The body's organs and major cavities are lined with mesothelial cells that form a protective barrier which supports and lubricates organs and tissues. When cancer develops in this lining, it is called mesothelioma. Around three thousand cases of mesothelioma are diagnosed every year in the US, which is approximately three percent of cancer diagnoses.
There are four known types of malignant mesothelioma, each named after its point of origin in the body.
- Around 70% of mesothelioma is pleural, developing in the lining of the lungs (pleura) See Types of Mesothelioma - Pleural for more information.
- Around 25% of cases develop in the lining of the abdomen, called the peritoneal membrane. See Types of Mesothelioma - Peritoneal.
- Pericardial mesothelioma accounts for less than 5% of cases, and develops in the lining of the heart. See Types of Mesothelioma - Pericardial.
- The rarest type of mesothelioma develops in the lining of the testicles, called the tunica vaginalis. Fewer than 100 cases have been recorded.
Why does Mesothelioma Develop?
Malignant mesothelioma is caused by exposure to asbestos (however, in very rare cases a benign form of mesothelioma can develop without any asbestos exposure). Asbestos was widely used in the twentieth century in many industries, including manufacturing, construction, and ship-building, leading to exposure for millions of Americans. Please see "Asbestos Overview" for more information about asbestos and its uses.
While there is no doubt that asbestos exposure causes mesothelioma, the exact way in which this occurs is not completely understood. It is believed that inhalation of asbestos fibers leads to chronic inflammation, and this eventually causes mesothelial cells to mutate, which changes their DNA. Mesothelioma can develop if a mesothelial cell mutates in a way that allows it to become cancerous. For more information, please see Causes of Mesothelioma.
What Happens during Mesothelioma Diagnosis?
Mesothelioma diagnosis is a difficult process. One reason for this is that this type of cancer has a very long latency period—generally between three and five decades. This means someone who has been exposed to asbestos may appear healthy for many years before they develop any noticeable symptoms. For most people, cancer has already advanced to Stage II or even further by the time they are diagnosed. This is one reason why mesothelioma treatments are ineffective for most people.
Another issue that causes problems for diagnosing mesothelioma is that symptoms of the cancer are nonspecific. In the early stages of pleural mesothelioma, symptoms are easily mistaken for flu or pneumonia, while in the case of pericardial mesothelioma, the disease can be mistaken for other cardiac conditions. For more information about symptoms, please see Symptoms of Mesothelioma.
During the diagnostic process you'll need to give your doctor a full medical history, including details of asbestos exposure, if you know you were exposed. In addition you'll undergo a medical exam and a series of diagnostic tests. These tests will usually include an x-ray, MRI, and other medical imaging tests, as well as a biopsy that takes a sample of cells or fluid to test for the presence of cancer.
These diagnostic tests will determine not only whether cancer is present, but also how far it has progressed. Results of these tests provide a diagnosis, and help your doctors determine your best treatment options. For further information, please see Stages of Mesothelioma and Diagnosing Mesothelioma.
The difficulty of diagnosing mesothelioma—and the resistance of the disease to treatment—means that most people have a poor prognosis when they are diagnosed. Currently less than 50% of people with mesothelioma survive more than two years post-diagnosis.
I've been diagnosed with Mesothelioma-what are my Treatment Options?
Mesothelioma treatments fall into two main categories-curative and palliative. Curative are those carried out to try and cure a patient by removing or killing all cancer cells in the body. Palliative treatments are carried out to reduce pain and discomfort, to improve a patient's quality of life.
In general, you'll have three main options for curative treatment-surgery, chemotherapy, and radiation therapy. These are often given in conjunction with one another. For example, you might undergo surgery to remove a tumor, then receive a course of chemotherapy to kill any remaining cancer cells.