Diseases

Mesothelioma is diagnosed by pathological examination from a biopsy. Tissue is removed, placed under the microscope, and a pathologist makes a definitive diagnosis and issues a pathology report. This is the end of a process that usually begins with symptoms that send most people to the doctor: a fluid buildup around the lungs (pleural effusions), shortness of breath, pain in the chest, or pain or swelling in the abdomen. The doctor may order an X-ray or CT scan of the chest or abdomen. If further examination is warranted, the following tests may be done:

• Thoracoscopy: For pleural mesothelioma, the doctor may look inside the chest cavity with a special instrument called a thoracoscope. A cut will be made through the chest wall and the thoracoscope will be put into the chest between two ribs. This test is usually done in a hospital using an anesthetic. If fluid has collected in your chest, your doctor may drain the fluid out of your body by putting a needle into your chest and using gentle suction to remove the fluid. This is called thoracentesis.
• Peritoneoscopy: For peritoneal mesothelioma, the doctor may also look inside the abdomen with a special tool called a peritoneoscope. The peritoneoscope is put into an opening made in the abdomen. This test is usually done in the hospital under an anesthetic. If fluid has collected in your abdomen, your doctor may drain the fluid out of your body by putting a needle into your abdomen and using gentle suction to remove the fluid. This process is called paracentesis.
• Biopsy: If abnormal tissue is found, the doctor will need to cutout a small piece and have it looked at under a microscope. This is usually done during the thoracoscopy or peritoneoscopy, but can be done during surgery. Unfortunately, in some cases, tumor cells can grow along the tract where the biopsy is taken. This can be minimized with the use of radiation to the area.

People exposed in the 1940s, '50s, '60s, and '70s are now being diagnosed with mesothelioma because of the long latency period of asbestos disease.

An exposure of as little as one or two months can result in mesothelioma 30 or 40 years later and in some cases, as much as 70 years later.

New approaches being studied New approaches to treat malignant mesothelioma are currently being tested. They often combine traditional treatments or include something entirely new. They include:

• L-NDDP (Platar): Intrapleural administration of this platinum product is designed to overcome the toxicity and drug resistance currently limiting the usefulness of platinum drugs like Cisplatin. NOTE: A recent trial produced remission in two patients.
• Endostatin has been shown to work with angiostatin in destroying a tumors' ability to grow blood vessels without harming normal cells.
• Lovastatin is a cholesterol drug shown in a recent study to potentially inhibit mesothelioma cancer cell growth.
• Intrapleural interferon gamma is the direct administration of the anti-cancer drug interferon gamma.
• Photodynamic therapy kills cancer cells using the energy of light.
• Immunotherapy treats cancer by helping the immune system fight the disease.
• Gene therapy treats cancer by correcting the genetic deficits that allow tumors to develop. A September 1999 study found that interferon interleukin prevented the growth of mesothelioma cells in mice.

Research is being conducted at various cancer centers all over the United States. A recent study involving L-NDDP produced two cases of remission in mesothelioma patients. Another study found that a drug known as Lovastatin may hold promise for mesothelioma patients. To learn more about mesothelioma clinical studies and journal medical journal articles, visit the Mesothelioma Web (http://www.mesotheliomaweb.org).

Most people present with complaints of shortness of breath. They also can have complaints of chest pain and cough. Patients may also be asymptomatic, with the disease discovered by physical exam or an abnormal chest X-ray. As the disease progresses, shortness of breath increases, and weight loss, decreased appetite, and night sweats can develop. Local invasion by the tumor can result in changing of voice, loss of function of the diaphragm, and symptoms specific to the area and involvement of adjacent structures.

Most people with malignant mesothelioma have worked on jobs where they breathed asbestos. Usually, this involves men over 40 years of age. Others have been exposed to asbestos in a household environment, often without knowing it. The number of new cases of mesothelioma has been relatively stable since 1983, the same time that the restrictions on asbestos were instituted by the U.S. Occupational Safety and Health Administration (OSHA). In Europe, the number of new cases of mesothelioma continues to rise.

Mesothelioma is a rare form of cancer (malignancy) that most frequently arises from the cells lining the sacs of the chest (the pleura) or the abdomen (the peritoneum). Pleural mesothelioma is the most common form, often presenting with symptoms in the chest area. Peritoneal mesothelioma is much less common. This can affect the organs in the abdomen, and its symptoms are related to this area of the body, that is, abdominal swelling, nausea, vomiting, and bowel obstruction. The rarest form of mesothelioma is pericardial mesothelioma, which involves the sac surrounding the heart. There are two major cell types of mesothelioma, epithelial and sarcomatoid. Sometimes both of these cell types can be present. The sarcomatoid type is rarer and occurs in only about 15% of cases; it portends a poorer prognosis. In very rare cases, mesothelioma can originate from benign, non-malignant cells. This so-called benign mesothelioma can be cured surgically.

Like most cancers, the prognosis for this disease often depends on how early it is diagnosed and how aggressively it is treated. Unfortunately, mesothelioma is often found at a stage in which a cure is unobtainable. Many will succumb to the disease within one year of diagnosis. Mesothelioma treatment options (traditional and new treatments being studied) Treatment options are determined by the stage of mesothelioma (the extent to which the tumor has spread in the body). There are three staging systems currently in use, and each one measures somewhat different variables. The oldest staging system and the one most often used is the Butchart system, which is based mainly on the extent of primary tumor mass and divides mesotheliomas into four stages. Butchart system extent of primary tumor mass

• Stage I: Mesothelioma is present in the right or left pleura and may also involve the diaphragm on the same side.
• Stage II: Mesothelioma invades the chest wall or involves the esophagus, heart, or pleura on both sides. Lymph nodes in the chest may also be involved.
• Stage III: Mesothelioma has penetrated through the diaphragm into the lining of the abdominal cavity or peritoneum. Lymph nodes beyond those in the chest may also be involved.
• Stage IV: There is evidence of metastasis or spread through the bloodstream to other organs.

The more recent TNM system considers variables of tumor in mass and spread, lymph node involvement, and metastasis. TNM system: variables of T (tumor), N (lymph nodes), and M (metastasis)

• Stage I: Mesothelioma involves right or left pleura and may also have spread to the lung, pericardium, or diaphragm on the same side. Lymph nodes are not involved.
• Stage II: Mesothelioma has spread from the pleura on one side to nearby lymph nodes next to the lung on the same side. It may also have spread into the lung, pericardium, or diaphragm on the same side.
• Stage III: Mesothelioma is now in the chest wall, muscle, ribs, heart, esophagus, or other organs in the chest on the same side with or without spread to lymph nodes on the same side as the primary tumor.
• Stage IV: Mesothelioma has spread into the lymph nodes in the chest on the side opposite the primary tumor, extended to the pleura or lung on the opposite side, or directly extended into organs in the abdominal cavity or neck. Any distant metastases is included in this stage.

The Brigham system is the latest system and stages mesothelioma according to resectability (the ability to surgically remove the tumor) and lymph node involvement. Brigham system: variables of tumor resectability and nodal status

• Stage I: resectable mesothelioma and no lymph node involvement
• Stage II: resectable mesothelioma but with lymph node involvement
• Stage III: unresectable mesothelioma extending into chest wall, heart, or through diaphragm, peritoneum; with or without extrathoracic lymph-node involvement
• Stage IV: distant metastatic disease

There are three traditional kinds of treatment for patients with malignant mesothelioma. Often two or more of these are combined in the course of treatment:

• surgery (taking out the cancer),
• radiation therapy (using high-dose X-rays or other high-energy rays to kill cancer cells), and
• chemotherapy (using drugs to fight the cancer).

Additional information Surgery: There are several types of surgery used in treating mesothelioma.

• A pleurectomy is the removal of part of the chest or abdomen lining and some of the tissue around it.
• Depending on how far the cancer has spread, a lung also may be removed in an operation called a pneumonectomy.
• In an extrapleural pneumonectomy, the lung is removed along with the lining and diaphragm (the muscle that helps you breathe) on the affected side. In this surgery, the lining around the heart is also removed.
• Sometimes a pleurectomy/decortication is performed. In this surgery, the lining of the lung is removed along with as much of the tumor as possible.

Radiation therapy uses high-energy X-rays to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external radiation therapy) or from putting materials that produce radiation (radioisotopes) through thin plastic tubes in the area where the cancer cells are found (internal radiation therapy). If fluid has collected in the chest or abdomen, your doctor may drain the fluid out of your body by putting in a needle into the chest or abdomen and using gentle suction to remove the fluid. If fluid is removed from the chest, this is called thoracentesis. If fluid is removed from the abdomen, this is called paracentesis. Your doctor may also put drugs through a tube into the chest to prevent more fluid from accumulating. Chemotherapy is the use of drugs to kill cancer cells. Chemotherapy may be administered by pill, or it may be put into the body by a needle in the vein or muscle. Chemotherapeutic agents can be administered either systemically (through the bloodstream) or intrapleurally (in the pleural cavity). When it is administered intrapleurally, the treatment is localized at the site of the tumor. These drugs are generally very toxic and you should discuss their use very carefully with your physician.

There are numerous cancer web sites, some specific to mesothelioma. Because they are often difficult to locate, we have listed some relevant medical web sites that have information about mesothelioma. American Institute for Cancer Research (http://www.aicr.org) American Thoracic Society (http://www.thoracic.org/) Canadian Cancer Society (http://www.bc.cancer.ca) Mesothelioma Web (http://www.mesotheliomaweb.org)