Lung cancer starts in the lungs, which are two organs in your chest that help you breathe. The National Cancer Institute estimates that in 2009, over 219,000 new cases of lung cancer were diagnosed in the United States. There are different kinds of lung cancer that are classified according to the characteristics of the cancer cells under the microscope.
Small Cell Lung Cancer
Approximately 10 to 15 percent of diagnosed lung cancers are small cell lung cancers (SCLC), according to the American Cancer Society. As the name suggests, the cancer cells are small cells; other names for this kind of lung cancer includes oat cell cancer, oat cell carcinoma and small cell undifferentiated carcinoma. Cigarette smoking is the major risk factor for this kind of lung cancer, as well as secondhand smoke exposure. SCLC grows and spreads quickly to other organs, including the bones, brain and liver. Symptoms of SCLC include face and neck swelling, appetite loss, wheezing, persistent cough, chest pain and shortness of breath.
Non-small Cell Lung Cancer
Another major type of lung cancer is non-small cell lung cancer (NSCLC), and this comprises the majority of lung cancer diagnoses, making up 85 to 90 percent of cases. There are three sub-types of NSCLC: squamous cell carcinoma, which is typically a result of smoking cigarettes; adenocarcinoma; and large-cell or undifferentiated carcinoma. Smoking cigarettes is a risk factor for NSCLC, but other risk factors include asbestos or radon exposure, previous radiation therapy to the chest, and secondhand smoke exposure. The National Cancer Institute lists symptoms of NSCLC as including a persistent, lingering cough; chest discomfort; blood in any mucus that you cough up and difficulty breathing.
Carcinoid Tumors
Although SCLC and NSCLC are the two major types of lung cancers, other kinds of tumors can start in the lungs, including carcinoid tumors. Carcinoid tumors make up five percent or less of lung cancer diagnoses, and are typically slow-growing and cured with surgery. Even when carcinoid tumors spread, they tend to have a better prognosis than the other two kinds of lung cancer, according to the American Cancer Society.
