Mesothelioma Clinical Staging

The treatment and outlook for those with mesothelioma depends a great deal on the stage of their cancer. Because the most frequently occurring type of mesothelioma is pleural, and it is also the one most studied, it is the only type for which a staging system exists. The following stages are based on a system known as the Butchart system, which divides mesothelioma into four stages:

• Stage I: Mesothelioma is found within the right or the left pleura and may also involve the lung, the pericardium, or the diaphragm on the same side.
• Stage II: In this stage, mesothelioma has spread to the chest wall or involves the esophagus, the heart, or the pleura on both sides. The lymph nodes in the chest may be involved as well.
• Stage III: Mesothelioma has gone through the diaphragm and into the lining of the abdominal cavity. Additional lymph nodes besides those in the chest may be involved.
• Stage IV: There is evidence that mesothelioma has spread through the bloodstream to distant organs or tissues.

Another system of staging mesothelioma is based on a TNM system (T=tumor, N=spread to lymph nodes, and M=metastasis). There are minor differences between this and the Butchart system. It is more detailed and precise, but the original Butchart system is still the one most often used to describe pleural mesotheliomas.

There are treatments available for all patients with malignant mesothelioma. The three kinds of treatment used are surgery, radiation therapy, and chemotherapy.

Surgery is a common treatment for mesothelioma. It is not an option unless the cancer is limited to one place and unless the person can withstand the surgery. During surgery, the physician may remove a portion of the lining of the chest (pleurectomy) or abdomen (peritonectomy) and some of the tissue surrounding it. Depending on the extent the disease has spread, a lung may also require removal (extrapleural pneumonectomy ). Occasionally, a portion of the diaphragm is taken out as well. If treatment is not possible, other less invasive measures can be used to relieve the patient's symptoms. For example, a needle placed into the chest cavity (thoracentesis ) can remove excess fluid in the chest. If recurrence of fluid causes symptoms, a nonsurgical or surgical method can be used to scar the lining of lung cavity and cause it to adhere to the lung. The procedure obliterates the pleural space and thus prevents the fluid from reaccumulating. (This procedure is called sclerosis or sclerotherapy.) These methods are called palliative, for they are not meant to cure the cancer but to improve symptoms.

Radiation therapy uses high-energy x rays to kill cancer cells and cause tumor shrinkage. It is rarely used as the primary treatment for pleural mesothelioma in those patients for whom surgery is not an option. It may also be used as an adjunct to surgery or as a method of alleviating various symptoms like trouble with swallowing, pain, and shortness of breath.

Chemotherapy involves the use of drugs to kill cancer cells. The most commonly used drugs are doxorubicin , cisplatin , and methotrexate . The medicines are delivered into a vein or taken by mouth. In the treatment of mesothelioma, they may also be injected directly into the chest or abdominal cavity. Chemotherapy may be given as the main treatment or may be an addition to surgery, depending on the type and stage of the cancer.

A new treatment being studied for early stages of mesothelioma confined to the chest is called intraoperative photodynamic therapy. This treatment uses special drugs that make cancer cells more sensitive to killing by a laser light. The drugs are given several days before surgery. During surgery, the special light is used to shine on the pleura.

By the time symptoms show up and mesothelioma is diagnosed, the disease is often advanced. The average survival period after diagnosis is about one year. If the cancer is found before it has spread and it is treated aggressively, about half of the patients will live two years, and approximately 20% will survive five years.