Precision medicine in advanced non-small cell lung cancer (NSCLC) requires molecular biomarker testing in patients with non-squamous and select patients with squamous histologies, and PD-L1 testing in both.What are rates of molecular and PD-L1 biomarker testing in patients with advanced NSCLC in community practices and do rates vary by sociodemographic factors? What is the prevalence of molecular biomarker mutations and PD-L1 expression levels?From 389 stage IV NSCLC pathology reports obtained through the UNC Lineberger Comprehensive Cancer Center's Rapid Case Ascertainment Program from 38 community hospitals across North Carolina, we abstracted demographics, histology, molecular biomarker testing and results, PD-L1 testing and expression. We geocoded patient and hospital addresses to determine travel time, distance to care, and census block level contextual variables. We compared molecular biomarker and PD-L1 testing rates, the prevalence of molecular biomarkers, and PD-L1 expression levels by race and sex using chi-square tests. We determined predictors of testing using multivariable logistic regression and report adjusted odds ratios (aOR) and 95% confidence intervals (95%CI).Among patients with non-squamous NSCLC, 64.4% were tested for molecular biomarkers and among all NSCLC patients 53.2% were tested for PD-L1 expression. Differences in biomarker testing rates by sociodemographic factors were not statistically significant in univariate or adjusted analyses. Adjusted analyses showed patients living in areas with higher household internet access were more likely to undergo PD-L1 testing (aOR=1.66, 95%CI:1.02-2.71). Sociodemographic differences in molecular biomarker prevalence and PD-L1 expression levels were not statistically significant, except for HER2 mutations which occurred in 16.7% of males vs. 0% in females, p=0.05.Biomarker testing remains underutilized in NSCLC. Future work should include larger populations and evaluate hospital-specific testing protocols to identify and address barriers to guideline-recommended testing.
M Patricia Rivera, Marjory Charlot, Danielle D Durham, Allison Throneburg, Lindsay M Lane, Pasangi Perera, Teresa D Samulski, Louise M Henderson