CT Lung Cancer Screening Underperforms with Participation and Detection

Screening patients at high risk for lung cancer may not be beneficial, even though population-based low-dose CT screening programs have been launched globally to increase detection rates.

At least that is what a team of investigators from China found in a six-year study that was initially intended to assess both the participation and detection rates of a screening initiative in the country. Not only did they find the compliance rate with undergoing screening was low, but they also discovered there is no statistically significant difference in cancer detection rates between patients who were screened and those who were not – 0.35 percent versus 0.38 percent, respectively.

The team, led by Lan-Wei Guo, Ph.D., from the Henan Cancer Hospital and The Affiliated Cancer Hospital of Zhengzhou University, published their results, based on an analysis of CT scans captured between October 2013 to October 2019, in the Nov. 3 JAMA Network Open.

Worldwide, low-dose CT screening for lung cancer is known to be an effective strategy for cancer detection and reducing mortality. In fact, the National Lung Screening Trial (NLST) determined, in 2011, that CT screening created a 20-percent drop in mortality when compared with X-ray screening. That impact can be a game-changer in China where lung cancer survival rates are only 19.7 percent and mortality rates have skyrocketed by 465 percent in the past three decades.

Related Content: Low Dose CT Lung Cancer Screening Program Findings Similar to National Trial​

To reach that goal, in October 2012, the National Health Committee of China launched the Cancer Screening Program in Urban China (CanSPUC) to target six types of cancer that were most common in urban areas, including lung cancer, female breast cancer, esophageal cancer, gastric cancer, colorectal cancer, and liver cancer. Guo’s team evaluated how effective CanSPUC has been compared to existing American and European lung cancer screening programs.

CanSPUC relies on a risk score to pinpoint which people should undergo low-dose CT screening. Overall, for this study, Guo’s team identified 282,377 individuals between ages 40 to 74 from eight cities qualified for screening, but only 55,428 met the risk criteria and were included. And, of those enrolled, only 22,260 – 40 percent – actually followed through and got the screening study. For the study, all participants underwent low-dose CT scans with a 16-section multi-detector CT scanner. No subsequent imaging was conducted.

The researchers conducted their follow-up after six years in March 2020. In their analysis, they found 78 cancer cases in study participants who were screened, but they found 125 in patients who were not, producing a 0.93 odds ratio of a cancer being identified.

Low program participation from high-risk individuals could be the reason behind the lack of statistical significance, the team said. They noted that the NLST participation rate is 95 percent, but the rate of actual screening is lower. The National Health Interview Survey, conducted in 2015, only 260,000 of 6.8 million eligible patients – 3.8 percent – actually received the low-dose screening.

“The poor compliance with [low-dose CT] screening appears to be a common problem in real-world [low-dose CT] screening programs involving large sample populations,” the team said.

Of the patients, the team determined women, former smokers, and patients who have a family history of lung cancer were more likely to get screened, and men were more likely to get a cancer diagnosis. They also postulated that screening rates could also have been impacted by long time spans between enrollment to screening, distance to screening locations, and low awareness of screening.

Ultimately, the team said, their findings could play a beneficial role in improving screening across populations.

“Our results suggest that public awareness campaigns are necessary to improve the participation rate of lung cancer screening in the future,” they said.

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