Pleural mesothelioma and lung cancer are not the same, although they are both serious diseases. Some treatments may be similar, but not alike.
Pleural mesothelioma is a cancer that originates in the pleura or lining of the lung . Lung cancer originates inside the lung itself, although the pleura may become involved as the disease progresses. It is not unusual that a biopsy be recommended when the doctor is weighing the possibility of one diagnosis versus the other.
Mesothelioma is a rare cancer with approximately 2,500 total diagnoses (US) per year, of which 70% are pleural mesotheliomas. As of the latest current statistics (2005), 107,416 men and 89,271 women were diagnosed with lung cancer during the year in the United States. Of all types of cancer, lung cancer kills the higher number of people.
Mesothelioma is caused by exposure to asbestos, and has no relationship to smoking. Lung cancers are most often associated with a smoking history, although asbestos exposure may be a contributing factor in some cases. The risk of lung cancer is greatly increased by persons who have combined risk factors.
Lung cancers are divided into two groups:
- Small Cell Lung Cancer (SCLC)
Small cell lung cancers comprise about 15% of all lung cancers diagnosed, and often begin in the bronchi near the center of the chest. This type of cancer is almost always caused by smoking.
- Non-small Cell Lung Cancer (NSCLC)
Non-small cell lung cancers comprise about 85% of all lung cancers diagnosed. There are 3 sub-types of non-small lung cancers: adenocarcinoma, usually found in the outer part of the lung; large-cell, which can start in any part of the lung; and squamous cell, which tends to be located near the bronchus, and is also linked to smoking.
Distinguishing between Adenocarcinoma and Mesothelioma
Adenocarcinoma is when the cancer starts in a gland or glandular tissue. There are different types; one is lung adenocarcinoma which is a form of lung cancer (and indeed the most common form among non-smokers.) Lung adenocarcinoma is often called non-small cell lung cancer.
One indication that can be used to tell the two apart is a blood component called carcinoembryonic antigen (CEA) which is elevated for people with adenocarcinoma but normal for people with mesothelioma. Hyaluronic acid is also found in pleural effusions of mesothelioma sufferers, and its presence can be a clue as to the presence of the disease. Another marker is called CA-125.
If you have any doubt as to your diagnosis, always consult with your doctor.