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• Posted January 3, 2024

Lung Cancer CT Screening Can Save Lives, But Study Finds Downsides

WEDNESDAY, Jan. 3, 2024 -- Numerous studies have confirmed that annual lung cancer screening using CT scans does save lives.

However, new data has emerged showing that scans often pick up abnormalities that lead to follow-up invasive tests -- and more complications.

While no one is saying that all smokers and former smokers should skip lung CT scans, "real-world" complication rates after screening could be higher than physicians once assumed, the researchers said.

Doctors may need to "prioritize" screening for those patients who are "most likely to receive a net benefit from screening in relation to potential complications and other harms," explained a team led by Katharine Rendle. She's assistant professor at the University of Pennsylvania's Perelman School of Medicine in Philadelphia.

The findings were published Jan. 2 in the Annals of Internal Medicine.

Lung cancer remains the number one cancer killer, responsible for more than 127,000 deaths in 2023, according to the American Cancer Society.

Early detection can save lives, however. In 2021, the U.S. Preventive Services Task Force (an independent panel of experts) recommended annual lung cancer screening for all adult ages 50 to 80 who have a smoking history of 20 pack-years, meaning they smoked at least 20 cigarettes a day for 20 years or more.

One recent study found that 81% of people whose tumors had been spotted on an annual CT screenings were still alive 20 years later.

However, as in all screening tests, false-positive results (where something that looks like lung cancer turns out to be benign) can happen, leading to unnecessary follow-up tests.

In the large trial that triggered the new screening guidelines, these downstream tests and associated complications were relatively low.

Rendle's team wanted to see if that was still true, as screening became more widespread and moved to a "real-world" setting.

The new study tracked outcomes for nearly 9,300 U.S. patients screened for lung cancer at five major health care systems between 2014 and 2018.

They found that just under 16% of the patients had some type of "abnormality" show up on their CT scans. Of those 1,492 patients, a total of 140 were diagnosed with lung cancer over the following year.

About a third (31.9%) of patients who underwent CT screening received some kind of follow-up scan, while a much smaller number (2.8%) had to undergo a lung biopsy or other invasive test.

Among the latter group, nearly a third (30.6%) had some form of complication because of the procedure -- anything from transient respiratory issues to cardiac arrest or a collapsed lung.

Rendle's team note that this complication rate is much higher than the 17.7% rate seen in the National Lung Screening Trial (NLST), which spurred current lung cancer screening recommendations.

Why the difference?

Rendle's team believe that "real-world" patients are often sicker than those who were selected for the NLST -- they were "older, were more likely to be currently smoking and had a higher rate of co-morbid conditions [other illnesses]."

All of that puts a person at higher risk for a complication following any invasive test, Rendle's team noted.

So, overall "we observed higher rates of both invasive procedures and complications in patients screened for lung cancer" compared to what was observed in the NLST, the researchers said.

This is "a difference that could shift the balance of screening harms and benefits in community practice," Rendle's group wrote.

Smokers and ex-smokers may want to have more detailed discussions with their doctors, weighing the pros and cons of annual CT screening for their particular case, they said.

More information

Find out more about the American Cancer Society's lung cancer screening guidelines.

SOURCE: Annals of Internal Medicine, Jan. 2, 2024