Study Evaluates Factors Affecting Patient Adherence to Lung-RADS Screening Intervals

Patients with second screening that shows unchanged or downgraded category less likely to return for future screenings

Lin Yannan

Physician reminders and patient education are critical to overcoming barriers to lung cancer screening (LCS). This is particularly true for ensuring screening adherence over time in patients who may become complacent following two negative screens or who received a downgraded score from a previously positive screen.

In a session presented at RSNA 2022, Yannan Lin, MD, MPH, a PhD candidate in the Medical Imaging and Informatics Section of the University of California, Los Angeles (UCLA), and her colleagues investigated whether changes in patient Lung CT Screening Reporting & Data System (Lung-RADS) scores were associated with adherence to the follow-up recommendations outlined within the Lung-RADS system.

Lung-RADS, first introduced in 2014 by the American College of Radiology, was designed to standardize lung cancer screening CT reporting and management recommendations. Screening intervals outlined in the system are based on recommendations that vary according to levels of suspicion for malignancy of detected pulmonary nodules.

Dr. Lin said that despite promising adherence rates of over 90% in prior clinical trials, adherence rates to Lung-RADS recommendations in clinical practice proved to be far lower.

“Low adherence to lung cancer screening in real-world clinical practice diminishes the mortality benefit of annual screening derived from the clinical trial,” she said.

“We found that Lung-RADS score was a significant factor affecting adherence to baseline Lung-RADS recommendations and we also found that lower adherence among patients occurred more often with a negative screen (Lung-RADS 1 or 2) than a positive screen (Lung-RADS 3 or 4).”


Factors That Affect Adherence To Lung Screenings

To better understand which factors contribute to low adherence in clinical LCS programs, Dr. Lin and her colleagues published a systematic review and meta-analysis in the Journal of Thoracic Oncology in 2021.

“We found that Lung-RADS score was a significant factor affecting adherence to baseline Lung-RADS recommendations,” Dr. Lin said. “Lower adherence among patients occurred more often with a negative screen (Lung-RADS 1 or 2) than a positive screen (Lung-RADS 3 or 4).”

Watch Dr. Lin discuss her research: 

Working with co-investigators Li-Jung Liang, PhD, Denise R. Aberle, MD, William Hsu, MD, and Ashley Elizabeth Prosper, MD, Dr. Lin sought to determine whether changes in Lung-RADS scores could be associated with adherence to Lung-RADS recommendations.

The team conducted a study that included the records of patients at UCLA who underwent their first two lung screenings between July 31, 2013, and Nov. 30, 2021, with their last follow-up date through Dec. 8, 2021.

The researchers evaluated patient adherence, which they defined as completion of a recommended or a more invasive follow-up exam according to Lung-RADS score. For the purposes of their analysis, adherence to recommendations was considered 15 months for patients with a Lung-RADS score of 1 or 2, nine months for a Lung-RADS score of 3, and five months for a Lung-RADS score of 4A.

The patients were categorized into subgroups based on their Lung-RADS scores from the first two examinations: unchanged [624 negative (Lung-RADS 1 and 2), 26 positive (Lung-RADS 3 and above)], upgraded (from negative to positive), and downgraded (from positive to negative).

Among the 794 eligible patients, the researchers found that 82% were in the unchanged category, while 7.7% and 10.4% were in the upgraded and downgraded categories, respectively.

“After adjusting for baseline patient demographics, socioeconomic status and health status, we found the odds of being adherent to the Lung-RADS recommendations at second screening decreased in both the unchanged-negative category and the downgraded category,” Dr. Lin said. “Patients in the upgraded category showed a significant increase in the second Lung-RADS recommendation adherence.”

They found no significant change in adherence among patients in the unchanged-positive category.

Patient demographic factors and socioeconomic status were not significantly associated with non-adherence. However, Dr. Lin said that the results have not been validated externally using multi-center data.

Dr. Lin acknowledged a limitation in capturing changes in Lung-RADS scores within the positive screening group.

“For example, a Lung-RADS 3 interpretation followed by a Lung-RADS 4A interpretation was considered unchanged in this analysis because they were both positive screens, yet the level and likelihood of cancer have both increased,” Dr. Lin said.

Since then, the researchers have looked at modeling changes more granularly, for example defining Lung-RADS 3 to Lung-RADS 4 as upgraded and Lung-RADS 4 to Lung-RADS 3 as downgraded, and are actively collecting data to perform the more detailed analysis. In addition, Dr. Lin said that she and her colleagues plan to seek collaborations to work toward multicenter studies.

Looking at Lung Cancer Screening Barriers

According to Dr. Lin, the LCS program at UCLA has implemented interventions to address screening barriers at the physician level and plans to look at additional patient-level barriers. She noted that at UCLA Health, the LCS team sends email reminders to the patients’ referring physicians to alert them when their patients’ screenings are due. The recommendations play an important role in influencing patient adherence to cancer screening recommendations.

The team have also found that many of their LCS participants are lost to follow-up after their baseline screening—a challenge faced by many practices. Dr. Lin said that this problem occurs because patients may lack an awareness that lung cancer screening is not a one-time event, but rather a process that should occur annually for the duration of the individual’s eligibility.

“Stronger emphasis is needed on patient education, physician education, reminders and community outreach to ensure patients return for the repeat screening exams,” Dr. Lin said.

For More Information

Access the Journal of Thoracic Oncology at

Read previous RSNA News articles on lung cancer screening: