Factors associated with guideline-concordant biomarker testing in patients with stage IB-IIIA non-small cell lung cancer

Even with recent advances in identifying oncogenic genomic alterations and developing targeted therapies for non-small cell lung cancer (NSCLC), the uptake of molecular testing remains suboptimal among patients with advanced NSCLC, and comparable estimates for molecular testing in earlier stage NSCLC have not previously been published. This study describes and identifies factors associated with the receipt of 2021 guideline-concordant biomarker testing among patients with newly diagnosed stage IB-IIIA NSCLC within a community-based healthcare network. Methods: This was a retrospective cohort study of adult patients with histopathologically confirmed stage IB-IIIA NSCLC diagnosed within the Providence-Swedish Health Alliance between March 1, 2021, and June 3, 2022. The study outcome was defined as receipt of biomarker testing for somatic epidermal growth factor receptor (EGFR) mutations, concordant with 2021 National Comprehensive Cancer Network guidelines. Logistic regression analyses were performed to identify factors associated with receipt of guideline-concordant testing. Results: Of 322 patients, 70 (22%) received guideline-concordant EGFR mutation testing. Overall, the likelihood of receipt of guideline-concordant testing was similar across age, sex, health insurance, and stage categories. While none of the patients of minority races, Hispanic or Latino ethnicity, and/or who had a preferred language that was not English received guideline-concordant testing, small numbers limit conclusions. Of the 134 (42%) patients who underwent surgical resection of their NSCLC, 31 (23%) had guideline-concordant EGFR mutation testing versus 39 of 188 patients (21%) who had not undergone surgery. Among 22 patients whose resected tumor had been tested for one or more biomarkers, 9 (41%) received guideline-concordant EGFR mutation testing. The proportion of patients who underwent guideline-concordant testing was similar across Commission on Cancer-accredited cancer programs and facilities in metropolitan counties. However, none of the patients undergoing management at facilities in non-metropolitan counties received guideline-concordant testing. The proportion of patients who received guideline-concordant testing was higher at facilities with a reflex testing program (37%) compared to the proportion at facilities without a reflex testing program (15%). After multivariable adjustment, patients managed at facilities with a reflex testing program were 3.23 (95% confidence interval: 1.85-5.83) times as likely to undergo guideline-concordant EGFR mutation testing as compared to patients managed at facilities without a reflex testing program. Conclusions: This study highlights the suboptimal uptake of guideline-concordant EGFR testing in patients with early-stage NSCLC, notes potential disparities in testing, and underscores the importance of a reflex testing program in facilitating appropriate biomarker testing. These findings emphasize the urgency for interventions aimed at increasing awareness, addressing disparities, and improving access to guideline-concordant testing to optimize treatment decision-making.