Clinical outcomes of patients with early-stage epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer who underwent reflex molecular testing.

Abstract

e20531 Background: One-third of patients with newly diagnosed non-small cell lung cancer (NSCLC) present at an early stage. Surgical resection remains the standard of care for medically fit patients. Adjuvant chemotherapy has shown benefit in stage II and III disease, but with the advent of immune checkpoint inhibition and targeted therapy, the adjuvant setting is now evolving. In 2017, all hospitals in the Houston Methodist Hospital (HMH) system approved reflex molecular testing at the time of diagnosis for all new cases of NSCLC, regardless of the clinical or pathologic stage. We performed a retrospective analysis of patients with NSCLC who underwent reflex molecular within the HMH system. Here we report outcomes for patients with early-stage EGFR-mutated NSCLC. Methods: Data was collected from a network of 7 hospitals for patients who underwent reflex molecular testing from 1/1/2017 to 8/31/2022. Patients diagnosed with stage I-II NSCLC and molecularly confirmed EGFR mutations were included. Baseline characteristics included age at diagnosis, sex, race, smoking status, performance status, and comorbidities. Pathologic assessment included histologic subtype, molecular results, and time from diagnosis to results of reflex molecular testing. Treatment information included initial surgery, radiation, and adjuvant therapy if given. Recurrence free survival (RFS) and overall survival (OS) were reported using Kaplan Meier methodology. Results: There were 37 patients included, with a median age at diagnosis of 71.2 (48-85) years. Of these, 26 (70.3%) were females, 21 (56.8%) were non-Hispanic Caucasian, and 16 (43.2%) were current/former smokers. All cases were histologically confirmed adenocarcinoma and 29 (78.4%) were stage I disease. Thirteen (35.1%) patients had exon 19 deletion, 17 (45.9%) had exon 21 L858R, and 3 (8.1%) had two synchronous EGFR mutations. Median time from diagnosis to EGFR results was 18 (5-134) days. Reflex test resulting time from 2017-2018 and 2019-2021 was 22 (5-134) and 16 (8-96) days, respectively. Thirty-four (91.9%) patients who underwent surgical resection and 3 (8.1%) received radiation. Five (13.5%) patients received adjuvant chemotherapy and 5 (13.5%) received EGFR-targeted therapy. At last follow-up, 7 (18.9%) patients had recurred and 4 (10.8%) died. RFS at 3 and 5 years was 68.2% and 56.9%, respectively. OS at 3 and 5 years was 88.7% and 82.8%, respectively. Conclusions: Reflex molecular testing at our institution has allowed for insight into outcomes of patients with early-stage NSCLC harboring EGFR mutations. With the adjuvant landscape evolving, broader adoption of reflex molecular testing in early-stage lung cancer should be implemented. Our analysis shows improvement in resulting time for molecular testing, along with similar DFS and OS reported in other studies.