Malignant mesothelioma is an extremely rare form of cancer that affects the mesothelial cells which line organs such as the lungs, the abdominal organs, or the heart. This disease is caused by exposure to asbestos, a naturally-occurring mineral that has been used in a wide range of applications throughout human history.
Before the 1970s, asbestos was used for a variety of products humans come into contact with every day, including but certainly not limited to:
Most mesothelioma patients can trace their exposure to asbestos to their professions, though many cases of non-occupational and second-hand asbestos exposure causing mesothelioma are documented. While there is no safe level of asbestos exposure, it is important to note that malignant mesothelioma is a very rare disease, with only 3,000 individuals in the United States receiving a mesothelioma diagnosis every year.
There are three main types of malignant mesothelioma, which are named according to the area of the body in which the cancer originates:
This asbestos cancer strikes the mesothelial cells that line the lungs, known as the pleura, and it is by far the most common form of the disease. Most patients are between the ages of 50-80 years when they are diagnosed with pleural mesothelioma.
Pleural mesothelioma is the most common form of this rare and deadly cancer, accounting for up to 80 percent of all mesothelioma diagnoses. It is caused by inhalation of airborne asbestos fibers, which lodge in the protective tissue around the lungs known as the pleura. This can cause irritation, inflammation, and scarring, and in some cases it can cause mutations in pleural cells to form cancerous mesothelioma tumors.
Pleural mesothelioma is often diagnosed at an advanced stage, and as a result the prognosis for patients with this type of cancer is low, with only roughly 10 percent of patients surviving five years after diagnosis. Still, a number of pleural mesothelioma treatments are currently showing promise in clinical trials, and doctors are hopeful that they will be able to extend the life expectancy of pleural mesothelioma patients in the future.
Diagnosis and Symptoms of Pleural Mesothelioma
Pleural mesothelioma is sometimes initially misdiagnosed because many pleural mesothelioma symptoms are similar to those exhibited by individuals with a number of more common diseases, such as the flu or lung cancer. Diagnostic aids such as X-rays, CT scans, and PET scans can help detect signs of cancer, and biopsies and cytologic analyses are used to arrive at a definitive diagnosis of pleural mesothelioma.
Most pleural mesothelioma symptoms are a result of a buildup of fluid between the pleura, known as pleural effusion. This puts pressure on the lungs, which can lead to the following symptoms:
Peritoneal mesothelioma affects the mesothelial cells of the peritoneum, which line the abdominal cavity. Patients are an average of 63 to 71 years old when they are diagnosed with peritoneal mesothelioma, and most patients live only an average of 13 months after diagnosis.Peritoneal mesothelioma affects 10 to 20 percent of all mesothelioma patients and is the second most common form of this disease. Between 300 and 600 cases of peritoneal mesothelioma are diagnosed in the United States every year. In some cases, exposure to asbestos can cause the cells in the peritoneum to mutate and form cancerous tumors typical of patients with peritoneal mesothelioma.
While some patients have been known to survive several years after being diagnosed with peritoneal mesothelioma, these patients are the exception and not the rule. In truth, life expectancy for peritoneal mesothelioma patients is close to one year after diagnosis.
In many cases, symptoms of peritoneal mesothelioma do not present for up to 20 to 50 years after a person is exposed to asbestos. Peritoneal mesothelioma is a very rare form of cancer, so it is often diagnosed at late stages because doctors first need to rule out more common conditions. In addition to taking a thorough medical history, a doctor will rely on imaging technology such as X-rays and CT scans to arrive at a pleural mesothelioma diagnosis. To reach a definitive diagnosis, a biopsy will be performed.
When the mesothelial cells in the peritoneum become irritated and inflamed by trapped asbestos fibers, the peritoneum begins to thicken and fluid begins to build up. Eventually, mesothelioma tumors are formed, putting pressure on the internal organs of the abdomen and leading to the following peritoneal mesothelioma symptoms:
Only about 5 percent of mesothelioma patients are diagnosed with pericardial mesothelioma, which begins in the cells lining the heart. As a result of the extreme rarity of this form of the disease, not much is known about symptoms of pericardial mesothelioma, which may include:
Only roughly 1 percent of all mesothelioma diagnoses concern pericardial mesothelioma, which affects the cells that line the heart. Fewer than 40 percent of patients live more than 6 months after being diagnosed with pericardial mesothelioma.
Pericardial mesothelioma strikes the membranes that surround the heart and is the rarest form of this cancer, accounting for only about 1 percent of all known mesothelioma diagnoses. The number of men with pericardial mesothelioma is more than twice the number of women who have this disease, and the average pericardial mesothelioma patient is diagnosed between the ages of 50 and 70.
While it has long been widely accepted that the cause of mesothelioma is exposure to asbestos, the exact causal link between pericardial mesothelioma and asbestos is still not fully understood because doctors and scientists have had so few cases to study.
As with other forms of mesothelioma, the first step in diagnosing pericardial mesothelioma is to take a thorough medical history. This is often followed by tests conducted with imaging technology such as X-rays, CT scans, and MRIs. Finally, a biopsy to test for cancer cells in the fluid or tissue of the pericardium is needed to arrive at a diagnosis of pericardial mesothelioma.
When asbestos fibers become lodged in the pericardium, or the membranes that surround the heart, they can eventually cause the pericardial cells to mutate and become cancerous. This causes the pericardial membranes to become thicker and leads to the development of tumors. This, in turn, can lead to a buildup of fluid around the heart, putting pressure on the heart that causes pericardial mesothelioma symptoms such as:
Because so few people are diagnosed with pericardial mesothelioma and because symptoms of this disease often don’t present until the cancer is well-advanced, up to 90 percent of pericardial mesothelioma diagnoses are made post-mortem.