What is the Difference Between Lung Cancer and Mesothelioma?

Mesothelioma defined

Many people ask this question, to which the answer is both simple and complex. The simple answer is that mesothelioma is a cancer of the mesothelium, the lining or membrane, around an organ, such as a lung, abdomen, or the heart. This mesothelium has specific names based upon the organ that it encases. The mesothelial lining around the lung is called the pleura, and has two layers that glide on a layer of fluid. The inner layer lines the lung tissue and the outer layer lines the chest wall. The fluid layer between the two lubricates the layers, allowing the lungs to expand and contract as the pleural layers can glide against each other without friction.

Lung cancer

Lung cancer involves the lung tissue and airways, which is contained entirely within the pleural lining and does not involve the pleura. Where other organs are involved the mesothelial lining has other names, such as peritoneum for the mesothelial lining of the peritoneum (abdominal cavity), and pericardium for the lining around the heart.

Mesothelioma causes

Mesothelioma is caused by inhaling asbestos fibers in most cases, which work their way through the softer lung tissue to the mesothelial lining (the pleura) and lodge in that membrane. It can take as much as 50 years for the fibers to cause symptoms of cancer, but some cases are diagnosable in as few as 10 or 20 years. Obviously, it’s a slowly developing process, and one whose cause isn’t always easy to identify due to the length of time between exposure and symptoms.

Mesothelioma exposure

Most people who develop mesothelioma were exposed to asbestos particles on-the-job, which they either inhaled or swallowed. Family members were exposed to the clothing, hair, or skin of workers who came home covered in fibers. Women who contacted these clothes, especially those who shook them out before washing them, or family members who greeted and hugged the worker before he had a chance to bathe were also exposed to the fibers.

In addition, community members were frequently exposed to fibers as dust from the mines, or processing plants that used asbestos released fibers into the air, which in turn could rain out on nearby communities.

Asbestos lung cancer

As rare as mesothelioma is, asbestos lung cancer is rarer, yet. If lung cancer results from pleural mesothelioma, it is usually because the cancer has metastasized and spread throughout the body. Asbestos lung cancer usually develops from fibers that lodged in the lining of the airways, bronchioles (small airways) or alveoli, the terminal sacs where oxygen enters the bloodstream. Asbestos fibers are massaged through the soft lung tissue and rarely lodge there. Instead, they lodge in the lining of the lungs where they remain causing a chronic irritation in the lining rather than the lung tissue itself. Those that lodge in the lung tissue usually become trapped by scar tissue and cause asbestosis, a restrictive fibrotic disease of the lungs.