Millions More Smokers Should Be Screened for Lung Cancer—Even if They Quit Long Ago

The American Cancer Society released new guidance on who should get yearly scans for lung cancer, the leading cause of cancer death around the world

Doctor looking at x-ray scan of lungs with patient
Patients who are at high risk of lung cancer can get screened with low-dose computed tomography (CT) scans. Prapass Pulsub / Getty Images

Current and former heavy smokers—even those who stopped smoking years ago—should get annual scans for lung cancer as they age, according to new guidelines released last week by the American Cancer Society (ACS). Under the updated criteria, an additional five million people in the United States are now advised to get screened for the disease.

The group recommends that anyone between 50 and 80 years old who currently smokes or used to smoke should undergo a low-dose computed tomography (CT) scan every year—even if they have no symptoms of lung cancer.

More specifically, the guidance applies to anyone in that age range with a 20 pack-year or greater history of smoking, a calculation that accounts for how many cigarettes they smoked during their lifetime. For example, someone with a 20 pack-year history could have smoked one pack per day for 20 years, or two packs per day for ten years.

With the change, the organization hopes doctors will be able to catch cases of lung cancer sooner, when they have a better chance of treating the disease and preventing it from spreading. In the long run, the guidance is meant to reduce the number of people who die from lung cancer.

In the U.S., lung cancer kills more people than prostate, colon and breast cancers combined. More than 136,000 people died from lung cancer in 2020, according to the most recent data available from the Centers for Disease Control and Prevention (CDC). Lung cancer is the leading cause of cancer death around the world.

Previously, the ACS’s screening guidelines were aimed at people between 55 and 74 years old with a 30 pack-year history. They also only applied to those who had quit smoking within the last 15 years. Now, the group says screening should not depend on how long ago a person stopped smoking.

This change reflects the latest in lung cancer research. Studies suggest the risk of developing lung cancer does not disappear with time after quitting. Instead, risk increases with age, even for people who gave up smoking 15 or more years in the past.

“Lung cancer is a disease of the elderly, and so, basically, your risk starts becoming greatest once you’re in your 60s,” says William Dahut, the ACS’s chief scientific officer, to CNN’s Jacqueline Howard.

To illustrate this point, the ACS gave the example of a business executive in her 50s who smoked two packs a day in high school, college and graduate school but quit at age 30.

“Even though the time she smoked feels in the distant past, she still has a smoking history of 20 pack-years, and her risk of lung cancer will never be as low as a person her age who never smoked,” says Arif Kamal, the ACS’s chief patient officer, in a statement.

Right now, very few Americans get screened for lung cancer—an estimated 5.8 percent of eligible patients nationally. But lung cancer screening can help reduce the risk of death by up to 20 percent.

“Screening works by finding dangerous cancers before they do dangerous things,” says Daniel Boffa, a thoracic surgeon at Yale School of Medicine and Smilow Cancer Hospital, to Health’s Sherri Gordon.

It’s not clear why more people aren’t being scanned for lung cancer, but a lack of awareness may be partially to blame, according to informal surveys.

“We asked people if they had heard about [lung cancer screenings]. Nobody had,” says Chi-Fu Jeffrey Yang, a thoracic surgeon at Massachusetts General Hospital, to NBC News’ Linda Carroll. “But everybody had heard about mammograms for breast cancer, colonoscopies for colorectal cancer and Pap smears for cervical cancer.”

Even some primary care physicians were confused about who needs lung cancer screenings, per NBC News. But the ACS hopes its new guidelines will help clear up these and other issues and, ultimately, “make a real difference in saving lives,” as the report’s lead author, Robert Smith, ACS senior vice president for early cancer detection science, says in a statement.

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