How Doctors Test for Lung Cancer

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Doctor Listening The Patient's Lungs

If you are a current or former smoker and are older than 55, your doctor may routinely screen you for lung cancer with an X-ray or CT scan. (A 2021 recommendation covers people ages 50 to 80 with a 20 pack-year smoking history.) For others, the journey to a lung cancer diagnosis may begin with a symptom, such as:

If your doctor suspects you might have lung cancer, you may receive imaging studies, lab work, and other specialized tests.

Imaging Tests for Lung Cancer

If you go to the doctor with symptoms that could indicate lung cancer, he or she will conduct a thorough examination and probably order some lab work. Then he or she probably will order some imaging tests to detect any tumors in your chest. Imaging tests for lung cancer include:

  • X-ray
  • Computed tomography (CT)
  • Magnetic resonance imaging (MRI)
  • Positron emission tomography (PET)

If your doctor identifies a mass in your lungs using any of these imaging tests, he or she will want to obtain a tissue sample to examine individual cells for cancerous changes.

Tests for Lung Cancer Diagnosis

In choosing a particular diagnostic procedure, your doctor will consider on the size and location of the suspected tumor. To obtain a tissue sample of the mass, your doctor may perform:

  • Bronchoscopy: In this procedure, performed under general anesthesia, your doctor will pass a flexible instrument down your throat and into your lungs to visually examine tissue and remove a sample of it.
  • Mediastinoscopy: For this procedure you’ll be given general anesthesia. Your doctor will make a small incision in your neck to pass instruments into your chest cavity to sample tissue from your lungs and lymph nodes.
  • Needle biopsy: Using visual guidance from a CT scanner or fluoroscopy machine, your doctor will guide a thin needle through the chest wall in order to sample cells from your tumor. You may be given a mild sedative to relax you during this procedure.
  • Thoracentesis: Sometimes lung cancer will cause fluid to seep into the space surrounding the lungs. In this case, your doctor may insert a needle through your skin to draw off some this fluid for examination. Only local anesthesia, to number the area, is needed for this procedure.
  • Sputum sample: Your doctor may ask you to collect samples of the material you cough up to see if it contains cancer cells.

After any of these procedures, a specially trained doctor (pathologist) will examine the tissue samples under a microscope. If the cells are abnormal, the pathologist will be able to identify the specific type of lung cancer you have:

  • Non-small cell, the most common type of lung cancer
  • Small-cell, a less-common lung cancer that tends to spread rapidly
  • Lung carcinoid tumor, an uncommon, slow-growing cancer

After Diagnosis: What Next?

As soon as your doctor has diagnosed lung cancer, he or she will “stage” your cancer. This process involves determining the size and extent of your tumor. Small lung cancer tumors that have not spread may be categorized as “Stage I,” while a large tumor with cells that have spread to other areas of the body may be classified as “Stage IV.” This stage number will help guide available treatment options based on outcomes of thousands of previous lung cancer patients with a similar tumor stage.

Once your cancer has been staged, you will be paired with a cancer doctor (oncologist) to develop a personalized plan for treating your lung cancer.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Feb 21
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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  2. How Is Non-Small Cell Lung Cancer Diagnosed? American Cancer Society.
  3. Staging of Lung Cancer [PDF]. American Thoracic Society.
  4. US Preventive Services Task Force. Screening for Lung Cancer : US Preventive Services Task Force Recommendation Statement . JAMA. 2021;325(10):962–970. doi:10.1001/jama.2021.1117