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Screening Smarter in Lung Cancer

Otis Brawley, MD, discusses informed decision-making and understanding the risk-benefit ratio of CT scans

By Morgan Lord
July 7, 2026 | VOLUME 4, ISSUE 2

As researchers have conducted more comprehensive lung cancer screening studies over the years, the pros and cons of the screening process have become more apparent.

On the positive side, the National Lung Screening Trial showed that annual screening with low-dose CT scans in individuals at high risk reduced lung cancer mortality by about 20% compared with chest X-ray screening.¹

“This finding was surprising and really important,” said Otis Brawley, MD, of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins. “It showed we have a screening test to help some people who have the most common cause of cancer death.”

Otis Brawley, MD
Bloomberg Distinguished Professor of Oncology and Epidemiology, Johns Hopkins University
Associate Director, Community Outreach and Engagement, Sidney Kimmel Comprehensive Cancer Center

Still, research has shed light on a number of downsides associated with low-dose CT scan screening.

In a devoted effort to thwart these concerns, Dr. Brawley has focused on developing cancer screening strategies and ensuring their effectiveness over the past three decades.

“I think we need to be very honest about what the harms are, even when they are minimal,” Dr. Brawley said. “We need to try to work hard to get the public to understand the risk-benefit ratio of every intervention.”

Feeding the problem

While CT scans are frequently lifesaving in general, their potential harms are often overlooked.

According to a 2025 study published in JAMA, CT scan usage is on the rise. In 2007, a total of 68.7 million CT scan examinations were performed in the United States. In 2023, the number was 93 million—a 35% increase “incompletely explained by population growth.”²

In fact, the study estimated that with the current prevalence of CT scan usage and at the current radiation dose, CT scans could eventually be responsible for 5% of cancer diagnoses annually. This would place CT scans on par with other significant risk factors such as alcohol consumption (5.4%) and excess body weight (7.6%).

“I'm confident that some cancer in the United States is caused by medical radiation,” Dr. Brawley said. He estimates that CT scans could be responsible for around 1.5% to 2% of cancer diagnoses annually. And it may be higher in children because they are more sensitive to radiation than adults; their longer life expectancy provides a larger window for potential damage to develop, he added.

“A kid who gets a CT scan at [age] 5 has until the age of 70 or 80 to get cancer from it,” Dr. Brawley said.

2007

68.7 M

CT scans performed in US

→

2023

93 M

CT scans performed in US

Positively maybe

The National Lung Screening Trial showed that CT scans had a high rate of false-positive tests, Dr. Brawley said.

Though it’s important to catch any cancer before it spreads, sometimes internal scars can look like cancer and disrupting them through procedures can more harm than good, he noted.

Consider this example. “The radiologist will say there’s something here that could be cancer, or it could be a scar from a viral infection 60 years ago, or it could be a scar from a fungal infection last year. But it could be cancer, and the only way you’ll know it is if somebody puts a biopsy needle into it,” Dr. Brawley said.

This can potentially lead to a dangerous domino effect of unnecessary medical care. If you biopsy the chest of a person who has smoked for 20 or more years and they have blebs (fragile air sacs) in their lungs, you might hit a bleb and collapse a lung, Dr. Brawley continued.

“If you collapse a lung, they’ve got a 60-year-old heart and may have coronary artery disease. A collapsed lung can cause a heart attack, and they might die from that heart attack before you can get that lung reinflated.”

Dr. Brawley’s cautionary tale should not be confused with deterrence, however.

“People who have a smoking history, have access to high-quality screening, and understand the pros and cons should be screened,” he said, with an emphasis on “high-quality.”

“We need to try to work hard to get the public to understand the risk-benefit ratio of every intervention.”

Know ‘where’ before ‘what’

The quality of the hospital and choosing one with an established program is key.

“You need to realize that the National Lung Screening Trial was done in 33 of the greatest hospitals in the United States, where for every 85 lives saved, 16 lives were lost,” Dr. Brawley said. “That 5.4-to-1 ratio is good for when you get it done at a quality place, but that’s not what the benefit-to-risk ratio would be when it’s done at a small community hospital that doesn’t do a lot of lung screening or lung cancer treatment.”

It’s important to seek out a facility that has an established program and does lots of lung cancer screening diagnosis and treatment, Dr. Brawley emphasized.

If you get screened at a hospital without an established, quality program, you run the risk of encountering equipment that is lacking or out of date, which can lead to longer waits.

Cost can be another repercussion of not choosing a hospital with an established lung cancer program—especially if one scan leads to others—because the diagnostic roller coaster can be very stressful financially for patients without insurance.

“There’s something here that could be cancer, or it could be a scar from a viral infection 60 years ago.”

The more you know

For Dr. Brawley, it all comes back to informed decision-making.

First, clinicians and patients should be aware of the suggested criteria for who should be screened. The US Preventive Services Task Force recommends annual lung cancer screenings for anyone between ages 50 and 80 who has a 20-pack-year history (one pack a day for 20 years, two packs a day for 10 years, etc), anyone who currently smokes, or anyone who has quit within the last 15 years.³

Second, Medicare now mandates education about the potential risks and benefits of CT scans and will pay for a spiral CT scan only after a one-hour conversation between a clinician and the patient. The patient needs to be informed of the potential risks and benefits of the scan, and then they can decide whether they want to get screened.

Overall, Dr. Brawley said he supports screenings for anyone with the appropriate medical history who has access to high-quality lung cancer screening diagnostics and treatment, assuming they understand the bigger picture of harm and benefit.

“If they understand there’s a benefit and there’s a harm and they want to get screened, I think those people ought to be able to get screened,” Dr. Brawley said.

References

National Lung Screening Trial Research Team, Aberle DR, Adams AM, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med. 2011;365(5):395-409. doi:10.1056/NEJMoa1102873
Smith-Bindman R, Chu PW, Azman Firdaus H, et al. Projected lifetime cancer risks from current computed tomography imaging. JAMA Intern Med.2025;185(6):710–719. doi:10.1001/jamainternmed.2025.0505
US Preventive Services Task Force. Lung cancer: screening. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/lung-cancer-screening