An additional 5 million Americans who smoke or used to smoke should undergo annual screenings for lung cancer — the No. 1 cancer killer in the United States — according to an updated guideline issued Wednesday by the American Cancer Society.
The broadened recommendations apply to about 19 million people who the cancer group said would benefit from yearly low-dose computed tomography scans. CT scans provide detailed images of the lungs, allowing for improved cancer detection at an earlier stage, when the disease is more treatable.
In the biggest change, the new guideline recommends that people continue to get annual scans even if they stopped smoking more than 15 years ago. The previous recommendation, issued a decade ago, said people should discontinue screening 15 years after quitting smoking. Under the new guidance, those who stopped getting scans after 15 years should resume getting screened, the cancer society said.
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The new guideline, published in the cancer society’s journal, CA: A Cancer Journal for Clinicians, also recommends screening for people 50 to 80 years old. The previous guidance applied to ages 55 through 74.
Robert Smith, senior vice president for early cancer detection science at the cancer society and lead author of the guideline, said the change reflects the fact that lung cancer risk continues to rise as former smokers age, no matter how long it has been since they quit smoking. The risk remains ‘’quite high,’’ though it is lower than if smokers had continued to smoke, he added.
In addition, the guideline was broadened to include people with a less intense smoking history. The new recommendation applies to people who smoke or used to smoke the equivalent of one pack of cigarettes a day for 20 years. The previous guideline was for people who smoked the equivalent of one pack of cigarettes a day for 30 years.
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The mortality rate for lung cancer has declined sharply in recent decades because of plummeting smoking rates, but the health toll remains high. In 2023, the cancer society estimates, there will be about 238,000 new cases of lung cancer in the United States and more than 127,000 deaths, accounting for 20 percent of all cancer fatalities. Cigarette smoking is the main cause, responsible for about 80 percent of cases.
‘’We face an enormous challenge in reducing lung cancer deaths, but we have better opportunities than in the past’' because of CT scans and medications such as immunotherapy, Smith said. Immunotherapy, which has emerged in recent years as an important cancer treatment, marshals the immune system to attack malignancies.
Experts emphasize the importance of detecting lung cancer before it spreads. The five-year survival rate for non-small-cell lung cancer, the most common type of lung cancer, is 65 percent for patients in which the cancer has not spread outside the lung, according to the cancer society. The survival rate is 37 percent for cancer that has spread to nearby parts of the body or lymph nodes and only 9 percent for cancer that has spread to more distant parts of the body, such as the brain, bones, liver, or the other lung.
Julie Barta, assistant professor and lead for the Lung Cancer Screening Program at Thomas Jefferson University Hospitals in Philadelphia, called the new version a ‘’really important step forward’' in the effort to reduce lung cancer deaths.
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Barta, who was not involved in developing the cancer group’s updated guideline, praised the recommendation that former smokers continue to undergo screening beyond 15 years after quitting. She said the change reduces the kind of complexity that can be a barrier to screening.
The new guideline is in closer alignment with the recommendations of the United States Preventive Services Task Force, an independent panel of experts that assesses the effectiveness of preventive health care. Because the task force endorses annual lung cancer screening, most insurers must cover it without imposing cost-sharing on patients.
The task force’s recommendations differ from the cancer group’s guideline in at least one way, however: They call for an end to screening once a person has not smoked for 15 years.
Lung cancer screening carries some risks, though experts say they are outweighed by the benefits. Sometimes CT scans produce false positives, which can lead to unnecessary follow-up tests and surgery. But Smith said the problem has declined in recent years and that the current rate of false positives is about the same as for mammograms.
Over-diagnosis is another risk of screening. That occurs when a tumor is found that never would have posed a threat to the patient but is treated anyway, with some drugs taking a significant toll on the body.
The cancer society’s Smith acknowledged the uptake of lung cancer screening in recent years has been disappointingly low. While the rate varies from state to state, the national average is only about 10 percent of those who are eligible — ‘’not remotely as high’' as is needed, he said.
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Even when people get a CT scan, they often don’t return the following year, he said.
‘’I don’t think they fully appreciate it is not one-and-done,’’ Smith said. ‘’They probably think they have a high risk of lung cancer, and find out they don’t have it, so good. They don’t get a clear message that this is like screening for breast cancer,’’ which involves annual mammograms.
‘’We have to do a much better job of reminding them they are due for their examination.’’