GoKawiilAt 69, Melinda McKnight is as busy as ever. In the past year, she has organized several fundraising events around her hometown of Rison, Arkansas, and purchased Christmas presents for more than 100 local children as part of a charity she co-founded. She often looks after two of her six grandchildren. None of this would be possible if the stage 1 cancer in her right lung hadn’t been caught three years ago.
“I was blessed in so many ways,” McKnight says. In 2015, she heard that her employer would cover the cost of lung cancer screening. Her physician scheduled a low-dose computed tomography (CT) scan, which revealed a small lung nodule. Initially, the lump didn’t meet the criteria for cancer. But McKnight returned for annual scans, and in 2023, a scan revealed that the nodule had begun to grow. Within months, she had surgery to remove the early-stage tumour. Today, she has no evidence of disease.
Nature Outlook: Lung cancer
McKnight’s story could have been very different. The contrast between treating people with early compared with advanced disease “couldn’t be more striking”, says Jeffrey Chi-Fu Yang, a thoracic surgeon at Massachusetts General Hospital in Boston. When diagnosed at stage 1, 60–90% of people with lung cancer will still be alive after five years. That statistic drops as much as tenfold at the latest stages of disease.
This stark difference shows the potential that screening has to save lives. Among people with a history of heavy smoking, annual low-dose CT scans reduced the chance of death from lung cancer by 20% over six years in one study1 and by 24% over ten years in another2. Low-dose CT, which uses one-fifth of the radiation dose of conventional CT, has stronger evidence behind it than any other cancer-screening test, says Raymond Osarogiagbon, an oncologist at Baptist Cancer Center in Memphis, Tennessee.
In 2013, the US Preventive Services Task Force (USPSTF) started recommending screening for some people with a history of heavy smoking. In 2015, Medicare, the US federal health-insurance programme for people aged 65 and over, began covering the test for those eligible. But more than a decade later, only a fraction of these people are screened. A survey study funded by the American Cancer Society found that just 19% of people who meet the criteria have ever had the scan3.
Meanwhile, about half of people who are diagnosed with lung cancer have never met the USPSTF criteria — they were outside the age range, smoked too little or stopped smoking too long ago. “We know the criteria are not perfect,” says Osarogiagbon. “They weren’t cast stone tablets and handed down,” he says. Some researchers suggest that the best way forward is to eliminate smoking history from the criteria. “We in the United States need to figure out quickly how to thoughtfully screen people who have never smoked,” Yang says.
But it’s not clear whether the benefits of screening people who have never smoked will ever be large enough to justify the risks. Benign lung nodules are common, and expanding screening will inevitably result in more people undergoing unnecessary biopsies, which come with the risk of bleeding and lung collapse. Less invasive diagnostics, such as blood-based biomarkers and artificial-intelligence image analysis, could shift this risk–benefit debate. “We’ll have to innovate our way out of this,” Osarogiagbon says.
McKnight’s primary-care physician was eager to get her screened. But another physician was sceptical. “He looked at me and said, ‘well that’s a bit of overkill, don’t you think?’”
Underused and misunderstood
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