‘It can save their lives’: Annual lung cancer screening improves cancer detection rate

Key takeaways:

• Adults who adhered to lung cancer screening had a higher diagnosis rate vs. those who did not.
• Early-stage lung cancer was diagnosed at a significantly higher rate among those who adhered to screening.

Annual lung cancer screening, or LCS, detects cancer at a higher rate and at earlier stages, findings suggest.

According to Roger Y. Kim, MD, MSCE, DAABIP, ATSF, an assistant professor of medicine at the Hospital of the University of Pennsylvania, LCS with low-dose CT “has not been as effectively publicized or implemented in the United States as other cancers [have], such as colorectal, breast or prostate cancer.

“Adherence to annual LCS has been suggested as a quality metric for screening programs because in large randomized clinical trials, most lung cancers were diagnosed during follow-up rounds of screening,” he told Healio. “However, previously there was no concrete real-world data that linked adherence across multiple rounds of screening to improved early-stage lung cancer detection rates.”

In the retrospective cohort study, Kim and colleagues examined data from 10,170 adults aged 55 to 75 years who had undergone an initial LCS between Jan. 1, 2015, and Dec. 31, 2018, in one of five health care systems.

LCS adherence among people who received positive results at the initial screening (T0) was defined as a chest CT conducted between 10 to 18 months (T1) and 22 and 30 months (T2) after the baseline LCS.

T1 and T2 screening adherence for people with negative results at T0 were defined as a chest CT conducted between 11 and 21 months and 28 and 36 months after the initial screening, respectively.

Adherence waned but still helped detection

The researchers found that LCS adherence dropped from 61.2% (95% CI, 60.2%-62.2%) at year 1 to 50.5% (95% CI, 49.5%-51.4%) at year 2.

Overall, 2.7% (95% CI, 2.4%-3.1%) of patients were diagnosed with lung cancer during the 36 months of follow-up, with a higher proportion diagnosed among those with positive vs. negative LCS results at baseline (12.1% vs. 1%).

The researchers reported that the rate of incident lung cancer diagnosis was:

• 1.3% (95% CI, 1.1%-1.6%) from 0 to 12 months after baseline (round T0);
• 0.7% (95% CI, 0.5%-0.8%) from over 12 to 24 months after baseline (round T1); and
• 0.8% (95% CI, 0.6%-0.9%) from over 24 to 36 months after baseline (round T2).

The rates of lung cancer diagnosis were higher among people who adhered to LCS compared with those who did not during rounds T1 (1% vs. 0.2%) and T2 (1.3% vs. 0.2%).

Meanwhile, a larger proportion of early-stage lung cancers were diagnosed during round T2 among people adherent to T2 screening vs. those who were not (73% vs. 25%).

Kim and colleagues noted that the associations between LCS adherence and lung cancer diagnosis remained during rounds T1 (adjusted RR = 4.64; 95% CI, 2.57-8.37) and T2 (adjusted RR = 5.9; 95% CI, 3.34-10.43) in multivariable analyses, but T1 adherence was not tied to lung cancer diagnosis during round T2.

Tracking adherence of ‘critical importance’

Kim noted that the findings “emphasize the critical importance of measuring and tracking longitudinal adherence to annual LCS.”

“It is clear that getting high-risk patients enrolled in a screening program is no longer enough,” he said to Healio. “Programs must additionally allocate sufficient resources to ensuring that patients come back for their annual screens in order to fully realize the potential benefits that lung cancer screening can provide to promote early detection of lung cancer and, ultimately, reduce lung cancer mortality.”

He highlighted the fact that one in 16 Americans will be diagnosed with lung cancer in their lifetime, “and nearly everyone in the country personally knows someone impacted by lung cancer.

“The public needs to understand the importance of LCS and make sure that they or their loved ones who are eligible for screening get screened,” Kim added. “It really can save their lives.”

For more information:

Roger Y. Kim, MD, MSCE, DAABIP, ATSF, can be reached at roger.kim@pennmedicine.upenn.edu.