SESSION TITLE: Lung Cancer
SESSION TYPE: Original Investigation Slide
PRESENTED ON: Tuesday, October 28, 2014 at 02:45 PM - 04:15 PM
PURPOSE: As part of the Choosing Wisely Campaign, the Society of Thoracic Surgeons recommends avoiding brain imaging in asymptomatic patients with early-stage non-small cell lung cancer (NSCLC). We aimed to describe variations in brain imaging among National Lung Screening Trial (NLST) participants diagnosed with stage I NSCLC, and to identify factors associated with receipt of brain imaging.
METHODS: Using NLST data, we identified patients with clinical stage IA or IB NSCLC. Our outcome was computed tomography (CT) or magnetic resonance (MR) brain imaging performed within 60 days after the diagnosis of NSCLC but before the establishment of a definitive pathologic stage. Explanatory variables included patient demographic characteristics, clinical stage, tumor size, and enrollment at an American College of Radiology Imaging Network (ACRIN) site. We performed bivariate analyses using unpaired t-test and chi-squared test for continuous and categorical variables, respectively. Using multivariate logistic regression, we identified variables and any interactions that were associated with undergoing brain imaging with a significance of level of p<0.05.
RESULTS: There were 783 patients with clinical Stage IA (n=656; 84%) or IB (n=127; 16%) disease. 170 patients (22%) received at least one brain imaging study within 60 days of their diagnosis, and a total of 11 patients (1.4%) who underwent brain imaging were upstaged to Stage IV disease. In bivariate analyses, larger tumor size (>20mm) [OR 2.37 (95% CI 1.68 - 3.36), p<0.001] was associated with greater use of brain imaging, while enrollment at an ACRIN site was associated with less imaging [OR 0.44 (95% CI 0.25 - 0.77), p<0.01], but only among patients with tumor size >20mm. After multivariate adjustment, tumor size, enrollment at an ACRIN site, and a size-ACRIN site interaction were associated with use of brain imaging.
CONCLUSIONS: Among patients with early-stage NSCLC who participated in the NLST, over one-fifth underwent brain imaging, but very few ultimately had metastatic disease, a finding consistent with those in prior studies. Larger tumor size and enrollment at a non-ACRIN site were associated with greater use of brain imaging. It is unknown whether institution-specific factors or patient-clinician factors drive this difference, and further studies are warranted.
CLINICAL IMPLICATIONS: By understanding the overuse of brain imaging in Stage I NSCLC despite the infrequency of occult metastases, clinicians can decrease unnecessary tests and lower costs.
DISCLOSURE: The following authors have nothing to disclose: Alex Balekian, Joshua Fisher, Michael Gould
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