Lung cancer, diagnosed in 213,380 Americans in 2007, the Merck Manual states, occurs mostly in cigarette smokers and often has already spread, or metastasized by the time it's diagnosed. Like many cancers, different stages, determined by the spread of the cancer, define lung cancer. Symptoms, treatment and survival rates can vary depending on the stage of the cancer.
Types
Several different types of lung cancer exist, determined by the type of abnormal cells present. Non-small cell lung cancer comprises 85 to 87 percent of lung cancers, while small-cell lung cancer makes up the other 13 to 15 percent, Merck reports. Non-small cell stages range from 0 to stage IV. Small cell cancer, a much more aggressive cancer, includes limited-stage disease and extensive-stage disease, according to the National Cancer Institute. Around 60 percent of people already have extensive-stage disease at the time of diagnosis, the Merck Manual states.
Stages
Determinations for lung cancer can be difficult. Limited-stage small cell disease has not spread beyond the side of the lung where the cancer originated, the mediastinum or the lymph nodes above the clavicles. Extensive-stage disease has spread beyond these points and always includes metastasized cancers. Non-small cell stages begin with the presence of abnormal cells which may turn into cancer in stage 0 and advance through stage IV, where cells have metastasized to other areas or are found in the fluid around the lungs or heart, the National Cancer Institute explains. One or more tumors may be found in the lungs.
Diagnosis
Staging of lung cancers involves several methods of determining the spread of cancer cells. Testing methods for screening and diagnosis include x-ray, computed tomography or CT scan, magnetic resonance imaging or MRI, positron emission tomography or PET, and bone scans, MayoClinic.com explains.
Treatments
Treatments differ depending on the stage of cancer found. Typical treatment regimens for small-cell cancer include chemotherapy, radiation and sometime surgery in the limited-stage, and chemotherapy, enrollment in clinical trials for experimental drugs and supportive care to keep the person comfortable. Treatments for non-small cell lung cancer often start with surgery in stage I or II, sometimes combined with chemotherapy. Surgery may be used in stage III if the tumor is small enough to remove. More typically, chemotherapy and radiation are used. In stage IV, treatment consists of chemotherapy, targeted drug therapy, enrollment in clinical trials and supportive care, MayoClinic.com states.
Survival Rates
Survival rates for lung cancer are much higher if the cancer is diagnosed early. Overall, the five-year survival rate is around 10 percent, Healthcommunities.com reports. People under age 30 with tumors that can be completely removed have a survival rate of 85 percent, according to the same source. For specific stages, 50 percent of people survive from three to more than five years in stage I, between 20 and 24 months in stage II, 12 to 15 months in stage III and around eight months in stage IV. For small-cell cancer, 50 percent survive two to three years if diagnosed in the limited stage, and three to four months if diagnosed in the extensive stage.
