Amid the rush of enthusiasm for CT lung cancer screening, a new study published in JAMA Health Forum offers a cautionary note. Researchers found that in the real world, people eligible for lung screening were sicker than those in research studies, and thus may not enjoy screening’s benefits to the same extent.
Support for CT lung cancer screening is based on randomized controlled trials published in 2011 (NLST) and NELSON (2020) that showed screening reduced lung cancer mortality among high-risk individuals who typically had long smoking histories.
- The studies have spurred momentum for large-scale CT lung cancer screening programs, with a number of European and Asian countries starting national initiatives.
But how generalizable are these results? Researchers noted that people who participated in the NLST study tended to be younger and healthier than individuals who qualify for screening in the real world.
- Co-morbidities like COPD, diabetes, and heart disease, as well as age and racial background, can have an impact on survival after treatment for lung cancer, and thus could reduce screening’s risk/benefit calculation.
In the new Personalized Lung Cancer Screening study, researchers analyzed the comorbidity profiles of 31.8k people who got screened between 2016 and 2021 in California, Florida, and South Carolina.
- They noted that their PLuS study cohort was more diverse in terms of age, race, and ethnicity than that used in NLST, and potentially had more comorbid conditions.
In analyzing their population, PLuS researchers found that compared to NLST participants, people screened in their real-world programs had …
- Higher rates of COPD (33% vs. 18%).
- Higher rates of diabetes (25% vs. 9.7%).
- Higher rates of heart disease (16% vs. 13%).
- Were more likely to be aged 70 and over (25% vs. 8.8%).
- Had high scores on various metrics of comorbidity and frailty.
Older, sicker patients are less likely to have good health outcomes after lung cancer surgery, and might also succumb to conditions like COPD, diabetes, and heart disease before lung cancer, which could also reduce lung screening’s benefits.
The Takeaway
While the new findings aren’t likely to seriously dampen CT lung cancer screening’s growing momentum, they do illustrate a point that should always be kept in mind when looking at research results: in the real world, your mileage may vary.
