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Experts in lung care can agree on one thing: Routine lung cancer screening is saving lives among people who are currently eligible.

However, a recent joint statement from the Society for Thoracic Surgeons, the American Society for Radiation Oncology, and the American College of Radiology (ACR) has sparked debate about the other side of lung cancer screening: its potential harms.

The statement questioned the integrity of certain studies that have attempted to estimate the real-world harms from lung cancer screening — contending that they are flawed and overstate the risks. And its authors suggested that “persistent misinformation about perceived harms continues to limit the uptake of this life-saving test.”

It is true that uptake is far below target: Only about 18% of Americans eligible for lung cancer screening are up to date with it. However, not everyone agrees with the medical groups’ take on the issue.

Do Studies Overestimate Downstream Risks?

According to the statement authors, led by Elliot Servais, MD, of Labey Hospital & Medical Center in Burlington, Massachusetts, there are three main areas of “misinformation” when it comes to lung cancer screening harms.

One is what they consider an exaggerated risk of downstream procedures and associated complications. As an example, the authors point to a 2024 study of real-world data that reported substantially higher rates of follow-up imaging, procedures and complications compared with the landmark National Lung Screening Trial (NLST).

The study included nearly 9300 screened patients at five US healthcare systems. It found that almost one third needed follow-up imaging after a baseline scan, whereas just under 3% had an invasive procedure. Of those who underwent invasive procedures, the rate of major complications was more than double that seen in NLST: 20.6% vs 9.4%.

Servais’s team criticized the study for relying on electronic health records (HER), noting that coding lacks clinical context and may overestimate harms from screening when other issues, such as preexisting conditions, might often be to blame.

But Katharine Rendle, PhD, the lead author on the study, defended her work.

“Despite challenges and limitations inherent in measuring outcomes in real-world practices, I stand by the strengths and rigor of our study,” Rendle, an associate professor at the University of Pennsylvania in Philadelphia, told Medscape Medical News.

She acknowledged the limitations of EHR data but said “we did the best we could with the methods we had.”

The study’s reliance on EHRs simply reflects the difficulty of collecting real-world data on screening harms, according to Gerard Silvestri, MD, a lung cancer specialist at the Medical University of South Carolina’s Hollings Cancer Center in Charleston, South Carolina.

And NLST figures are not necessarily the “right” ones. As Silvestri pointed out, the trial setting is inherently different from the real world.

“If you’re screening out in the community, they’re older, they’re sicker,” compared with the NLST population, said Silvestri, who runs a large lung cancer screening program in South Carolina.

In addition, he said, trial participants were seen at National Cancer Institute-designated cancer centers, where the level of care was “top-flight” and postscreening complications were minimized.

According to Silvestri, all of this suggests that the number of downstream harms to patients screened in the community would exceed those reported in the NLST — in line with Rendle’s findings.

Inflated False-Positive Rates?

The medical groups’ statement also highlights what they call a misrepresentation of the false-positive rate from lung cancer screening. They cite numerous papers, including a 2023 expert consensus statement, for incorrectly reporting that the NLST had a false-positive rate of 96.4%. In fact, that was the trial’s false-discovery rate — or the proportion of positive screens that did not ultimately represent cancer.

The NLST’s actual per-screen false-positive rate was 26.6% at baseline, and it declined to about 22% in subsequent screenings.

Mislabeling the false-discovery rate as the false-positive rate, the statement contended, “creates the impression that nearly every lung cancer screening scan results in unnecessary testing.”

And that’s far from the truth, noted Kim Lori Sandler, MD, a radiologist who directs the lung screening program at Vanderbilt University Medical Center in Nashville, Tennessee.

“It’s very, very unusual that we get a scan and we are so concerned that we immediately want to go to an invasive procedure like a biopsy,” Sandler told Medscape Medical News.

More often, she said, patients might undergo a second scan 3 or 6 months later.

And even when screening yields a false-positive, Sandler said, that doesn’t automatically mean the finding is unimportant: The patient may have an infection, aneurysm, or other condition that needs treatment.

Sandler, who was not involved in the joint statement, said that “on the whole, I believe screening can be done very safely, particularly when you have accredited facilities that are imaging appropriately.”

For his part, Silvestri again doubted that the real world is in line with the NLST, saying that false-positive rates in community screening are likely higher than the trial’s.

But the bigger issue, he said, is in how the statement frames the false-positive rate — as if it is “only” in the 27% range, when that is, in fact, a substantial figure.

Is There a Cancer Risk From CT Screening?

Finally, the statement points to “flawed analysis” of the cancer risk associated with CT scan radiation. The authors specifically take aim at a JAMA Internal Medicine study that garnered widespread media attention last year. It estimated that CT scans performed in the US in 2023 alone will result in 100,000 lifetime cancers.

As previously reported by Medscape Medical News, that study also received numerous criticisms of its methodology, and the joint statement reiterates some of them — including the researchers’ use of a risk tool that’s primarily based on data from Japanese atomic bomb survivors.

Sandler said that, given the paucity of good data on long-term risks from radiation, it wasn’t “wrong” to use that risk assessment tool. “But I think it’s important to be upfront about where it comes from.”

Not all radiation is the same, Sandler noted, and being exposed to an extreme dose at once is “very different” from exposure to low-dose CT scans over time.

In addition, she noted, radiation doses from chest CT are falling as technology improves — such that they are generally lower now than even 15 years ago, when the NLST was published.

For their part, the authors of thestudy were careful to say they were highlighting potential harms from unnecessary CT scans and/or higher-than-necessary radiation doses — and not trying to scare patients away from medically justified scans.

What’s Really Keeping People From Screening?

In a press release announcing the statement, the ACR asserted that flawed research may be causing eligible patients to forgo or even not be offered lung cancer screening.

But according to Silvestri, the groups may be missing the real reason many people aren’t being screened: socioeconomics.

He stressed that he’s a strong advocate for lung cancer screening under current eligibility guidelines, which target certain smokers and former smokers: “It can reduce lung cancer mortality by 20% — that’s a huge number.”

At the same time, Silvestri said, this is a difficult patient population to reach. Compared with lifelong nonsmokers, they tend to have less education and are more likely to be underinsured. And many face practical barriers, such as getting time off from work to go for screening and any necessary follow-up.

The statement authors, according to Silvestri, seem to be suggesting that if it weren’t for what they consider flawed research on harms, “we’d all of a sudden be screening the whole population.”

“I think that is likely not the case,” he said.

There is at least one point of wide agreement: Lung cancer screening can save lives, and efforts to make it as safe and accessible as possible for eligible people should be encouraged.

Rendle said that in studying the potential downstream harms, her team’s aim was never to discourage screening uptake. In fact, she added, tracking the benefits and risks of lung cancer screening in the real world is necessary for it to work optimally.

Such research, Rendle said, will help “ensure that we are maximizing benefits of screening, and identify any opportunities for improving the diagnostic process across community practice.”

Ernie Mundell is a freelance medical journalist based in Los Angeles. He has more than 30 years of experience, including editorial positions at Reuters Health and HealthDay.