What is Mesothelioma?
Throughout the body, layers of specialized cells line the interior of the chest, the abdomen and the area around the heart. The cells also cover the outer surface of most internal organs. This lining of specialized cells is referred to as the mesothelium. Tumors that originate within this lining are called mesotheliomas.
The medical community began recognizing mesothelioma in full in the early part of the 20th century. Prior to that they theorized it must be a metastatic cancer linked to a primary tumor elsewhere in the body, as opposed to existing independently.
Doctors now divide mesothelioma up into different types based on its location. The most common type of mesothelioma — three out of four cases — affects the tissue that surrounds the lungs, or the pleura, and is thus called pleural mesothelioma. Most other cases are abdomen-related cases, or peritoneal mesotheliomas. While very rare, there are also types of mesothelioma that affect the covering around the heart, pericardial mesotheliomas, and the area around the testicles, or mesotheliomas of the tunica vaginalis.
Some tumors that begin in the mesothelium are benign. Such tumors are generally removed by surgery and require no further treatment.
Malignant, or cancerous, mesotheliomas are classified into three types based on how the cancer cells are arranged. The most common type, accounting for about half of mesothelioma cases, is epithelioid. About 10 percent are described as sarcomatoid, or fibrous. And the remaining 30 to 40 percent are a combination (or, biphasic) of both epithelioid and sarcomatoid.
Symptoms, or signs, of mesothelioma vary depending on the location of the cancer. The most common type, pleural mesothelioma, affects the tissue around the lungs and its signs might include painful coughing, shortness of breath, unexplained weight loss, chest pain under the rib cage or unusual lumps of tissue under the skin on the chest area. Mesothelioma occurring in the abdominal area, or peritoneal mesothelioma, causes symptoms such as abdominal pain and swelling, lumps of tissue in the abdomen and unexplained weight loss.
Like other forms of cancers, treatment for malignant mesothelioma depends on the location and extent of the tumor. Treatments might include surgery, radiation therapy, chemotherapy or a combination of these approaches. Patients might also explore alternative therapies.
Unfortunately, mesothelioma can be difficult to treat. It generally does not grow as a single tumor mass, but rather spreads along nearby surfaces, nerves and blood vessels, making it hard to attack using traditional treatments such as surgery or radiation.
Individuals diagnosed with malignant mesothelioma face daunting odds. According to the National Cancer Institute, the relative 5-year survival rate for mesothelioma — or the percentage of people who live longer than five years after being diagnosed — is between 5 and 10 percent.