Millions more people need lung cancer screening, ACS says

People with a history of heavy cigarette smoking should be checked regularly for lung cancer even if it's been many years since they quit, the American Cancer Society (ACS) now recommends.

This new recommendation, released Wednesday (Nov. 1) in CA: A Cancer Journal for Clinicians, is a departure from the ACS' previous advice, which said former smokers no longer needed annual screening once they went 15 years without smoking.

"Lung cancer is a disease of the elderly, and so, basically, your risk starts becoming greatest once you're in your 60s, which was probably during this time period when people were stopping to be screened," Dr. William Dahut, chief scientific officer for the ACS, told CNN.

"People developed a false sense of security," which may have contributed to the "abysmally low" rates of screening, Dahut added in an interview with NBC.

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Rates of annual lung cancer screening vary among states, but the national average suggests that only about 10% of eligible people get checked, Robert Smith, senior vice president for early cancer detection science at the ACS and lead author of the guideline, told The Washington Post. Screening involves low-dose computed tomography (low-dose CT), a scan that combines a series of X-rays into a detailed image of the inside of the body.

The small percentage of people who do get screened often fail to get their next scan the following year, Smith said. "I don't think they fully appreciate it is not one-and-done."

In addition to eliminating the years-since-quitting clause, the ACS broadened its guidelines in several other important ways. It used to recommend annual screening to current and former smokers ages 55 to 74 who had at least a 30 "pack-year" smoking history and had quit less than 15 years ago. (Thirty pack-years is the equivalent of smoking one pack of cigarettes per day for 30 years, or two packs a day for 15 years, and so on.)

Now, the ACS recommends that current and former smokers ages 50 to 80 with a 20 pack-year smoking history be screened annually, regardless of whether or when they quit. These changes mean that about 19.3 million people in the U.S. should now be eligible for screening, compared with 14.3 million under the previous guidelines, NBC reported.

The ACS' new guidelines mostly align with recommendations from the U.S. Preventive Services Task Force (USPSTF), a panel of volunteer experts in primary care and prevention. The USPSTF recommends yearly screening to adults 50 to 80 years old with a 20 pack-year smoking history, but it still says people can stop getting screened if it's been more than 15 years since they quit.

"The new guidelines from the American Cancer Society, I think, are reflective of newer modeling evidence," Dr. Matthew Triplette, a pulmonologist and cancer prevention researcher at the Fred Hutchinson Cancer Center in Seattle who wasn't involved with either set of guidelines, told CNN. 

The new evidence suggests that the risk of lung cancer continues to rise as people age, even among those who have quit smoking for 15 or more years.

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