Mesothelioma

Mesothelioma is a serious type of cancer that develops in the mesothelium. The mesothelium is a thin layer of tissue that covers many internal organs.

This disease is significant because it can affect various parts of the body. Most commonly, it affects the lining of the lungs and the chest wall, which is called the pleura. It can also affect the lining of the abdomen, known as the peritoneum. In rarer cases, it may involve the sac surrounding the heart, or the sac surrounding the testes.

The way mesothelioma affects the body depends on its location. When it occurs in the pleura, it often causes pleural effusion. This is an accumulation of fluid in the pleural space. This buildup can lead to shortness of breath, a cough, or chest wall pain. In severe cases, a person might experience a pneumothorax, which is a collapsed lung. If the cancer reaches the abdomen, it can cause ascites. Ascites is an abnormal buildup of fluid in the abdominal cavity that causes swelling.

If the cancer affects the heart, it is called pericardial mesothelioma. This can lead to heart failure or cardiac tamponade, where the tumor interferes with the heart's ability to function. In very advanced stages, the cancer may undergo metastasis. This means the cancer spreads to other organs like the liver, kidneys, or adrenal glands.

Exposure to asbestos is the primary cause of mesothelioma. More than 80% of all cases are linked to asbestos exposure. Asbestos is a mineral fiber that was used widely in industrial products. These products included cement, brake linings, gaskets, and insulation. As of 2013, approximately 125 million people worldwide had been exposed to asbestos at work. Risk is higher for people who mine asbestos or produce asbestos products. It also affects those who work in buildings containing these materials. Even family members can face risks through paraoccupational secondary exposure. This happens if asbestos dust is brought home on clothing or hair. Washing the contaminated clothing of a worker can also increase this risk.

The relationship between asbestos and this cancer is unique because of the long delay. The onset of the disease is generally separated from the initial exposure by many years. This delay typically lasts between 25 and 70 years. Most cases peak between 30 and 40 years after the first exposure. However, some cases have been documented with only one to three months of exposure. Because of this strong link, many experts consider mesothelioma a "sentinel" tumor. This means its presence signals that asbestos exposure has likely occurred. Other potential risk factors include genetics and infection with the simian virus 40. Some researchers also study the potential risks of carbon nanotubes.

History shows how the use of asbestos changed the frequency of this disease. Mesothelioma was rare before the commercial use of asbestos began. The use of the mineral increased greatly during World War II. In the United States, many workers were exposed to asbestos dust starting in the early 1940s. In Wittenoom, Western Australia, commercial mining took place from 1937 to 1966. The first case of mesothelioma in that town was recorded in 1960. By 1994, there were 539 reported deaths due to the disease in Western Australia. In the United States, rates of mesothelioma have increased since the 1950s. Today, about 3,000 people in the U.S. are diagnosed each year.

Statistics provide a clear picture of the disease's impact. In 2015, about 60,800 people in the United States had mesothelioma. During that same year, approximately 32,000 people died from the disease. The average five-year survival rate in the United States is about 8%. Most diagnoses occur after the age of 65. Most deaths from the disease happen around the age of 70. The disease affects males more often than females. Global rates also vary, with higher rates in Australia and the United Kingdom. Japan reports lower rates of the disease.

Doctors use several methods to diagnose and treat the condition. A diagnosis may be suspected using a chest X-ray or a CT scan. To confirm the presence of cancer, doctors perform a biopsy. A biopsy involves examining a tissue sample or fluid produced by the cancer.

Treatment options often include surgery, radiation therapy, and chemotherapy. Chemotherapy frequently uses medications called cisplatin and pemetrexed. One specific procedure is called pleurodesis. In this procedure, substances like talc are used to scar the pleura together. This helps prevent the continuous buildup of fluid around the lungs.