How Is Lung Cancer Diagnosed?
Medically reviewed by Archana Sharma, DO
A healthcare provider may use several diagnostic measures, including a physical exam and imaging tests, to check for lung cancer. Lung cancer will not show up in blood work, but your results can indicate signs of a possible health concern. These tests can help a healthcare provider understand your symptoms, the type of cancer you have, and the severity of your condition.
Lung cancer occurs when cells in the lungs grow out of control and become cancerous. As the condition progresses, the cancer cells can spread to the lymph nodes, brain, and other organs in the body. It's a good idea to get tested if you think you may be at risk for developing lung cancer or have symptoms. The disease can spread quickly.
A healthcare provider may consult with a team made up of a pulmonologist (who treats lung diseases) and an oncologist (who treats cancer) to rule out other conditions and provide you with an official diagnosis. Getting tested for lung cancer can be scary. Receiving an early diagnosis can help you get started on treatment sooner.
Types of Lung Cancer
There are two types of lung cancer: small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). A healthcare provider can determine what type you have through testing.
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Medical History and Physical Exam
A healthcare provider will start your appointment by learning about your medical history and performing a physical exam. This first step helps them understand your symptoms and look for potential signs of lung cancer.
A healthcare provider may ask:
Do you have a worsening cough?
Have you had trouble breathing?
Are you coughing up blood or losing weight without trying?
What other symptoms do you have?
How long have you been experiencing symptoms?
Does anyone in your family have lung cancer?
Do you currently smoke or have a personal history of tobacco use?
Have you had any recent respiratory (lung-related) infections?
It's also common for a healthcare provider to ask about your lifestyle habits, like diet and exercise. Exposure to toxins can also increase your risk of developing lung cancer, so they may want to learn about your occupation and place of work. Some workplaces can have elevated levels of radon, asbestos, or secondhand smoke in the air.
A healthcare provider will then perform a routine physical exam, which will likely include:
Checking your chest, stomach, and extremities (hands and feet) for pain, weakness, or swelling
Measuring your vital signs (e.g., temperature, heart rate, blood pressure)
Taking your temperature
Learning about your medical history and performing a physical exam are not enough to diagnose you with lung cancer. These steps can help a healthcare provider figure out how to move forward and order additional testing if needed.
Blood Tests
Blood tests alone cannot diagnose lung cancer. Blood work can help a healthcare provider get an overall sense of your general health, so it's standard practice to get blood tested. Your blood test will generally show a complete blood count (CBC). This test can point to any concerns in the number of white blood cells, red blood cells, platelets, and other cell types.
A healthcare provider can order blood chemistry tests for further evaluation if something in your blood tests doesn't look normal. A blood chemistry test examines the cells in your organs. This test can look at the function of your liver, kidneys, and other major organs. Abnormal test results can mean the cancer has spread to areas outside of the lungs.
If you receive a cancer diagnosis, you may be asked to come in for blood testing regularly. Routine blood tests can help a healthcare provider understand how your treatment is working and monitor your overall health status.
Imaging Tests
Imaging tests create detailed pictures of your lungs by using sound waves, magnetic fields, or X-rays. These tests can detect if you have cancer cells or a tumor, how far the cancer has spread, and whether or not treatment is working.
A healthcare provider may order one or more of the following imaging tests:
Type of Imaging Test | Description |
Bone scan | Determines if the cancer has spread to your bones |
Chest X-ray | Takes radiographic pictures to check the structure of the organs in the chest |
Computed tomography (CT) scan | Combines several X-ray images to show a more detailed visual of the lungs, potential tumors, and enlarged lymph nodes |
Uses magnets and radio waves to take images of the soft tissue in your chest to check if the cancer has spread to other organs | |
Positron emission tomography (PET) scan | Injects a safe radioactive material intravenously (with an IV) to look for chemical changes to your cells and organs |
Lab Testing
Blood and imaging tests can give a healthcare provider a better sense of your health. An official lung cancer diagnosis requires laboratory tests that look at your lung cells. There are several types of lab tests that a healthcare provider may use to make a lung cancer diagnosis and check to see how far the cancer has spread.
Tests for Diagnosis
A lab technician will perform tests by using a sample of your lung cells under a microscope. Some lab tests that a healthcare provider may order to confirm a lung cancer diagnosis include:
Biopsy: This uses a needle to take a sample of your lung tissue. A lab technician will then view the sample under a microscope to check for cancer cells.
Bronchoscopy: This looks at the inside of your lungs with a thin, flexible tube that is attached to a camera. A bronchoscopy checks for tumors or blockages in your airways.
Sputum cytology: A healthcare provider will ask you to cough up a sample of your sputum (mucus from your lungs) to check if your mucus contains cancer cells.
Thoracentesis: Some people may have pleural effusion, or fluid build-up around the lungs. A healthcare provider can perform this test by numbing the skin and inserting a small needle or catheter into the chest to drain a sample of fluid. A lab technician can test the fluid to determine what is causing the build-up.
Tests for Cancer Spread
If a healthcare provider finds cancer cells, they will likely order additional testing to see if the cancer has metastasized (spread). Lab tests can show where cancer cells have spread and help inform treatment options. These tests insert a thin tube attached to a tiny light and camera inside your body. This helps inspect cancer cells in different organs and structures.
A healthcare provider may order one or more of the following tests:
Endobronchial ultrasound: This procedure moves the tube down the neck to check for cancer cells around the breastbone and in between the lungs.
Endoscopic esophageal ultrasound: This ultrasound passes the tube down your throat to search nearby lymph nodes for cancer cells.
Mediastinoscopy or mediastinotomy: This exam puts the tube behind the breastbone to check for cancer cells in the mediastinum, which includes the heart, esophagus (throat), and trachea (windpipe).
Thoracoscopy: This test inserts the tube under your shoulder blades to check for cancer cells that have spread outside of the lungs and into the chest.
Lung Function Test
A healthcare provider may order a lung function test, or pulmonary function test (PFT), after they make a lung cancer diagnosis. A lung function test can show how well your lungs are working.
There are several types of lung function tests, but they all generally have the same instructions. You'll breathe in and out of a tube connected to a machine that measures your airflow.
This test tells a healthcare provider whether it's safe to have lung surgery. Surgery may be a treatment option, depending on the type of cancer you have. The lung function test informs how much of the lung a surgeon can remove, if needed, for your treatment plan.
Stages of Lung Cancer
A healthcare provider will determine what stage of lung cancer you are in if you receive a diagnosis of lung cancer. Staging is based on where your cancer cells are and the size of your tumor. Your cancer stage will inform treatment options.
The stages of cancer for SCLC and NSCLC are different. The stages of SCLC are:
Limited stage: Cancer cells are present in the lungs.
Extensive stage: Cancer cells have spread beyond the lungs into other lymph nodes and organs.
The stages of NSCLC are numbered and include:
Stage 0: Cancer cells are present in the lining of the lungs but have not spread to the lung tissue.
Stage 1: The cancer cells have developed into a small tumor, or less than 3 centimeters (cm).
Stage 2: The tumor is larger than 3 cm, and cancer cells have spread to nearby lymph nodes.
Stage 3: Cancer cells have spread to nearby organs in the chest.
Stage 4: The tumor can be any size, and cancer cells have spread to the lung tissue and nearby or distant organs.
Screening for Related Conditions
Lung cancer symptoms can sometimes mimic other conditions. A healthcare provider will also use testing to rule out other conditions, including:
Condition | Description |
Infection of the bronchial tubes in the lungs | |
Granuloma | Non-cancerous inflammation of the lungs |
Hamartoma | Non-cancerous growth of abnormal lung cells |
Pleural effusion (caused by other conditions) | Fluid build-up in and around the lungs |
Inflammation in one or both lungs caused by bacteria, fungi, or viruses | |
Pneumothorax | Air build-up between the outside of the lung and within the pleural cavity (the space between your lungs and chest cavity), which can cause the lungs to collapse partially or completely |
Tuberculosis | Bacterial infection in the lungs |
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A Quick Review
Lung cancer symptoms can vary depending on the type of cancer, the location, and the stage of cancer. It's good practice to get tested if you think you may be at risk for lung cancer or begin to experience symptoms.
A healthcare provider will work with a pulmonologist and oncologist during your diagnostic process to run different tests. Common exams for lung cancer include a physical exam and blood and imaging tests. These tests can help confirm a diagnosis and rule out other conditions.
Lung cancer is an aggressive condition, and getting tested can be scary. It's OK to feel overwhelmed. Remember that an early diagnosis can help you manage your condition and find a treatment plan that is right for you.
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