Mesothelioma cancer is a type of cancer that develops in the thin tissue, or mesothelium, that lines the lungs, chest wall and abdomen. The mesothelium helps protect the organs by producing a lubricating fluid that lets them move against one another. Mesotheliomas start in the chest, abdomen, heart or testicles. Most begin in the chest, and are called pleural mesotheliomas.
Age is a risk factor for mesothelioma, with most people developing the disease later in life, but the major risk factor for this type of cancer is asbestos exposure. Researchers are working to learn more about which asbestos fibers cause cancer, how they cause it, and what levels may be considered safe.
Companies used asbestos until the government began regulating it in the 1970s. Workers more likely to have been exposed include industrial workers, sailors, shipyard workers, construction laborers and skilled tradesmen, and miners, among many others.
Mesothelioma is considered a rare disease. Around 3,000 people, most over the age of 65, are diagnosed with mesothelioma in the United States each year, according to the American Cancer Society. The disease is strongly associated with exposure to asbestos, a fibrous mineral used in construction materials for many years. People who have been exposed to asbestos may have inhaled tiny fibers that may remain in the lungs for 20 to 50 years. During this period of time, mesothelioma may slowly develop.
Exposure to asbestos is now declining and occurs much less often than it did in the past. But anyone with a history of asbestos exposure can still get a diagnosis of mesothelioma today. This cancer has a long latency period, not appearing for decades after exposure.
The Cause of Mesothelioma Cancer
The only known cause of this type of cancer is asbestos exposure.
Asbestos is a fiber that was once widely used in hundreds of building, industrial, commercial, and housing products and is still present in millions of U.S. workplaces and homes.
The risk of exposure to asbestos remains a very real danger and symptoms of malignant mesothelioma do not appear for at least 15 years after asbestos exposure.
For those who worked with or around asbestos products, airborne fibers can be inhaled or ingested, lodging themselves in the tissue lining the lung (known as the pleura), chest cavity, or abdominal cavity.
These fibers can stay in the body for decades before mesothelioma develops.
How Does Asbestos Cause Mesothelioma Cancer?
People who are exposed to asbestos typically inhale tiny fibers that stick in the pleura tissue lining the lungs and coating the chest wall.
These asbestos fibers can cause cellular changes, and may cause irritation and inflammation in the pleura for many years before malignant pleural mesothelioma develops.
In some cases, people ingest rather than inhale the microscopic asbestos fibers, which can then become lodged in the tissue lining the abdominal cavity and organs.
This can eventually cause peritoneal mesothelioma, also known as abdominal mesothelioma.
In rare cases, the asbestos fibers make their way to the tissue lining the heart or the testicles, resulting in pericardial or testicular mesothelioma.
How Dangerous Is Asbestos?
Asbestos poses a serious health hazard to anyone exposed to it.
Since the 1970s, the U.S. government has been working to reduce the use of asbestos-containing materials and has implemented asbestos safety precautions for workers who may come into contact with the deadly material. However, it is still not completely banned in the United States. And there is no safe level of exposure.
Asbestos exposure can lead to a number of serious diseases.
Is There a Test For Asbestos Exposure?
Although there are no screening tests yet, if you know or suspect that you have been exposed to asbestos, you should talk to your doctor about doing a chest X-ray once a year.
X-rays, CT scans, and MRIs can be used to help diagnose mesothelioma and other asbestos-related diseases early.
Also, cutting-edge blood tests (such as the MESOMARK blood test) have the potential to improve your chances of early detection.
Can Adenocarcinoma Be Caused By Asbestos?
Adenocarcinoma is a cancer that originates in the glandular cells. According to the National Cancer Institute, most cancers of the lung, prostate, colon, pancreas, and breast are adenocarcinomas. Inhalation of asbestos fibers can be a cause of adenocarcinoma in the lungs.
The Difference Between Mesothelioma and Asbestos
Asbestos refers to a group of six fibrous minerals that occur naturally in the environment.
These minerals have been used in many industrial and household products over the years. Asbestos is considered a dangerous carcinogen, which means it is a cause of cancer.
Types of Malignant Mesothelioma
Malignant mesothelioma is a cancer of the cells of the mesothelium. The mesothelium is a thin, double layer of tissue lining the chest cavity, abdominal cavity, and heart.
- Pleural mesothelioma is the most common type. It develops in the pleural tissue around the lungs.
- Peritoneal mesothelioma, which develops in the abdomen, is less common.
- One of the rarest types occurs in the tissue around the heart and is called pericardial mesothelioma.
- More than three-quarters of cases of mesothelioma are pleural.
- Exposure to asbestos is usually through inhalation of the fibers into the airways.
- Inhaled asbestos fibers lodge in the pleural tissue and cause damage.
- Symptoms include difficulty breathing, chest pains, coughing, and shortness of breath.
- This extremely rare form of mesothelioma accounts for just 1% of all cases.
- The primary tumor develops in the pericardium around the heart.
- Treating a cancer so close to the heart is extremely difficult.
- Symptoms include chest pain, difficulty breathing, heart palpitations, fatigue, and coughing.
- Peritoneal mesothelioma accounts for less than 20% of all cases.
- It occurs in the peritoneum in the abdominal cavity.
- Symptoms include abdominal pain, swelling or tenderness, and constipation or diarrhea.
- Peritoneal mesothelioma may be misdiagnosed as colitis or irritable bowel syndrome.
Mesothelioma types can also be organized by the kind of cells that make up the tumor.
- Epithelioid: This is the most common type and has the best prognosis and life expectancy.
- Sarcomatoid: Less common and more aggressive than the epithelioid type, these cells grow and spread rapidly. The prognosis is worse.
- Biphasic or Mixed: This type is a mix of epithelioid and sarcomatoid cells.
Signs and Symptoms of Mesothelioma Cancer
Symptoms of malignant pleural mesothelioma, the most common form of the asbestos cancer, often start out like other respiratory diseases such as the flu, pneumonia, or COPD.
However, anyone with a history of asbestos exposure should seek medical attention immediately if he or she exhibits these symptoms below:
- Shortness of breath
- Chest pain
- Pleural effusion (fluid on the lungs)
- Weight loss
- Persistent cough
- Loss of appetite
Treatment of Mesothelioma Cancer
Chemotherapy may be used to treat patients with advanced pleural mesothelioma and mesothelioma that cannot be surgically removed. For earlier-stage disease, chemotherapy may be used in combination with surgery and radiation therapy.
Immunotherapy may be used to treat certain types of mesothelioma. The U.S. Food and Drug Administration (FDA) has approved several types of immunotherapy drugs to treat the disease.
Radiation therapy may be used to destroy cancer cells that remain after surgery.
Surgery often depends on the type of mesothelioma and whether the cancer has spread. It may be used to help remove the cancer, or it may be used to lessen symptoms of the disease.
The FDA has approved targeted therapy drugs called anti-angiogenesis drugs that stop the production of new blood vessels in an effort to deprive the tumor of oxygen.
Side Effects of Mesothelioma Cancer Treatment
Mesothelioma patients may experience side effects, either from the disease or its treatments. The side effects may include fatigue, skin reactions, nausea and neuropathy.