Lung Cancer Information -
Primary Lung Cancer, Secondary Lung Cancer
A Closer Look at Lung Cancer
Lung cancer is the deadliest type of malignant tumor, killing an average of three million people each year worldwide. Cigarette smoking is the biggest risk factor, accounting for an estimated 80% of all lung cancer cases (studies estimate that second-hand smoke is responsible for 3,000 lung cancer deaths each year).
Lung cancer originating in the lung tissue is defined as primary lung cancer, while cancer that originates elsewhere and migrates to the lungs during metastasis is defined as secondary lung cancer (the lung is one of the most common places for metastasis from tumors originating elsewhere in the body). Secondary lung cancer is a type of secondary lung disease.
Aside from primary and secondary classifications, there are two main types of lung cancer; small-cell lung cancer and non-small cell lung cancer.
Small-cell lung cancer: approximately 20% of lung cancer cases are small-cell carcinoma (also known as “oat cell carcinoma”). This type of lung cancer is most closely associated with cigarette smoking.
Non-small cell lung cancer: approximately 80% of lung cancer cases are non-small cell. The three non-small cell lung cancer subtypes include:
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Squamous cell carcinoma: this common form of lung cancer originates in the bronchi and is slow-spreading.
Adenocarcinoma: this type of lung cancer forms near the gas-exchanging surface of the lung. It is less often associated with cigarette smoking.
Large cell carcinoma: growing near the surface of the lung, large cell carcinoma is fast-growing and comprises 15% of all lung cancer cases.
Asbestos Lung Disease
Asbestos is carcinogenic, meaning that it can cause cancer when inhaled. There are a number of asbestos lung diseases that result from asbestos exposure, including:
- Malignant mesothelioma
- Asbestos lung cancer
- Asbestosis
Malignant mesothelioma is a relatively uncommon type of cancer most often associated with asbestos exposure. Although malignant mesothelioma can lead to secondary lung cancer, people are mistaken when labeling it mesothelioma lung cancer. Pleural mesothelioma is a cancer of the cavity surrounding the lungs, whereas lung cancer is a cancer of the lung tissue itself. Diagnosis of mesothelioma can occur anywhere from 30 to 40 years after asbestos exposure. The typical mesothelioma diagnosis results after the symptoms of mesothelioma manifest themselves (mesothelioma symptoms vary dependent on type).
People with malignant mesothelioma are at increased risk of developing secondary lung cancer; however, the secondary lung cancer is independent of the malignant mesothelioma.
Asbestos lung cancer results from asbestos exposure. Smokers exposed to asbestos increase there chances of developing lung cancer by 55 times. Asbestos lung cancer is a primary lung cancer (primary lung disease), not to be confused with pleural mesothelioma.
Asbestosis is a type of chronic inflammatory disease that causes fibrous scarring of the lung tissue. Although not as serious as the other asbestos lung diseases, asbestosis can lead to shortness of breath and chronic coughing. Asbestosis puts people at increased risk of developing lung cancer.