How Does Lung Cancer Screening Work?

Lung cancer is the most common cancer worldwide and the leading cause of cancer-related deaths in the United States. Smoking causes nearly 90% of all lung cancer cases, but people who have never smoked can also be affected. Exposure to toxic substances (e.g., asbestos, radon), environmental pollution, and genetics can also play a role in developing the disease.

This article will provide an overview of lung cancer screening and discuss who needs lung cancer screening and the various screening methods.

Healthcare professional holding digital tablet with X-ray scan images of the lungs.

Prapass Pulsub / Getty Images

What Is Lung Cancer Screening?

Lung cancer screening uses imaging and diagnostic tests to identify lung cancer before symptoms develop. Screening aims to detect lung cancer early, when it is most treatable.

Early detection of lung cancer increases survival rates to 59%, compared to a 22.6% survival rate in later stages of the disease.

A low-dose computed tomography (CT) scan (LDCT) is the recommended test for lung cancer screening. LDCT uses a computer with an X-ray machine to take multiple images of the lungs and surrounding tissues.

The images produced by an LDCT are so detailed they can reveal minor lung abnormalities that a traditional X-ray machine would not be able to detect.

Who Is Lung Cancer Screening For?

Annual lung cancer screening is recommended for people who:

  • Are between 50 and 80 years old 
  • Currently smoke or have quit smoking in the past 15 years
  • Have a 20 or more pack-year (a calculation of how many cigarettes you have smoked in your lifetime) smoking history

Your healthcare provider may recommend yearly lung cancer screening if you have other risk factors such as a family or personal history of lung cancer, chronic obstructive pulmonary disease (COPD), or exposure to environmental toxins.

What to Expect

Your healthcare provider will consider your age, smoking history, previous exposure to harmful substances, and other factors when determining whether you meet the criteria for lung cancer screening. 

If you qualify, your healthcare provider will discuss the risks and benefits and share details about what to expect. 

An LDCT scan is a minimally invasive, painless procedure. No special preparation is required, but you may need to reschedule if you have a respiratory infection on the day of your scan.

Before the scan begins, you will lie very still on your back on the CT machine table with your arms raised above your head. The table slowly moves through the CT machine's center while an X-ray machine takes images of the lungs and chest. The scan itself lasts less than one minute.

The Benefit of Lung Cancer Screening

The benefit of lung cancer screening is detecting cancer early enough screening that it is curable and prevents death. Screening detects 80% of lung cancer in its early stages.

Other Imaging Procedures for Lung Cancer Diagnosis

Imaging tests cannot confirm a lung cancer diagnosis, but they help give your healthcare provider a clear picture of your lungs to detect abnormalities, such as nodules (spots) and masses. Below are additional imaging procedures used for lung cancer diagnosis.

Chest X-Ray

An X-ray creates pictures of the inside of the body. A chest X-ray will show your healthcare provider pictures of the organs and bones in your chest, including your lungs.

Chest X-rays often miss early-stage lung cancers but can detect larger masses. They are not a good tool for diagnosing lung cancer but are helpful when the diagnosis is confirmed to check if the tumor has grown larger.

Computed Tomography (CT) Scan


CT scans use an X-ray machine connected to a computer to take pictures inside the body. A CT scanner rotates around the body during the scan to take multiple images from different angles.

A CT scan can provide detailed information about any lung nodules' size, shape, and position. It can also detect enlarged lymph nodes or masses in other organs to determine if lung cancer has spread to other areas of the body.

Magnetic Resonance Imaging (MRI) Scan

MRI uses radio waves and a strong magnetic field to produce two- and three-dimensional images of the inside of the body. Before the scan, a contrast dye is injected into the veins to help make clearer images. MRI scans help to determine if lung cancer has spread to the brain or spinal cord. 

Positron-Emission Tomography (PET) Scan

A PET scan uses short-acting radioactive sugar (glucose) to show where cancer cells are in the body. Cancer cells absorb more sugar than healthy cells, so a PET scan can help detect the sugar concentrations and reveal where cancer cells are throughout the body.

Bone Scan

A bone scan detects possible bone damage or disease by injecting a small amount of radioactive substance (tracer) into a vein. Within a couple of hours, the tracer settles into bones that may be injured or affected by the disease.

People diagnosed with lung cancer get bone scans to determine if cancer has spread (metastasized) to the bones. Up to 36% of lung cancer patients experience bone metastases.

Additional Testing

Though an LDCT test is the "gold standard" screening test to diagnose lung cancer, your healthcare provider may recommend additional tests to check for cancer cells and provide a diagnosis.

Sputum Cytology

Sputum cytology is a test that examines a sample of lung secretions or phlegm (mucus) under a microscope to look for cancer cells. This test is not practical for diagnosing lung cancer; one study found that sputum cytology missed the diagnosis 42% of the time.

Thoracentesis

Thoracentesis is a procedure that removes some of the fluid located between the chest wall and lungs to check for cancer cells. In healthy people, there is a thin layer of fluid in this space, but some conditions like lung cancer can cause excessive fluid buildup, known as pleural effusion.

Needle Biopsy

A needle biopsy is a procedure that uses a hollow needle to remove a tissue sample from the lung or suspicious nodule/mass. The sample is examined under a microscope to check for cancer cells. A biopsy is the best way to confirm a cancer diagnosis. It can also help healthcare providers identify what type of lung cancer it is.

Bronchoscopy

A bronchoscopy is a procedure that involves using a thin, flexible tube (bronchoscope) with a light and camera lens at the end to look into the airways of the lungs.

This test helps healthcare providers get a closer look at any suspicious areas in the airways. A tissue sample may be taken during a bronchoscopy to biopsy and diagnose lung cancer. 

Results

Your healthcare provider and a specialist like a radiologist will review your screening test results. If nodules or cancer cells are not detected, your healthcare provider will tell you when to schedule your next screening test. Most people who meet the criteria for low-dose CT scans should get them yearly.

If you are not diagnosed with lung cancer but are still experiencing symptoms, your provider may order more tests to ensure an accurate diagnosis. 

If you are diagnosed with lung cancer, your healthcare provider will discuss the next steps and treatment options.

Summary 

Lung cancer screening uses imaging scans and other tests to detect and diagnose lung cancer in its earliest stages when it is most treatable. People at high risk for lung cancer should get an annual LDCT screening test. Talk to your healthcare provider if you have early signs of lung cancer. They may recommend lung cancer screening to provide a diagnosis. 

A Word From Verywell 

Lung cancer screening can detect the disease in its early stages to increase your chances of being cured. Feeling worried or hesitant about screening is normal if you have certain risk factors, such as a smoking history. But don’t let these fears hold you back; lung cancer screening may save your life.

Frequently Asked Questions

  • What health screening is used for lung cancer?

    Low-dose computed tomography, also known as low-dose CT scan (LDCT), is the recommended health screening for lung cancer. Your healthcare provider may order additional screening tests (e.g., biopsy, PET scan) to confirm a diagnosis if something is detected on the LDCT. 

  • What are the early signs of lung cancer?

    Persistent cough, chest pain, shortness of breath, repeated respiratory infections and unintentional weight loss are early signs and symptoms of lung cancer.

  • Who should be screened yearly for lung cancer?

    Annual lung screening is recommended for people who currently smoke, have smoked in the past 15 years, are between 50 and 80 years old and in fairly good health, and/or have a 20 pack-year or more smoking history.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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