Abstract D134: Patterns of EGFR mutation testing among patients with metastatic lung cancer in a safety-net hospital

Background: Lung cancer is the second most common cancer and the first leading cause of cancer death in the United States. EGFR mutations are the second most common oncogenic driver mutation which occur in up to 23% of advanced lung adenocarcinoma (LAC) cases. These are seen with increased frequency in women, never smokers, and those of Asian ethnicity, affecting up to 50% of Asian patients. Since 2011 NCCN guidelines have recommended EGFR testing for all patients with newly diagnosed metastatic LAC. Despite guideline recommendations, population-based studies have shown underutilization of guideline-recommended EGFR testing and identified racial, economic, and regional disparities in testing. We aimed to review adherence patterns with guideline-recommended EGFR testing at our city’s only safety-net hospital. Methods: We performed a retrospective review of all patients diagnosed with metastatic LAC between 2011 and 2015 at Zuckerberg San Francisco General (ZSFG) Oncology Clinics. The ZSFG Cancer Registry was queried to identify patients and collect demographic information, including race, and EGFR mutation status. Electronic medical records were reviewed to confirm the diagnosis of metastatic LAC and EGFR mutation status based on pathology and molecular testing reports. Data analysis was performed using descriptive statistics. Results: We identified 110 patients with metastatic LAC diagnosed between 2011 and 2015 at ZSFG Oncology Clinics. The racial composition of the cohort represented the diversity of our patient population, with 31.8 % White (n=35), 26.4 % African American (n=29), 37.3 % Asian (Chinese n=26, Filipino n=10, and other Asians n=5), and 4.5 % unknown (n=5). Seventy-one patients (64.5 %) underwent molecular testing for EGFR mutation, thirty-four (30.9 %) were not tested, and five patients (4.5 %) were deemed not candidates for molecular testing as per NCCN guidelines. Among those who were tested for EGFR mutation, 35.2% (n=25) harbored an EGFR mutation. Eighty percent (n=20) of EGFR mutant patients were of Asian race, 16% (n=4) White, and 4% (n=1) African American. Eight patients (23.5 %) did not undergo molecular testing due to insufficient or inadequate samples. Conclusions: Despite guideline recommendations for EGFR testing, our study identified that there is widespread underutilization of guideline-recommended testing at our institution, as well as limitations in tissue sampling adequacy for molecular testing. These represent significant barriers to providing guideline-concordant care to our underserved patient population. As a result, the ZSFG Cancer Committee established a quality task force that has newly implemented the following interventions: (1) multidisciplinary evaluation of all new diagnosis of non-small cell lung cancer, and (2) standardized EGFR testing as part of a 4-gene mutation panel adherent with guideline recommendations. Citation Format: Ana I Velazquez, Niharika Dixit. Patterns of EGFR mutation testing among patients with metastatic lung cancer in a safety-net hospital [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D134.