Lung Cancer Screening with Low-Dose CT: The Life-Saving Test Too Many People Skip

Lung cancer screening with annual LDCT scans can significantly reduce lung cancer deaths through early detection for those at high risk. Early detection, combined with smoking cessation and reducing exposure to other risk factors, represents our best strategy in the fight against lung cancer.

Statistics and Impact of Lung Cancer

Lung cancer is the second most common type of cancer in the world and the leading cause of cancer deaths. More than 80% of these cases are attributed to smoking cigarettes. This means that most cases of lung cancer are preventable¹. 

Lung cancer screening guidelines were developed to decrease mortality and improve survival rates with early detection. Here, we’ll discuss what you need to know about current lung cancer screening guidelines and the benefits of early detection.

According to the CDC, lung cancer was responsible for over 20% of all cancer deaths in 2020, making it more deadly than colon, prostate, and breast cancer combined.

The American Cancer Society estimates that there will be over 238,000 new cases of lung cancer in the US in 2023². Unfortunately, many of these cases aren't discovered until the advanced stages because lung cancers often grow silently before symptoms actually appear. Only 16% of lung cancers are diagnosed at an early stage, so the average five-year survival rate for all lung-cancer types combined is only around 18.6 percent. Sadly, more than half of all people with lung cancer die within 1 year of their diagnosis³.

Importance of Early Detection

When detected early while still localized to one lung, the survival rate increases dramatically to nearly 60% compared to only 6% for metastatic lung cancer. Localized lung cancer, where the cancer is discovered while it's confined to one lung, has a survival rate of nearly 60%. Metastatic lung cancer, which is cancer that has expanded to other parts of the body, has a survival rate of only 6%. That's a 10 times increase in survival rates for early-stage lung cancer compared to late-stage, according to data from the National Cancer Institute⁴.

This guide consolidates the latest information on lung cancer screening to help you understand your risk factors, screening options, and the importance of early detection.

Understanding Lung Cancer Risk

Primary Risk Factors

• Smoking: It's the number one cause of lung cancer. Even second-hand smoke can increase your risk. Quitting smoking is your best tool for lowering your risk, but even after quitting your risk for developing lung cancer doesn't go away completely.
  
• Age: Risk increases with age, with most diagnoses occurring in people over 65.
  
• Former smokers: Risk remains elevated even after quitting, though it decreases over time.
  

Risk is measured by "pack years" (number of packs smoked per day multiplied by years of smoking). For example, smoking one pack per day for 20 years equals 20 pack-years, or smoking two packs per day for 10 years.

Additional Risk Factors

• Radon exposure: The second most common cause for lung cancer. Radon is an odorless gas that naturally occurs in soil. Most people are exposed through radon in their homes or other buildings where they spend long periods.
  
• Air pollution: Fine particle pollution consist of particles smaller than the diameter of a single hair. There's growing evidence that exposure of a long period of time can be linked to lung cancer. Even in people that have never smoked.
  
• Hazardous chemicals: Exposures to asbestos, arsenic, chromium and other dangerous chemicals can increase your risk for certain types of lung cancers.
  
• Family history: Having close relatives who had lung cancer may indicate increased risk.
  

If you combine some of these risk factors with smoking that can severely increase your risk for developing lung cancer.

Assessing Your Personal Risk

If you need help calculating your overall cancer risk and specifically lung cancer risk, you can do the Ezra’s Cancer Risk Calculator – it only takes a few minutes. Our team at Ezra can help you understand your risk for lung and other cancers with this 5-minute risk calculator.

Lung Cancer Screening Guidelines and Recommendations

Current USPSTF Eligibility Criteria

According to the U.S. Preventive Services Task Force (USPSTF), American Cancer Society (ACS), American Academy of Family Physicians (AAFP), and the Centers for Disease Control and Prevention (CDC), current lung cancer screening guidelines are as follows⁵:

• Annual screening with low-dose CT for adults 50-80 years old with a 20 pack-year history of smoking and are either current smokers or have quit smoking within the past 15 years.

When to Start and Stop Screening

Annual lung cancer screening can stop once:

• Someone has not smoked for at least 15 years
• Is older than 80 years old
• Has another medical condition that would limit their ability to undergo surgery for a lung cancer diagnosis

A key point here is that former smokers should still be getting an annual low-dose CT screening until they have stopped smoking for more than 15 years.

Medicare Coverage Information

Medicare covers lung cancer screening based on the USPSTF criteria along with one additional point that you're asymptomatic⁶.

Low-Dose CT Scan & Other Screening Methods

Low-Dose CT Scan Explained

An LDCT, or low-dose Computed Tomography (CT) scan, is a recommended screening procedure for adults at high risk of lung cancer.

Low-dose CT scans use a similar technology to regular CT scans but emit much less ionizing radiation. The amount of exposure to radiation during an LDCT scan is generally considered safe and is FDA regulated and approved⁷.

The most common screening test for lung cancer is a low-dose CT (LDCT) scan. LDCT scans use low levels of radiation to create detailed images of the lungs. These images can help identify small nodules or growths that may be cancerous. This is considered the gold standard when it comes to lung cancer screening.

Why LDCT vs. Standard CT or MRI?

LDCT vs. Standard CT Scan

Both regular CT scans and low-dose CT scans produce high-quality images that allow for early detection of lung cancer⁸.

Radiation exposure is the most significant difference.

• A standard chest CT scan exposes you to about 7mSv of ionizing radiation⁹.
• A low-dose CT lung cancer screening exposes you to about 1.5mSv — 3mSv of ionizing radiation, according to the American College of Radiology.
• For perspective, the average environmental radiation exposure in the United States is about 3 mSv per year.

‍

‍Why Not Use MRI?

The lungs present unique challenges.

The first has to do with signal intensity.

When assessing MRI images, radiologists refer to the shade of gray representing tissues or fluids with the word "intensity." Lungs exhibit a low signal intensity, showing up as black on MRI scans. Because lungs are so dark, it's difficult to discern lesions and nodules.

CT scans produce high-quality images that allow radiologists to visualize lesions and lung nodules and better understand your lung health.

The second relates to motion.

MRI scans are affected by the motion of the lungs¹⁰. Breathing can blur MRI images, making them even more challenging to read and interpret.

CT scans, on the other hand, are much faster. This is particularly important for patients who have trouble holding their breath.

To ensure high-quality results, Ezra forgoes chest MRI and recommends LDCT instead.

Radiation Exposure Context and Safety

Unlike MRI scans, CT scans work through a combination of X-rays and computer processing to produce pictures of your body's tissues and organs.

X-rays are a form of ionizing radiation, which is potentially harmful.

Ionizing radiation is a type of energy that removes electrons from the atoms and molecules making up living tissues.

While Ezra's LDCT is safe, it does expose you to this radiation, which is associated with a slight increase in cancer risk. However, the knowledge gathered from the screening dramatically outweighs the risks of not having it, especially if lung cancer is discovered.

The exact amount of radiation you'll receive depends on the specific radiation used and the amount of radiation your body absorbs. This means each person's radiation exposure depends on the particular protocol used and an individual's body composition and size.

As humans, we're all exposed to radiation daily. We call this background radiation. Background radiation comes from environmental factors like cosmic rays, radon, rocks, and soil. Your exposure to additional radiation depends on where you live, what you eat, and what you do for work.

We measure our exposure to radiation in millisieverts (mSv).

Here are some expected exposure levels:

• The average American is exposed to 3mSv of background radiation per year, according to the National Cancer Institute¹¹.
• Radiation exposure can increase 1.5mSv per year for those living at high altitudes like Colorado and New Mexico¹¹.
• Those in the armed forces are typically exposed to an additional 1mSv per year¹².
• On average, flight attendants and pilots are exposed to an additional 3mSv per year¹³.
• Astronauts can be exposed to up to 150mSv of radiation, while on the International Space Station¹⁴.
• A standard chest CT scan exposes you to a typical effective dose of 7mSv¹⁵.
• A LDCT for lung cancer screening exposes you to approximately 1.5mSv — 3mSv of ionizing radiation, according to the American College of Radiology¹⁶.

Calculate your average background radiation if you live in the US by going to the Environmental Protection Agency's website.

So, while an LDCT screening does expose you to radiation, it's lower than a standard chest CT scan and well within acceptable safety limits.

If you’d like to estimate how your cancer risk may increase, visit xrayrisk.com, select Chest CT (Low Dose Screening), and enter your age and gender.

Benefits of Lung Cancer Screening

Screening for lung cancer, especially for people at high risk can be a life-saver.

Many of the risk factors for a poor prognosis involve your general health, the type of cancer, and amount of spread when the cancer is found. Lung cancer is especially deadly because people can go for a long time without symptoms, even as the lung cancer spreads in through their body. Often when symptoms like persistent cough, weight loss, chest pain, shortness of breathing, or coughing up blood occur, it's too late for curative treatment.

Researchers have found that screening with LDCT dramatically improves the survival rate for lung cancer patients because doctors can diagnose more early-stage lung cancer leading to more curative treatment options¹⁷. This can reduce the risk of dying from lung cancer by up to 20% in people with a high-risk.

Along with decreasing lung cancer mortality with early detection, this annual screening program is important because it can provide a baseline picture of someone's lungs. This can be very beneficial if a lung nodule is seen but does not grow over time, increasing the probability of it being benign (non-cancerous). It can also monitor the stability of other lung findings, such as emphysema.

Lung Cancer Screening Process

What to Expect During LDCT

LDCT scans are quick and painless. The scan itself only takes about 5 minutes to complete. You'll lie on a table that slides into a donut-shaped machine. The technologist will ask you to hold your breath for a few seconds while the images are taken.

The 10 Pillars of Lung Cancer Screening

The 10 pillars of lung cancer screening refer to a step-wise approach to ensure the millions of Americans who qualify for lung cancer screening receive the proper care and are appropriately reimbursed for that care²⁰. These 10 pillars include:

1. Eligibility: This refers to the eligibility criteria, including age and smoking.
2. Education: This includes shared decision-making between the person and the healthcare provider to weigh the benefits and risks of lung cancer screening.
3. Examination ordering: This helps determine which healthcare provider or group may be responsible for ensuring a qualified person receives their scan annually and without delay.
4. Image acquisition: Under current recommendations, the best lung cancer screening imaging test is the low-dose CT scan.
5. Image review: Images are reviewed by a radiologist who will look for any suspicious lung nodules or masses.
6. Communication: This refers to communication between radiologists and the person's healthcare provider to ensure there's no delay in follow-up.
7. Referral network: This is key when an abnormal finding is discovered to ensure the person promptly sees a proper specialist, such as a pulmonologist or thoracic surgeon.
8. Quality improvement: This identifies areas of care that could be more effective or more efficient.
9. Reimbursement: This refers to the payment for lung cancer screening. For example, lung cancer screening is covered by Medicare based on the USPSTF criteria along with one additional point that you're asymptomatic.
10. Research frontiers: Ongoing research regarding lung cancer screening guidelines is crucial as it could lead to changing criteria so even more people can qualify.

Available Screening Programs at Ezra

Ezra offers a screening for lung cancer with a LDCT in addition to other screening tests. 

If you are considering an Ezra LDCT, full-body MRI, or gifting an Ezra LDCT or full-body MRI to a loved one, schedule a call with our team to learn more.

Limitations and Considerations

Potential Risks of Screening

The risks of LDCT screening include:

• Radiation exposure: While the amount of radiation used in LDCT scans is low, repeated scans over time can increase the risk of radiation exposure and potential harm. Though the radiation exposure risk is small per scan, repeated LDCT screening tests over time may potentially lead to a higher risk of cancer in some people.
  
• False negatives: This is when a cancer is not picked up by the scan, and usually requires repeated follow-up scans to increase detection accuracy. Cancer may sometimes be missed on a scan.
  
• Overdiagnosis: This is when some cases of cancer are found that may have never caused a problem for the person. For example, maybe a lung mass was found on LDCT that never would have grown or spread. This can then lead to follow-up treatment that otherwise may not have been needed. It's unclear how often this happens.
  

False Positives and False Negatives

• False positives: LDCT scans can detect nodules or growths that may not be cancerous. A large-scale clinical trial found the false-positive rate for LDCT to be approximately 27%¹⁸. That's when LDCT scans can detect nodules or growths that may not be cancerous, leading to unnecessary additional testing or procedures.

One of the risks of lung cancer screening doctors commonly discuss with their patients is the risk for a false positive.

Management of Screen-Detected Nodules

Here's where some guidance from medical experts fits in. The Fleischner Society Guidelines and LUNG-RADs are two sets of guidelines used to evaluate and manage lung nodules found on imaging tests¹⁹. These guidelines are used to help doctors determine whether a nodule is likely to be cancerous or benign and how to proceed with further testing and treatment.

When LDCT screening identifies lung nodules, guidelines from the Fleischner Society and Lung-RADS (Lung CT Screening Reporting and Data System) help determine whether a nodule is likely cancerous and how to proceed with further testing and treatment.

If a suspicious lung nodule is found, follow-up may include:

• Repeat LDCT scans to monitor growth
• Additional imaging
• Biopsy procedures, which may be performed via:
  
  • Needle biopsy through the skin
  • Bronchoscopy through the windpipe
  • Thoracoscopic biopsy through the chest wall
  • Open biopsy during surgery

Beyond Screening: Comprehensive Lung Health

Lung Function Tests and Their Purpose

Lung function tests (also called pulmonary function tests) are an important part of evaluating lung health and diagnosing lung conditions. These non-invasive exams measure how well your lungs work.

Types of Lung Function Tests

1. Spirometry: The most basic lung function test that measures:
   
   • How much air your lungs can hold
   • How much force you can use to expel air
   • This test can screen for diseases like asthma and COPD that affect lung volume
2. Lung Volume Testing: More precise than spirometry, this test measures:
   
   • The total volume of air in your lungs
   • How much air remains inside your lungs after a normal breath
3. Diffusing Capacity Tests: These measure how easily oxygen enters your bloodstream from your lungs
4. Exercise Testing: This examines potential causes of shortness of breath during physical activity
   
   

What to Expect During Lung Function Tests

Lung function tests are:

• Painless and non-invasive
• May require maximal effort to breathe in and expel air
• Often performed before and after administering a bronchodilator medication to check for improvement

These tests are valuable for:

• Diagnosing respiratory conditions
• Monitoring existing lung disease
• Evaluating how well treatments are working
• Assessing lung function before surgery
• Complementing imaging studies like LDCT in evaluating overall lung health

When to See a Doctor (Symptoms)

Consult a healthcare provider immediately if you experience:

• Persistent cough
• Coughing up blood (even small amounts)
• Chest pain
• Shortness of breath
• Hoarseness of voice
• Unintentional weight loss
• Headaches or bone pain

Lung Cancer Prevention Strategies

Although there's no way to completely safeguard yourself from cancer, early detection and taking steps to stay healthy are key to reduce your risk. Here are some actionable steps for lung cancer prevention:

• Quit smoking: This is the single most effective way to reduce the risk of lung cancer. If you smoke, quitting is the best thing you can do for your health. There are many resources available to help you quit smoking, including nicotine replacement therapy, counseling, and support services.
  
• Avoid exposure to secondhand smoke: If you don't smoke, but you're regularly exposed to secondhand smoke, you're still at risk for lung cancer²¹. Avoid spending time in places where people smoke, and encourage your loved ones to quit smoking as well.
  
• Test your home for radon: You can buy a radon testing kit at a hardware store, or you can hire a professional to test your home for you.
  
• Reduce exposure to air pollution: Air pollution can increase the risk of lung cancer, especially for people who live in urban areas. You can reduce your exposure by avoiding areas with high levels of pollution, using air filters in your home, and using public transportation instead of driving.
  
• Plan for early detection: Routine health screening tests, like the Ezra Lung CT scan, may help alert you or your loved one to the earliest signs of lung cancer. Here's a video for more information.
  
• Talk to loved ones about their risks: If you are worried about some one you love, check out this information for tips about encouraging your loved one to get screened.
  
• Keep track of your overall health: Ezra's full-body MRI screening provides a look into your overall health and helps detect signs of potential early cancer or early disease. It can help assess the current status of your health, monitor your body across time, and flag any abnormalities early.
  
• Ask questions and get informed: We want to make sure you have all the information and resources you need when it comes to lung cancer screening.

The American Cancer Society has written an excellent guide on smoking cessation, and the SAMHSA offers a National Helpline for those in need.

For more information about lung cancer screening programs, risk assessment tools, or to schedule a screening, consult with your healthcare provider.

References

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2. SEER Cancer Stat Facts: Lung and Bronchus Cancer. National Cancer Institute. Accessed April 3, 2025. https://seer.cancer.gov/statfacts/html/lungb.html
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4. Lung Cancer Survival Rates. WebMD. Accessed April 3, 2025. https://www.webmd.com/lung-cancer/guide/lung-cancer-survival-rates
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6. Lung Cancer Screenings. Medicare.gov. Accessed April 3, 2025. https://www.medicare.gov/coverage/lung-cancer-screenings
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