When you inhale, the lungs transfer oxygen from the air to your blood. They also take carbon dioxide from your blood and get rid of it when you exhale. Lung Cancer is a disease caused by the unchecked growth and spread of some cells from the lungs.

There are two major types of lung cancer: Non-small cell lung cancer and Small cell lung cancer. Test for detecting possible lung cancer include both non-invasive test and invasive test. Non-invasive tests include: chest x-rays, CT scans and PET scans.

Invasive tests include: Bronchoscopy, Endobronchial ultrasound, Thoracentesis, Biomarker testing, Fine-needle aspiration, Core-needle biopsy and Surgical-lung biopsy. The doctor can remove a small sample of the lung tissue where cancer is suspected to check for cancer. A pathologist studies this biopsy sample under a microscope. If there is cancer, tiny amounts of the tissue are tested further for specific features that will identify the exact type of cancer present.

Lung cancer staging is a system that describes the overall size and spread of the main tumor. Doctors need staging information to plan the patient’s treatment. Lung cancer is classified into several stages. The higher the stage, the more advanced the spread of the disease.

Stage 0: In stage 0, the cancer is only in the top layer of the cells lining the lungs air passages. This is also called Carcinoma-in-situ.

Stage 1: In stage 1, the cancer is small and is only in 1 lobe of the lung and nowhere else.

Stage 2A: In stage 2A, the cancer is in one lung and the main tumor is small; less than 3 centimeters or 3 – 5 centimeters wide, and has spread to nearby lymph nodes. Stage 2A can also mean that the cancer is in one lung and the main tumor is slightly bigger (5-7 cm wide), but hasn’t spread to lymph nodes or elsewhere.

Stage 2B: The cancer is in one lung and the main tumor is approximately 5-7 cm wide, and has spread to nearby lymph nodes but not elsewhere. Stage 2B can also mean that the main tumor is wider than 7cm and has not spread to lymph nodes or elsewhere.

Stage 3A: The cancer has spread to lymph nodes along the trachea on the same side as the main tumor.

Stage 3B: The cancer has spread to the lymph nodes along the trachea opposite the main tumor.

Stage 4: The cancer has spread to the other lung as well as lymph nodes outside the lungs. Small lumps or nodules may appear in the lining of the lung.