Community-Based Lung Cancer Screening Adherence to Lung-RADS

By Sarah LaCorte


Lung cancer screening with low-dose computed tomography (LDCT) is recommended for high-risk smokers who meet specific eligibility criteria. Current guidelines suggest that eligible adults with a heavy smoking history will benefit from annual LDCT. The NLST and NELSON clinical trials demonstrated that lung cancer screening with low-dose CT reduces lung cancer-specific mortality. Now, researchers have determined adherence to Lung-RADS recommendations among community-based patients undergoing lung cancer screening in a study presented at the ASCO 2021 Annual Meeting (Abstract 10540).

In the NLST and NELSON trials, most LDCT screen-detected lung cancers were not diagnosed during the first round of screening.

“Importantly, both trials had multiple rounds of screening and the majority of screen detected lung cancers were diagnosed after the baseline screening period, suggesting that a longitudinal approach to screening is crucial,” said Roger Kim, MD, a pulmonary clinical care fellow at the University of Pennsylvania, who presented the research. “Moreover, adherence rates in the clinical trial setting were noted to be greater than 90 percent.”
Kim said that, while prior single-center studies have assessed lung cancer screening adherence, they have been limited by lack of generalized ability and inconsistent definitions of adherence.

“Therefore, our objectives were to determine the adherence to Lung-RADS recommendations among real-world community-based patients undergoing lung cancer screening across multiple health care systems and to evaluate patient characteristics associated with adherence,” Kim said. “We performed a multicenter retrospective cohort study of patients screened for lung cancer at health care systems within the lung Population-based Research to Optimize the Screening Process Research consortium (PROSPR).”

The study included 55- to 80-year-old current or former smokers who received a baseline (T0) LDCT with a Lung-RADS score between January 1, 2015, and September 30, 2017, and excluded patients who were diagnosed with lung cancer prior to the T0 scan.

“We excluded patients who were diagnosed with lung cancer prior to their baseline scans. And for those who are diagnosed with lung cancer or died during the period of adherence ascertainment, our primary outcome was adherence to Lung-RADS recommendations,” Kim said. “For example, patients with a baseline Lung-RADS for one or two scans were considered to be adherent If they had a follow-up CT chest within 9-15 months after the baseline scan, while patients with a Lung RADS 4B or 4X scan were deemed to be adherent if they had any imaging or diagnostic procedure within three months of the baseline scan.”

Over a 24-month period, Kim and colleagues calculated the proportion of patients adherent to Lung-RADS recommendations and evaluated associations with patient-level, including age, sex, race, ethnicity, smoking status, body mass index, Elixhauser comorbidities, year of T0 scan, Lung-RADS score, and census tract data. They used multivariable logistic regression with mixed effects to account for site variability.

The study cohort included 6,723 patients with a median age 65 years (45.1% female; 73.0% white). Fifty-nine percent were current smokers and 5,583 (83.0%) had Lung-RADS 1 or 2 T0 scans, 733 (10.9%) Lung-RADS 3, 274 (4.1%) Lung-RADS 4A, and 133 (2.0%) Lung-RADS 4B or 4X.

“Overall 57.3 percent of patients were adherent to Lung-RADS recommendations, unadjusted univariate analysis revealed that adherence significantly differed by all covariates of interest,” Kim said. “For example, we observed 50.2 percent adherence among 55- to 60-year-old patients compared to 63.7 percent among 70- to 75-year-old patients. While an adherence rate of 59.5 percent was observed among White patients, a lower adherence rate of 34.4 percent was observed among Black patients. A 76.3 percent adherence was observed among patients screened within centralized programs compared to only 39.4 percent at decentralized programs.”

A greater adherence was observed in former smokers compared to current smokers (aOR 1.33, 95% 1.19-1.49). Compared to individuals with a negative T0 scan (Lung-RADS 1 or 2), those with Lung-RADS 3 (aOR 1.56, 95% CI 1.31-1.86), 4A (aOR 1.63, 95% CI 1.24-2.15), or 4B/4X (aOR 3.59, 95% CI 2.30-5.60) T0 scans had greater odds of adherence.

“Decreased adherence was observed in patients of Black race or Hispanic ethnicity compared to non-Hispanic White patients; even after adjusting for other covariates, our results reveal reduced lung cancer screening adherence compared to clinical trials and underscore the need for further study of system-level mechanisms to improve longitudinal lung cancer screening adherence rates,” Kim concluded.

The authors said in conclusion that the results highlight the need for further study of system-level mechanisms to improve longitudinal LCS adherence rates.

Sarah LaCorte is associate editor.​