Your doctor will start by taking your health history. He or she will ask about your smoking habits and whether you live with a smoker. Your doctor also will ask whether you may have been exposed to asbestos or other cancer-causing agents at work.
Next, he or she will order imaging tests to check your lungs for masses. In most cases, a chest x-ray will be done first. If the x-ray shows anything suspicious, a CT scan will be done. As the scanner moves around you, it takes many pictures. A computer then combines the images. This creates a more detailed image of the lungs, allowing doctors to confirm the size and location of a mass or tumor.
You may also have a magnetic resonance imaging (MRI) scan or a positron emission tomography (PET) scan. MRI scans provide detailed pictures of the body's organs, but they use radio waves and magnets to create the images, not x-rays. PET scans look at the function of tissue rather than anatomy. Lung cancer tends to show intense metabolic activity on a PET scan. Some medical centers offer combined PET-CT scanning.
If cancer is suspected based on these images, more tests will be done to make the diagnosis, determine the type of cancer, and see if it has spread. These tests may include the following:
Sputum sample — Coughed-up mucus is checked for cancer cells.
Biopsy — A sample of abnormal lung tissue is removed and examined under a microscope in a laboratory. The tissue is often obtained during a bronchoscopy. However, surgery may be necessary to expose the suspicious area.
Bronchoscopy — During this procedure, a tube-like instrument is passed down the throat and into the lungs. A camera on the end of the tube allows doctors to look for cancer and to remove a small piece of tissue for a biopsy.
Mediastinoscopy — In this procedure, a tube-like instrument is used to biopsy lymph nodes or masses between the lungs. (This area is called the mediastinum.) A biopsy obtained this way can diagnose the type of lung cancer and determine whether the cancer has spread to lymph nodes.
Fine-needle aspiration — With a CT scan, a suspicious area can be identified. A tiny needle is then inserted into that part of the lung. The needle removes a bit of tissue for examination in a laboratory. The type of cancer can then be diagnosed.
Thoracentesis — If there is fluid build-up in the chest, it can be drained with a sterile needle. The fluid is then checked for cancer cells.
VATS (video-assisted thoracoscopy) — In this procedure, a surgeon inserts a flexible tube with a video camera on the end into the chest through an incision. He or she can then look for cancer in the space between the lungs and the chest wall. Abnormal lung tissue can also be removed.
CT, PET, and bone scans — These imaging tests can detect lung cancer that has spread to the brain, bones, or other parts of the body.
After the cancer has been diagnosed, it is assigned a "stage." The stage indicates the tumor's size and how far it has spread. Stages I through III are further divided into "A" and "B" categories. Stage I tumors are small and have not invaded surrounding tissues. Stage II and III tumors have invaded surrounding tissues and/or organs and have spread to lymph nodes. Stage IV tumors have spread beyond the chest.