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
“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
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
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.