The new guideline advises an annual screening test for lung cancer as a low-dose computed tomography scan, or low-dose CT scan.
“This updated guideline continues a trend of expanding eligibility for lung cancer screening in a way that will result in many more deaths prevented by expanding the eligibility criteria for screening to detect lung cancer early,” said Dr. Robert Smith, senior vice president of early cancer detection science at the American Cancer Society and the lead author of the new lung cancer screening guideline report.
Some context
Lung cancer is the overall leading cause of cancer death in the U.S., and it is the second-most frequently diagnosed malignancy in both men and women.
In 2023, researchers estimate 238,340 new cases of lung cancer—117,550 in men and 120,790 in women—will be diagnosed, with about 127,070 deaths from the disease—67,160 in men and 59,910 in women—according to the American Cancer Society.
“Recent studies have shown extending the screening age for persons who smoke and formerly smoked, eliminating the ‘years since quitting’ requirement, and lowering the pack-per-year recommendation could make a real difference in saving lives,” Smith said in the report.
Going forward
Dr. Fadi Abu-Shahin, oncologist with Houston Methodist Oncology Partners, said lung cancer is commonly associated with smoking, and the data backs that up. Roughly 90% of lung cancers are related to smoking, whether directly from smoking or exposure to secondhand smoke.
Expanding the age range for screenings gives physicians and patients an easier path to get insurance carriers to pay for the scans, whereas prior to the new guideline, they may have refused to cover the expense.
“This way, [with the new guideline] I have something that I can argue with the insurance company and say ... you should cover this scan for this patient,” Abu-Shahin said.
This updated guideline continues a trend of expanding eligibility for lung cancer screening in a way that will hopefully result in a greater prevention of deaths from the disease, as early detection is key, experts said.
“If we diagnose Stage 1 lung cancer and measure how many people will still be alive five years later, it's above 90%. So survival is pretty good for Stage 1. If you compare that to more advanced stages, 2, 3 and 4 ... which means that the lung cancer started in the lung but then spread outside the lungs, went to the liver, went to the brain,” Abu-Shahin said.
Who it affects
The degree of how heavy a smoker is depends on not just how many cigarettes or how many packs of cigarettes they smoke, but also how long they smoked. Oncologists use the term “pack year”—meaning the number of packs a person smokes per day multiplied by how many years they smoked.
For example, if they smoked one pack total for 20 years, they have a 20 pack year grade. If they smoked two packs for 10 years, that also equates to a 20 pack year status. In either case, that patient is considered at high risk to develop lung cancer.
“Especially in males, it is always in the top three cancers, regarding the incidence and the mortality, so it's relatively common and relatively fatal as well. So if you look at the data, it's one of the tough cancers overall, especially if it's found late,” Abu-Shahin said. “So you know, what we call the stage of the cancer, which is how early or advanced the cancer is ... the difference between each stage and [expected] survival is small, but for lung cancer it is huge.”
Why it matters
Researchers came up with the idea of using a low-dose CT scan based on studies conducted during the last 10 years and on over 80,000 subjects.
Abu-Shahin said that with that large number of patients with that level of smoking being scanned revealed clear evidence that resulted in close to 20% survival rate by detecting cancer early.
“So that's proven now that annual low-dose CT scan for the high-risk population was able to clip a drop in the mortality for lung cancer by close to 20%. That's huge for us. So because of that ... it became a clear recommendation that anybody with that high level of smoking should be screened annually.” Abu-Shahin said.
What else?
The minute amount of radiation used in the low-level scans poses a minimal risk to patients from the cumulative effect of annual scans. The ratio of cancer discoveries versus effects of radiation was 108 to 1—meaning 108 patients' cancers were detected, Abu-Shahin said.
“So it's a pretty clear benefit over risks ... the numbers increase every year of how many scans get done [and] ...we want people to know that if you are a smoker, come forward,” Abu-Shahin said.
