Lung cancer is the country's most lethal cancer, with over 127,000 people dying of the disease every year. The American Cancer Society on Wednesday updated its lung cancer screening recommendations, expanding the pool of current and former smokers who should be screened for it every year, starting at age 50.

The ACS's Chief Scientific Officer Dr. William Dahut says catching lung cancer early matters more than ever.

"There are so many new treatments out now for lung cancer, so many new targeted therapies, that the chances for survival is so much better if one is diagnosed earlier on," Dahut says.

The new recommendations expand the age range for testing, to between 50 and 80. Previously, the age range had been 55 to 74. The group is also getting rid of a barrier to screening for former smokers. The previous guidelines said if you quit smoking more than 15 years ago, you didn't necessarily need to be screened. Now even someone who quit 40 years ago might be eligible to be screened.

Screenings are reserved for current smokers and people who smoked heavily in the past in that age range. This is defined as at least a pack a day for 20 years. However, the American Cancer Society has a "pack year" measurement to quantify very heavy smoking. For example, someone who smoked two packs a day for 10 years is equivalent to 20 "pack years" and should be screened yearly starting at age 50 under the new guidelines.

ACS estimates an additional 5 million Americans should be scanned under the new guidelines. The screening test is a low-dose computed tomography scan (also called a low-dose CT scan, or LDCT).

In 2023, ACS researchers estimate 238,340 new cases of lung cancer (117,550 in men and 120,790 in women) will be diagnosed. By the time people are symptomatic, treatment options can be limited, so screening offers a better chance for new treatments to succeed.

Anyone at any age can get lung cancer. However, lung cancer mainly occurs in older people, as most people diagnosed with the disease are aged 65 or older, ACS says.

The guidelines for screening were last updated in 2013.

The expanded screening recommendations "could make a real difference in saving lives," says Dr. Robert Smith, who leads early cancer detection science at ACS and is the lead author of the screening guideline report.