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Lung Cancer Diagnosis
Learn about how your doctor can diagnose and treat lung cancer.

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Doctors divide lung cancer into two main types based on how the cancer cells look under a microscope. The two types are small-cell lung cancer and non-small cell lung cancer, which is more common. According to the American Lung Association, lung cancer is the leading cause of cancer deaths for both men and women in the United States.

If you think you have the symptoms of lung cancer, see your doctor immediately. Your doctor will evaluate your medical history, assess any risk factors you have, and perform a physical exam. Your doctor may then recommend additional testing if necessary.

Lung cancer testing can be invasive and can put people at an unnecessary risk. However, since people don’t usually exhibit symptoms until the disease has advanced, screening for it can help detect it early on, when it has a higher chance of curative treatment. Generally, your doctor will recommend a screening test only if they’ve found a reason to believe you might have it.

Diagnosing lung cancer

Physical exam

Your doctor will check your vital signs like oxygen saturation, heart rate, and blood pressure, listen to your breathing, and check for a swollen liver or lymph nodes. They may send you for additional testing if they find anything abnormal or questionable.

CT scan

A CT scan is an X-ray that takes several internal pictures as it rotates around your body, providing a more detailed image of your internal organs. It can help your doctor identify early cancers or tumors better than standard X-rays.


A thin, lighted tube called a bronchoscope will be inserted through your mouth or nose and down into your lungs to examine the bronchi and lungs. They may take a cell sample for examination.

Sputum cytology

Sputum, or phlegm, is a thick fluid you cough up from your lungs. Your doctor will send a sputum sample to a lab for microscopic examination for any cancer cells or infectious organisms like bacteria.

Lung biopsy

Imaging tests can help your doctor detect masses and tumors. Some tumors can have characteristics that are suspicious, but radiologists can’t be certain if they’re benign or malignant. Only a biopsy can help your doctor determine if suspicious lung lesions are cancerous. A biopsy will also help them determine the type of cancer and help guide treatment. Several methods of lung biopsy include the following:

  • During a thoracentesis, your doctor inserts a long needle to take a sample of fluid, called pleural effusion, between the layers of tissue lining your lung.
  • During a fine needle aspiration, your doctor uses a thin needle to take cells from your lungs or lymph nodes.
  • A core biopsy is similar to a fine needle aspiration. Your doctor uses a needle to take a larger sample called a “core.”
  • During a thoracoscopy, your doctor makes small incisions in your chest and back to examine lung tissue with a thin tube.
  • During a mediastinoscopy, your doctor inserts a thin, lighted tube through a small incision at the top of your breastbone to visualize and take tissue and lymph node samples.
  • During an endobronchial ultrasound, your doctor uses sound waves to guide a bronchoscope down your trachea or “windpipe” to look for tumors and photograph them if they’re present. They’ll also take samples from the areas in question.
  • During a thoracotomy, your surgeon makes a long incision in your chest to remove lymph node tissue and other tissue for examination.

Testing for the spread of lung cancer

Often, doctors use a CT scan as an initial imaging test. It involves the injection of contrast dye into the vein. CT gives your doctor a picture of your lungs and other organs where the cancer may have spread like your liver and adrenal glands. Doctors also often use CT to guide biopsy needles.

Other tests may be necessary to determine if and where cancer has spread, or metastasized, in the body:

  • Doctors may order an MRI when they suspect lung cancer may have spread to the brain or spinal cord.
  • A positron-emission tomography scan involves the injection of a radioactive drug, or tracer, which will collect in cancer cells, allowing your doctor to see the areas with cancer.
  • Doctors only order bone scans when they suspect cancer has spread to the bones. It involves injecting radioactive material into your vein, which builds up in abnormal or cancerous areas of the bone. They can then see it on imaging.

Stages of lung cancer

The stage of lung cancer describes the progression or extent of the cancer. If you receive a lung cancer diagnosis, the stage will help your doctor come up with a treatment for you. Staging doesn’t solely indicate the course and outcome of your lung cancer. Your outlook depends on your:

  • overall health and performance status
  • strength
  • other health conditions
  • response to treatment

Lung cancer is mainly classified as either small-cell or non-small cell lung cancer. Non-small cancer is more common.

Stages of small-cell lung cancer

Small-cell lung cancer occurs in two stages called “limited” and “extensive.”

The limited stage is confined to the chest and is usually in one lung and neighboring lymph nodes. Standard treatments include chemotherapy and radiation therapy.

The extensive stage involves both lungs and other parts of the body. Doctors usually treat this stage with chemotherapy and supportive care. If you have this type of lung cancer, you may want to see if you're a candidate for a clinical trial designed to evaluate the efficacy and safety of new drugs.

Stages of non-small cell lung cancer

  • In the occult stage, lung cancer cells are in sputum or in a sample collected during a test but no sign of a tumor in the lungs is present.
  • In stage 0, cancer cells are in the innermost lining of the lung only and the cancer isn’t invasive
  • In stage 1A, cancer is in the innermost lining of the lungs and deeper lung tissue. Also, the tumor is no more than 3 centimeters (cm) across and hasn’t invaded the bronchus or lymph nodes.
  • In stage 1B, the cancer has grown larger and deeper into the lung tissue, through the lung and into the pleura, is more than 3 cm in diameter, or has grown into the main bronchus but hasn’t yet invaded the lymph nodes. Surgery and sometimes chemotherapy are treatment options for lung cancers in stage 1A and 1B.
  • In stage 2A, cancer is less than 3 cm in diameter but has spread to the lymph nodes on the same side of the chest as the tumor.
  • In stage 2B, the cancer has grown into the chest wall, main bronchus, pleura, diaphragm, or heart tissue, is more than 3 cm in diameter, and may also have spread to the lymph nodes.
  • In stage 3A, the cancer has spread to the lymph nodes in the center of the chest and on the same side as the tumor, and the tumor is any size. Treatment for this stage may involve a combination of chemotherapy and radiation.
  • In stage 3B, the cancer has invaded the lymph nodes on the opposite side of the chest, the neck, and possibly the heart, major blood vessels, or esophagus, and the tumor is any size. Treatment for this stage involves chemotherapy and sometimes radiation
  • In stage 4, the lung cancer has spread to other areas of the body, likely the adrenal glands, liver, bones, and brain. Treatment for this stage involves chemotherapy, supportive, or comfort, care, and possibly a clinical trial if you’re a candidate and you choose to participate.

What is the outlook?

See your doctor immediately if you suspect you may have lung cancer. Many tests are available to confirm a diagnosis and to identify what stage the cancer is at if you do have cancer. Detecting cancer early on can help your doctor treat the cancer at an earlier stage and more effectively. Whatever stage the cancer is, treatment is available. 

Written by: The Healthline Editorial Team
Edited by:
Medically Reviewed by: [Ljava.lang.Object;@1caa8b7
Published: Oct 2, 2014
Published By: Healthline Networks, Inc.
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