Mesothelioma

Mesothelioma is a tumor of the tissue that lines your lungs, stomach, heart, and other organs (the mesothelium). Mesothelioma usually starts in the lungs, but can also start in the abdomen or other organs. It can be benign (not cancer) or malignant (cancer..

Malignant mesothelioma is a rare but serious type of cancer. Most people who get it have worked on jobs where they inhaled asbestos particles. After being exposed to asbestos, it usually takes at least 20 years for the disease to form.

It is hard to tell the difference between malignant mesothelioma and lung cancer. Imaging tests and a biopsy will be used to make the diagnosis. Malignant mesothelioma is often found when it is advanced, which makes it harder to treat. Mesothelioma treatments are available, including surgery, radiation, and/or chemotherapy, but, for many people with mesothelioma, a cure is not possible.

Signs and symptoms of mesothelioma vary depending on where the cancer occurs.

Pleural mesothelioma affects the tissue that surrounds the lungs. It causes signs and symptoms that may include:

• chest pain under the rib cage
• painful coughing
• shortness of breath or trouble breathing
• unusual lumps of tissue under the skin on your chest
• unexplained weight loss

Peritoneal mesothelioma occurs in tissue of the abdomen. It causes signs and symptoms that may include:

• abdominal pain
• abdominal swelling
• lumps of tissue in the abdomen
• unexplained weight loss

In general, cancer begins when a series of genetic mutations occur within a cell, causing the cell to grow and multiply out of control. It is not clear what causes the initial genetic mutations that lead to mesothelioma, though researchers have identified factors that may increase the risk. It is likely that cancers form because of an interaction between many factors, such as inherited conditions, the environment, other health conditions, and lifestyle choices. Most cases of mesothelioma are caused by exposure to asbestos.

If you have signs and symptoms that might indicate mesothelioma, your doctor will conduct a physical exam to check for any lumps or other unusual signs. He or she may also order imaging scans, such as a chest X-ray and a computerized tomography (CT) scan of your chest or abdomen, to look for abnormalities. Further testing to determine whether mesothelioma or another disease is causing your signs and symptoms may be warranted.

A biopsy (a procedure to remove a small portion of tissue for laboratory examination) is the only way to determine whether you have mesothelioma. Depending on what area of your body is affected, your doctor selects the right biopsy procedure for you. The tissue sample is analyzed under a microscope to see whether the abnormal tissue is mesothelioma and what types of cells are involved. The type of mesothelioma you have determines your treatment plan.

Options to examine your internal organs and obtain tissue samples include:

• fine-needle aspiration, in which the doctor removes fluid or a piece of tissue with a small needle inserted into your chest or abdomen
• thoracoscopy, which allows the surgeon to see inside your chest with a tiny video camera is then inserted into your chest cavity
• laparoscopy, which allows the surgeon to see inside your abdomen with a tiny camera
• thoracotomy, which is surgery to open your chest between the ribs to allow a surgeon to check for signs of disease
• laparotomy, which is surgery to open your abdomen to allow a surgeon to check for signs of disease

Once mesothelioma is diagnosed, your doctor orders other tests to determine the extent, or stage, of the cancer. Imaging tests that may help determine the stage of your cancer may include:

• CT scans of the chest and abdomen
• magnetic resonance imaging (MRI)
• positron emission tomography (PET)

Once the extent of pleural mesothelioma is determined, a stage is assigned.

• Stage I mesothelioma is considered localized cancer, meaning it is limited to one portion of the lining of the chest.
• Stage II mesothelioma may have spread beyond the lining of the chest to the diaphragm or to a lung.
• Stage III mesothelioma may have spread to other structures within the chest and may involve nearby lymph nodes.
• Stage IV mesothelioma is advanced cancer that has spread more extensively within the chest. Stage IV may also indicate that mesothelioma has spread to distant areas of the body, such as the brain, liver and lymph nodes elsewhere in the chest.

A diagnosis of mesothelioma can be devastating for you and for your family and friends. There are several steps you can take to regain a sense of control.

Learn enough about mesothelioma in order to make decisions about your care. Write down questions to ask your doctor. Ask your health care team for information to help you better understand your disease.

Surround yourself with a support network. Close friends or family can help you with everyday tasks, such as getting you to appointments or treatment. If you have trouble asking for help, learn to be honest with yourself and accept help when you need it.

Seek out other people with cancer. Ask your health care team about cancer support groups in your community. Sometimes there are questions that can only be answered by other people with cancer. Support groups offer a chance to ask these questions and receive support from people who understand your situation.

Plan ahead. Ask your health care team about advance directives that give your family guidance on your medical wishes in case you can no longer speak for yourself.

Treatment for mesothelioma depends on your overall health and certain aspects of your cancer, such as its stage and location.

Unfortunately, mesothelioma often is an aggressive disease and for most people a cure is not possible. Mesothelioma is usually diagnosed at an advanced stage when it is not possible to remove the cancer through surgery. Instead, your doctor may work to control your cancer to make you more comfortable.

Three types of standard treatment are used for mesothelioma:

Surgery. Surgery can be used to remove the cancer and some of the healthy tissue around it; to remove the lining of the chest and the surface of the lungs; to remove a lung or other internal organs; and to stop the build-up of fluid in the chest.

Radiation therapy. Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.

Chemotherapy. Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Common chemotherapy drugs used in mesothelioma include:

• cisplatin (Platinol, Platinol-AQ)
• gemcitabine (Gemzar)
• pemetrexed Disodium (Alimta)

New types of treatment for mesothelioma are being tested in clinical trials.

Biologic therapy. Biologic therapy is a treatment that uses the patient’s immune system to fight cancer.

Targeted therapy. Targeted therapy is a type of treatment that uses drugs or other substances to attack specific cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do. Monoclonal antibodies and kinase inhibitors are types of targeted therapies being studied in the treatment of malignant mesothelioma.