of the following: visceral pleural tumor, invasion of the diaphragmatic muscle, or invasion of the lung; or the tumor involves any of the ipsilateral pleural surfaces, with at least one of the following: invasion of the endothoracic fascia (the membrane that surrounds the thorax), invasion into mediastinal fat with spread to the lymph nodes, but not to distant parts of the body. The cancer has also spread to the lymph nodes, but not throughout the body (T1 or T2, N1, M0; T1 or T2, N2, M0; T3, any N, M0).
Stage IV: The cancer involves any of the ipsilateral pleural surfaces, with at least one of the following: diffuse or multifocal invasion of soft tissues of the chest wall, any involvement of rib, invasion through the diaphragm to the peritoneum, invasion of any mediastinal organ(s), direct extension to the contralateral pleura, invasion into the spine, extension to the internal surface of the pericardium, pericardial effusion with positive cytology, invasion of the myocardium, and/or invasion of the brachial plexus. Stage IV can also mean that the tumor is of any size and the cancer has spread to distant lymph nodes, or the cancer has spread to other parts of the body (T4, Any N, M0; any T, N3, M0; or any T, any N, M1).
Recurrent: This is cancer that has come back after treatment. It may return in the chest or in another part of the body.
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Sixth Edition (2002) published by Springer-Verlag New York, www.springer-ny.com.
The treatment of mesothelioma depends on the size and location of the tumor, whether the cancer has spread, and the person’s overall health. In many cases, a team of doctors will work with the patient to determine the best treatment plan. For mesothelioma, there are three main types of treatment: surgery, radiation therapy, and chemotherapy.
This section outlines treatments that are the standard of care (the best treatments available) for this specific type of cancer. Patients are also encouraged to consider clinical trials as a treatment option when making treatment plan decisions. A clinical trial is a research study to test a new treatment to prove it is safe, effective, and possibly better than standard treatment. Your doctor can help you review all treatment options. For more information, visit the Clinical Trials section.
Surgery
The type of surgery for mesothelioma depends on the stage and location of the cancer. A surgeon may remove the affected lining. In the case of pleural mesothelioma, this is called a pleurectomy, and in peritoneal mesothelioma, it is called a peritonectomy. Generally, the tumor cannot be completely removed with these procedures. A more aggressive surgery for pleural mesothelioma is called an extrapleural pneumonectomy. This involves removing not just of the lining of the lung, but also the entire lung itself, a portion of the diaphragm, and often a portion of the lining around the heart. This is a difficult surgery and is recommended only after the doctor has reviewed a number of factors, including the patient’s overall health and the stage of the disease. If the entire tumor cannot be removed, other treatments such as radiation therapy or chemotherapy may be recommended.
Radiation therapy
Radiation therapy is the use of high-energy x-rays or other particles to kill cancer cells. The most common type of radiation treatment is called external-beam radiation, which is radiation given from a machine outside the body. When radiation treatment is given using implants, it is called internal radiation therapy or brachytherapy.
Side effects from radiation therapy include tiredness, mild skin reactions, upset stomach, and loose bowel movements. Most side effects go away soon after treatment is finished.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. The side effects of chemotherapy depend on the individual and the dose used, but can include fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually go away once treatment is finished.
The chemotherapy treatment best studied in mesothelioma is the combination of pemetrexed (Alimta) and cisplatin (Platinol). These medications are given intravenously (by vein) every three weeks. The most common side effects include, but are not limited to, nausea, vomiting, damage to the kidneys, numbness and tingling in the fingers or toes, decreased hearing, rash, fatigue, lowering of the white blood count making one susceptible to infection, or lowering of the red blood count (anemia). Patients on this treatment may be given vitamins (B12 and folic acid) to decrease the risk of these side effects. Other medications, such as antinausea medications, are also available to relieve many of these side effects.
The medications used to treat cancer are continually being evaluated. Talking with your doctor is often the best way to learn about the medications prescribed for you, their purpose, and their potential side effects or interactions with other medications. Learn more about your prescriptions through Cancer.Net's Drug Information Resources, which provides links to searchable drug databases.
Palliative therapy
The goal of palliative therapy is to relieve the symptoms that result from the cancer and cancer treatment, to improve the patient’s quality of life. Examples of palliative care for mesothelioma include draining fluid that has built up in the patient’s chest or abdomen, or using radiation therapy or chemotherapy to relieve symptoms.
Doctors and scientists are always looking for better ways to treat patients with mesothelioma. A clinical trial is a way to test a new treatment to prove that it is safe, effective, and possibly better than a standard treatment. Patients who participate in clinical trials are among the first to receive new treatments before they are widely available. However, there is no guarantee that the new treatment will be safe, effective, or better than a standard treatment.
Patients decide to participate in clinical trials for many reasons. For some patients, a clinical trial is the best treatment option available. Because standard treatments are not perfect, patients are often willing to face the added uncertainty of a clinical trial in the hope of a better result. Other patients volunteer for clinical trials because they know that finding new drugs and other therapies is the only way to make progress in treating mesothelioma. Even if they do not benefit directly from the clinical trial, their participation may benefit future patients with mesothelioma.
To join a clinical trial, patients must complete a learning process known as informed consent. During informed consent, the doctor should list all of the patient’s options, so the person understands how the new treatment differs from the standard treatment. The doctor must also list all of the risks of the new treatment, which may or may not be different from the risks of standard treatment. Finally, the doctor must explain what will be required of each patient in order to participate in the clinical trial, including the number of doctor visits, tests, and the schedule of treatment. Learn more about clinical trials, including patient safety, phases of a clinical trial, deciding to participate in a clinical trial, questions to ask the research team, and links to find cancer clinical trials.
Cancer and its treatment can cause a variety of side effects. However, doctors have made major strides in recent years in reducing pain, nausea and vomiting, and other physical side effects of cancer treatments. Many treatments used today are less intensive but as effective as treatments used in the past. Doctors also have many ways to provide relief to patients when such side effects do occur.
Fear of treatment side effects is common after a diagnosis of cancer, but it may be helpful to know that preventing and controlling side effects is a major focus of your health-care team. Before treatment begins, talk with your doctor about possible side effects of the specific treatments you will be receiving. The specific side effects that can occur depend on a variety of factors, including the type of cancer, its location, the individual treatment plan (including the length and dosage of treatment), and the person’s overall health.
Ask your doctor which side effects are most likely to happen (and which are not), when side effects are likely to occur, and how they will be addressed by the health-care team if they do happen. Also, be sure to communicate with the doctor about side effects you experience during and after treatment. For more information on the most common side effects of cancer and different treatments, along with ways to prevent or control them, visit Cancer.Net’s section on Managing Side Effects, based on ASCO’s curriculum.
In addition to physical side effects, there may be psychosocial (emotional and social) effects as well. Learn more about the importance of addressing these needs in Cancer.Net’s section on Caring for the Whole Patient.
For more information on late effects or long-term side effects, please read the After Treatment section or talk with your doctor.
After treatment for mesothelioma ends, talk with your doctor about developing a follow-up care plan. This plan may include regular physical examinations and/or medical tests to monitor your recovery for the coming months and years.
People treated for mesothelioma are encouraged to follow established guidelines for good health, such as maintaining a healthy weight, not smoking, eating a balanced diet, and having recommended cancer screening tests. Talk with your doctor to develop a plan that is best for your needs. Moderate physical activity can help rebuild your strength and energy level. Your doctor can help you create an appropriate exercise plan based upon your needs, physical abilities, and fitness level. Learn more about Healthy Living After Cancer.
Research involving more advanced diagnostic procedures and treatment for mesothelioma is ongoing. The advancements described here may still be under investigation in clinical trials and may not be approved or available at this current time. Always discuss all diagnostic and treatment options with your doctor.
Researchers are evaluating new treatments for mesothelioma, including several promising new drugs, gene therapy, and immunotherapy. Research projects at various universities are underway to identify genes that become mutated that may cause mesothelioma and to find blood markers (a substance found in higher than normal amounts in the blood of someone with cancer) that could help detect early-stage mesothelioma.
Regular communication with your doctor is important in making informed decisions about your health care. Consider asking the following questions of your doctor:
What type of mesothelioma do I have?
Where exactly is the tumor located?
Can you explain my pathology report to me?
What is the stage of the cancer? What does this mean?
What treatment options are available?
What clinical trials are open to me?
What treatment do you recommend? Why?
What is the goal of this treatment?
What is my prognosis?
How will this treatment affect my daily life? Will I be able to work, exercise, and perform my usual activities?
What are the possible side effects of this treatment, both in the short term and the long term?
What follow-up tests will I need, and how often will I need them?
What support services are available to me? To my family?
How can I keep myself as healthy as possible during treatment?
In addition to treating my cancer, what can be done to treat my symptoms (such as pain medications or appetite stimulants)?
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