Hearing a diagnosis of lung cancer is difficult and overwhelming. But it’s important to know not all lung cancers are the same. A stage 0 or stage 1 (I) lung cancer is very different than stage 3 (III) lung cancer or stage 4 (IV) lung cancer, also known as metastatic lung cancer. Your doctor will determine your treatment plan according to these lung cancer stages. There are also different types of lung cancer, primarily: non-small cell lung cancer, small cell lung cancer, and lung carcinoid tumor. These three types of cancer all start in your lung but they act differently. Your medical team will determine the type of lung cancer by looking at a sample of the cancer cells under a microscope. Non-Small Cell Lung Cancer Non-small cell lung cancer, or NSCLC is the most common type of lung cancer—accounting for more than 8 of every 10 lung cancers. There are five possible stages, numbered with Roman numerals. Your doctor will determine the stage of your cancer by its size, its location, and whether it has spread to lymph nodes or to areas outside your lung. Stage 0 is cancer that is in just the top layer of cells. It has not spread at all. Stage I cancer is smaller than 5 centimeters (cm). It has not spread to any lymph nodes. Stage II cancer has variations. It may be smaller than 7 cm and spread to a lymph node in the lung or grown into certain parts of the lung. Or, it may be larger than 7 cm but not spread to the lymph nodes. Stage III cancer can be different sizes. The cancer may be very near the lungs, like in the heart or esophagus. Or, there may be cancer in different parts of the same lobe of a lung or different lobes of the same lung. Cancer that has spread to lymph nodes outside of the lung is also stage III. Stage IV cancer has spread to other parts of the body, away from the lung. In medical terms, it has metastasized. Surgery alone may be the treatment for Stage 0 cancer. Standard treatment for stage I is surgery with or without cancer drugs (chemotherapy) or X-ray treatments (radiation therapy). A combination of surgery, chemotherapy and radiation may be the treatment for stages II-IV. Small Cell Lung Cancer Small cell lung cancer, or SCLC, spreads easier than non-small cell lung cancer. Fewer than 2 of every 10 lung cancers are small cell. Most doctors use a two-stage system to describe the status of small cell lung cancer: Limited stage. These cancers are on one side of the chest. Common treatment of limited stage small cell lung cancer is a combination of chemotherapy and radiation. Extensive stage. These cancers have spread across to the other lung or to distant parts of the body. Doctors treat this stage of small cell lung cancer with chemotherapy alone. Lung Carcinoid Tumor Lung carcinoid tumors have the highest chance for cure because they rarely spread. Less than 1 of every 10 lung cancers is a carcinoid tumor. Most doctors who treat lung cancer use only two stages to describe lung carcinoid tumors: Resectable stage. Surgery may be done to remove the cancer at this stage. Surgery alone may cure it. Unresectable stage. Surgery cannot completely remove these cancers. Chemotherapy and radiation are the usual treatment. The Importance of Diagnosing Lung Cancer Stages and Types The type and stage of lung cancer affect the type of treatment you will need. For instance, some newer lung cancer treatments are an option for non-small cell but not the small cell type of lung cancer. With a firm handle on the terminology for lung cancer type and stage, you’ll be prepared to talk with your doctor about the best options for treating your cancer.