This animation is from our new program http://www.YouandLungCancer.com and explains how healthy lungs function and how lung cancer can occur. Non-small cell lung cancer and small cell lung cancer are the two major types of lung cancer. Physicians use noninvasive tests and invasive tests to diagnose lung cancer. Noninvasive tests include Chest x-rays, and CT scans and PET scans. Invasive tests include Bronchoscopy; Endobronchial ultrasound; Thoracentesis; Biomarker testing; and Biopsies, such as Fine needle aspiration (or FNA), Core needle biopsy, and surgical lung biopsy. Physicians need lung cancer staging information to plan treatment. Lung cancer is classified into numerous stages – the higher the stage the more advanced the spread of the cancer and typically the more aggressive the treatment. In Stage 0 cancer it is only the top layers of cells in the lining of air passages in the lungs. This is the easiest stage to treat with highest survivorship. Stage IV lung cancer is the most difficult to treat, having spread to the other lung, the lymph nodes outside the lungs, and other parts of the body.