Mesothelioma is a devastating cancer that usually begins in the mucous-covered lining of the lungs. It is almost always caused by asbestos exposure, though physical symptoms and lung damage may not appear for several decades following the time of exposure. Most doctors and medical centers recognize four stages of mesothelioma, classified based on the appearance of the initial lung tumor and the degree to which cancer has spread to other parts of the body. Early detection of mesothelioma is essential to provide the best chances of survival and recovery.
Stage I mesothelioma is characterized by subtle changes to a spot on the pleural lining around a lung or nearby in the chest cavity. An initial tumor is typically small, round, and discolored on diagnostic imaging scans. Cancer has not yet metastasized, or spread, to other sites in the body.
In stage II of mesothelioma, cancerous cells begin to engulf the pleural lining. A large portion of the lining of one or both lungs and the diagram is affected by the tumor. In addition, lymph nodes found deep within the lungs may be involved. A person usually does not experience physical symptoms during the first two stages of mesothelioma, so the cancer often goes undiagnosed until it has already metastasized and caused serious damage.
The last two stages of mesothelioma are typically the most severe. In stage III, cancer nearly engulfs the entire pleural lining and lymph nodes in the chest develop their own tumors. Shortness of breath, chest pains, coughing, and weight loss tend to gradually worsen during stage III. In stage IV, cancer starts spreading quickly to lymphatic tissue and nodes in the chest and possibly elsewhere in the body. Cancer can also begin to affect the gastrointestinal tract, muscles in the chest wall, airways, and the lining of the heart. Symptoms continue to worsen during the final stage, and many people become deathly ill without medical care.
When cancer is detected in the earliest stages of mesothelioma, a combination of surgery and chemotherapy is usually effective at eliminating the problem. A surgeon may be able to excise most or all of a tumor before it metastasizes to lymph nodes. Late stage mesothelioma is notoriously difficult to treat, but chemotherapy and radiation may be helpful at slowing the spread of cancer to the heart and other vital organs. Patients in the final stages of mesothelioma are often hospitalized so they can receive around-the-clock care and monitoring.