Exams and Tests

To determine whether lung cancer may be causing your respiratory symptoms, your health professional will evaluate your:

• Medical history, including your smoking history and any symptoms you have now.
• Exposure to environmental and work substances.
• Family history of cancer.

Initial exams and tests for suspected lung cancer include:

• Medical history to determine your risk factors for developing lung cancer.
• Physical examination to find any lung problems or swollen lymph nodes.
• Chest X-ray to look for any abnormalities that may be causing your symptoms, such as pneumonia or a lung mass (tumor).
• Complete blood count (CBC) to see whether you have abnormal values of red blood cells, white blood cells, or platelets.
• Calcium, creatinine, alkaline phosphatase, and lactic acid dehydrogenase to determine electrolyte and liver function. These tests are likely to have abnormal values if cancer is present and has spread to other tissue or body organs.

If your medical history, physical examination, or chest X-ray suggest that lung cancer is present, your health professional may recommend other tests, such as:

• CT scan of the lungs, sometimes with transthoracic needle aspiration biopsy (TNAB) of a lung nodule. A needle biopsy uses a needle inserted through the chest wall to remove a sample of lung tissue (biopsy). This usually is done if the abnormal lung tissue is located close to the chest wall. Imaging procedures such as ultrasound or fluoroscopy may also be used to help guide the needle to the right spot.
• Sputum cytology to evaluate the type of any abnormal cells that are present in your mucus.
• Thoracentesis to take a sample of the fluid around your lungs to evaluate the type of any abnormal cells. Thoracentesis is done if you have a large collection of fluid around your lung (pleural effusion). Thoracentesis is sometimes used to find out why you have fluid collecting around your lung. Other times it is just to remove the fluid and make it easier for you to breathe..
• Bronchoscopy to take a biopsy of cells from your airway.
• Lung biopsy to evaluate the type of any abnormal cells.
• Video-assisted thoracoscopy (VATS) to take a biopsy of lung tissue through a small incision between two ribs with the aid of a thin, lighted tube (videoscope) and small surgical instruments.

After the type of lung cancer has been diagnosed, testing is done to determine whether the cancer has spread (metastasized) to other organs in your body and to determine the stage of the cancer. Treatment of lung cancer is based on the stage of the cancer. Tests used to determine whether the cancer has spread may include:

• Mediastinoscopy to take biopsies of lymph nodes to determine whether the cancer has spread to the chest behind the breastbone (mediastinum).
• Endoscopic ultrasound is sometimes done after a mediastinoscopy. In this test, a small ultrasound probe at the end of the endoscope is placed down the throat to the chest area. The ultrasound can help detect cancer behind the breast bone or in lymph nodes in the area. When endoscopic ultrasound and mediastinoscopy are both done, they may be able to determine the stage of lung cancer better than mediastinoscopy alone.⁸ Endoscopic ultrasound is not yet widely available.
• CT scan of the brain, neck, abdomen, or pelvis to determine whether the cancer has spread to these areas.
• MRI of the brain to determine whether the cancer has spread to the brain.
• Positron emission tomography (PET). PET scanning can help determine whether a lung mass (tumor) or enlarged lymph node is cancerous. PET may help determine whether surgery is a treatment option. PET scanning may also be used after treatment to see how well the treatment worked. PET scanning can be used to look for areas of the liver, adrenal gland, or bone that may show where lung cancer has spread.
• Bone scan to determine whether the cancer has spread to the bones.

An MRI of the spine may be done if there is concern that the lung cancer has already spread to the spine. An MRI of the chest may also be done, but a chest CT scan is used most often to determine whether the cancer has spread in the chest.

Lung function studies, including a lung scan (ventilation and perfusion scans, V/Q scan), may be done if surgery to remove cancer in all or part of a lung is being considered. A person who has very poor lung function may not be a good candidate for surgery.

If small cell lung cancer is diagnosed, additional testing may include a bone marrow aspiration and biopsy.

Early Detection

Several studies have examined the usefulness of chest X-rays, sputum cytologies, or spiral CT to screen for lung cancer in people who do not have symptoms. Although these tests can sometimes diagnose early lung cancer, they have not been proven to affect the long-term outcome (prognosis) of lung cancer. Currently no medical professional organizations recommend routine screening for lung cancer.^{9, 10} Experts continue to study the benefits of screening tests.

Screening tests may aid in the early diagnosis of lung cancer, but the tests can also show abnormal findings, such as nodules, that are not cancer (false-positives). The finding of a solitary pulmonary nodule (SPN) on a chest X-ray does not always mean that cancer is present. Certain tests can help health professionals determine whether an SPN is noncancerous (benign) or cancerous (malignant). If cancer is suspected and the tissue is located close to the chest wall, a needle biopsy is recommended to confirm or rule out the presence of cancer. A needle biopsy uses a long needle inserted through the chest wall to remove a sample of lung tissue. Imaging procedures such as CT scan, ultrasound, or fluoroscopy usually are used to help guide the needle to the right spot.