When the American Cancer Society recently unveiled changes to its lung cancer screening guidance, the aim was to remove barriers to screening and catch more cancers in high-risk people earlier.
Although the lung cancer death rate has declined significantly over the past few decades, lung cancer remains the leading cause of cancer deaths worldwide.
Detecting lung cancer early is key to improving survival. Still, lung cancer screening rates are poor. In 2021, the American Lung Association estimated that 14 million US adults qualified for lung cancer screening, but only 5.8% received it.
Smokers or former smokers without symptoms may forgo regular screening and only receive their screening scan after symptoms emerge, explained Janani S. Reisenauer, MD, Division Chair of Thoracic Surgery at Mayo Clinic, Rochester, Minnesota. But by the time symptoms develop, the cancer is typically more advanced, and treatment options become more limited.
The goal of the new American Cancer Society guidelines, published in early November 2023 in CA: A Cancer Journal for Physicians, is to identify lung cancers at earlier stages when they are easier to treat.
Almost 5 million more high-risk people will now qualify for regular lung cancer screening, the guideline authors estimated.
But will expanding screening help reduce deaths from lung cancer? And perhaps just as important, will the guidelines move the needle on the “disappointingly low” lung cancer screening rates up to this point?
“I definitely think it’s a step in the right direction,” said Lecia V. Sequist, MD, MPH, clinical researcher and lung cancer medical oncologist, Massachusetts General Hospital Cancer Center, Boston, Massachusetts.
The new guidelines lowered the age for annual lung cancer screening among asymptomatic former or current smokers from 55-74 years to 50-80 years. The update also now considers a high-risk person anyone with a 20-pack-year history, down from a 30-pack-year history, and removes the requirement that former smokers must have quit within 15 years to be eligible for screening.
As people age, their risk for lung cancer increases, so it makes sense to screen all former smokers regardless of when they quit, explained Kim Lori Sandler, MD, from Vanderbilt University Medical Center, Nashville, Tennessee, and cochair of the American College of Radiology’s Lung Cancer Screening Steering Committee.
“There’s really nothing magical or drastic that happens at the 15-year mark,” Dr. Sequist agreed. For “someone who quit 14 years ago versus 16 years ago, it is essentially the same risk, and so scientifically it doesn’t really make sense to impose an artificial cut-off where no change in risk exists.”
The latest evidence reviewed in the new guidelines shows that expanding the guidelines would identify more early-stage cancers and potentially save lives. The authors modeled the benefits and harms of lung cancer screening using several scenarios.
Moving the start age from 55 to 50 years would lead to a 15% reduction in lung cancer mortality in men aged 50-54 years, the model suggested.
Removing the 15-year timeline for quitting smoking also would also improve outcomes. Compared with scenarios that included the 15-year quit timeline for former smokers, those that removed the limit would result in a 37.3% increase in screening exams, a 21% increase in would avert lung cancer deaths, and offer a 19% increase in life-years gained per 100,000 population.
Overall, the evidence indicates that, “if fully implemented, these recommendations have a high likelihood of significantly reducing death and suffering from lung cancer in the United States,” the guideline authors wrote.
But screening more people also comes with risks, such as more false-positive findings, which could lead to extra scans, invasive tests for tissue sampling, or even procedures for benign disease, Dr. Sandler explained. The latter “is what we really need to avoid.”
Even so, Dr. Sandler believes the current guidelines show that the benefit of screening “is great enough that it’s worth including these additional individuals.”