Your doctor will likely ask whether you smoke and whether you have had contact with lung irritants, like air pollution, dust, secondhand smoke, or chemical fumes. If your doctor suspects you might have lung cancer, he or she might also perform tests to diagnose it:
- Imaging tests: X-ray or computed tomography (CT) scans are scans that provide images of the lungs. Doctors can visually inspect these images for signs of any abnormal mass. CT scans provide more detail and can show small lesions on the lungs that are not visible on an X-ray image.
- Lung tissue analysis: your doctor may wish to examine a small amount of your lung tissue in a laboratory. This is called a biopsy. Your doctor may obtain the tissue sample using a bronchoscope, a small flexible tube that passes into your lungs through your nose or mouth and collects a very small tissue sample. Sometimes a needle can be directed into the lung from between the ribs in order to get a sample of tissue. Your doctor may also obtain a tissue sample in surgery, while you are under general anesthesia. It is possible to obtain a larger tissue sample surgically than using a bronchoscope or with a needle.
- Sputum cytology: if you produce sputum when you cough, your doctor can examine the sputum under a microscope. This sometimes will show the presence of lung cancer cells, but is not commonly done or as reliable as the other methods.
Once you are diagnosed with lung cancer, your doctor will determine the stage of the cancer. Describing cancer using stages expresses how advanced it is. The stage of your cancer also helps your doctor decide on the best treatment.
The stages of lung cancer are:
- Stage I: the cancer is only in the lung and has not spread to the lymph nodes. Any tumor is smaller than two inches in diameter.
- Stage II: the cancer may have spread to nearby lymph nodes. Any tumor in Stage II will be either larger than two inches in diameter, or smaller, but involving nearby structures, such as the diaphragm, chest wall, or the lining around the lungs.
- Stage III: the cancer may have spread through the lymph nodes and caused smaller tumors and cancer cells in lymph nodes farther away from the lungs. Any lung tumor at this stage is usually quite large and may have invaded or affected other organs or structures near the lungs.
- Stage IV: the cancer has spread past the lung where it began to either the other lung or other farther-away areas of the body.