Rate of Incidental Lung Nodule Follow-Up: A Cohort Study Evaluating Adherence to Guideline Recommendations

Computed tomography (CT) scans are used widely in clinical practice. Solitary pulmonary nodules (SPNs) are identified on thoracic imaging studies both incidentally and through lung cancer screening CT. The Fleischner Society guidelines provide a framework for follow-up of these incidental SPN. Adherence to follow-up for SPNs varies widely.1 Barriers to appropriate guideline-based follow-up can include forgotten incidental findings in patients admitted for extrapulmonary complaints and patient nonadherence, among other reasons. Current Fleischner Society guideline reports suggest that 51% of smokers over the age of 50 years have lung nodules identified on CT imaging.2 In nonsmokers, SPNs have a very low risk of malignancy, often quoted at a lower than 1% risk.2 Certain features of lung nodules raise suspicion for malignancy, including size greater than 8 mm, presence of spiculated margins, and inconsistent densities within the nodule.3 In SPNs that require follow-up, guidelines exist for appropriate follow-up intervals. In patients who are admitted, the follow-up recommendations are often described in CT imaging reports in compliance with Fleischner Society guidelines. However, whether guideline recommendations are mentioned in the radiology report and whether the report is compliant with guidelines varies on the basis of the reading radiologist.4 Assuming clear reporting of nodules and guideline-based recommendations, inpatient care must be translated to outpatient follow-up in a seamless process to ensure compliance. At a single metropolitan hospital in New York City, we sought to determine the rate of incidental lung nodule follow-up and to identify characteristics associated with increased adherence to follow-up. We describe patient demographic information, smoking status, cancer history, radiology reports, and nodule characteristics. We also collected information about prior imaging studies when present. Using these prior images, we were able to compare nodule size and characteristics to current imaging and identify the proportion of patients with enlarging nodules, placing them at higher risk. Methods We performed a retrospective review of patients admitted over a 6-month period in 2019. This study was exempted from Institutional Review Board review by the Northwell Health Human Research Protection Program, and informed consent was not required (HSRD20-0265, 08/10/2020). Patients who were at least 18 years of age, who had received thoracic CT scans during an in-patient admission to an academic-affiliated community hospital in New York City, and who had at least 1 solitary pulmonary nodule present were included in this study. CT imaging modalities included CT angiogram of the chest, noncontrast CT of the chest, and CT with IV contrast of the chest, which were performed for any indication. This study was not limited to CT chest imaging performed as part of lung cancer screening. Data related to patient demographics and characteristics, including smoking history, presence of emphysema, lung nodule characteristics, follow-up recommendations, and follow-up rates were collected. Data were collected by retrospective chart review from the electronic medical records (EMRs). Follow-up was determined by retrospective review of the EMRs as follows: when follow-up was noted to be “explicitly discussed at discharge,” the discharge physician and discharge summary presented the follow-up plan, which was concordant with the radiologist report recommendation; discharge summaries were reviewed for specific follow-up pulmonologist or primary care appointment; when patients presented for those follow-up appointments, those data were reviewed, when available. When available, follow-up appointment data were reviewed to identify outpatient follow-up, including imaging. The primary aim was to determine the rate of follow-up for identified pulmonary nodules. We analyzed characteristics of patients with lung nodules, factors associated with presence of lung nodules, factors associated with follow-up, and change in nodule size when compared to prior imaging.