Early stage lung cancer often does not have symptoms. When symptoms do appear they can easily be mistaken for common respiratory illnesses like bronchitis or pneumonia. Because of this, many cases are diagnosed at an advanced stage.
Patients at high risk for lung cancer, especially those with a history of smoking, should undergo regular screenings in order to catch the disease at its early stages, when there is a better chance of cure.
If you have symptoms that signal lung cancer, your doctor will ask you questions about your medical, smoking and family history and whether you have been around certain chemicals or substances. Your doctor will likely also perform a physical exam to assess your lung function and overall health. This may involve listening to your lung sounds and performing blood tests. No one blood test can detect lung cancer. However, blood tests can give clues about the root cause of your symptoms. They may be used to rule out infection or to determine if other organ systems are being impacted. Additionally, if you have a productive cough, your doctor might look at a sample of your sputum (the mucus produced by your respiratory tract) under a microscope to see if cancer cells are present. This is called sputum cytology.
You will then undergo an imaging exam, typically a chest X-ray. If the image shows a lung mass or other area of concern, the doctor may order other more detailed scans. These may include a CT scan or PET scan. In a CT scan, an x-ray machine takes pictures from several different angles, creating a more detailed picture of the lungs. A PET scan can show areas of high cell activity and division, an indicator of cancer. These and other imaging tests may also be used to determine whether and how far the cancer has spread. For more information on these imaging exams, visit our Diagnostic Imaging Procedures page.
If the findings on the imaging scans indicate cancer, the doctor will request that tissue or fluid be removed from the lung and examined by microscope. The act of obtaining a tissue or fluid sample is called a biopsy. There are several ways doctors can perform biopsies of lung tumors:
- Bronchoscopy: A thin flexible tube with a tiny camera is inserted through the nose or mouth and down into the lungs to obtain a small tissue sample (biopsy). This is usually performed under mild sedation.
- Needle biopsy: Guided by a CT scanner, your doctor will insert a needle through the skin under local anesthesia to acquire a tumor sample
- Fine needle aspiration (FNA): A very small needle is placed into the tumor. Suction is used to remove a small amount of tissue.
- Thoracentesis: Fluid from around the lungs is drawn out with a needle and tested for cancer cells
- Endobronchial Ultrasound (EBUS): a bronchoscope with an attached ultrasound device is used to check for lung cancer inside nearby chest lymph nodes. EBUS is often performed at the same time as a bronchoscopy and requires general anesthesia.
- Video-assisted thoracoscopic surgery (VATS): This minimally invasive surgical procedure uses a small camera to help retrieve tumor samples that are otherwise difficult to access. VATS requires a general anesthetic and is performed in the operating room by a thoracic surgeon.
If you are diagnosed with lung cancer, your doctor will determine the stage (or extent) of the disease. The various stages classify cancer by how far and to which parts of the body it has spread. Staging helps the doctor plan the best treatment for you. As part of staging, you may undergo a PET-CT scan and, for most cases, an MRI of the brain to check for signs of cancer spread to other organs. Once the staging classification is determined, it stays the same even if treatment works or cancer spreads.
Staging is often the most important part of your treatment. If the cancer is staged improperly, you may not receive the right treatment.
The following are the lung cancer staging systems of the National Cancer Institute.
Non-small cell lung cancer stages
Occult (hidden) stage
In the occult (hidden) stage, cancer cannot be seen by imaging or bronchoscopy. Cancer cells are found in sputum or bronchial washings (a sample of cells taken from inside the airways that lead to the lungs). Cancer may have spread to other parts of the body.
In stage 0, abnormal cells are found in the lining of the airways. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 may be adenocarcinoma in situ (AIS) or squamous cell carcinoma in situ (SCIS).
In stage I, cancer has formed into a distinct tumor that measures no more than 5 centimeters. At this stage, the tumor has not spread to nearby lymph nodes or surrounding tissues. However, part of the lung or the whole lung may collapse or develop pneumonitis.
Stage II lung cancer is characterized by a tumor measuring 5 centimeters or less that may have spread to nearby lymph nodes. Stage II cancer can also be characterized by a tumor that measures less than 7 centimeters but that has not spread to nearby lymph nodes. At this stage, the cancer cells may have spread to other airways, such as bronchus, or the membrane lining the lungs. However, the cancer has not spread beyone the chest cavity.
In stage III, the cancer is still confined to the chest and surrounding areas, but the tumors tend to be larger and more invasive. It is also common for there to be one or more distinct tumors present in the lungs. Additionally, the cancer is likely to have spread to nearby lymph nodes and the surrounding tissue in the chest. This may include the diaphragm, the membranes lining the lungs or heart, or the nerves that control the voice box (larynx).
Stage IV cancer, also called metastatic lung cancer, is the most severe. It is characterized by the spread of cancer to distant lymph nodes and organs like the kidneys, brain, liver or bones.
Small cell lung cancer stages
Limited-Stage Small Cell Lung Cancer
In the limited-stage, cancer is in the lung where it started and may have spread to the area between the lungs or to the lymph nodes above the collarbone.
Extensive-Stage Small Cell Lung Cancer
In the extensive-stage, cancer has spread beyond the lung or the area between the lungs or the lymph nodes above the collarbone to other places in the body.
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