Real-world treatment patterns and clinical outcomes in EGFR-mutant unresectable locally advanced NSCLC (LA-NSCLC): A retrospective multicenter study of 367 patients.

Abstract

9047 Background: The chemoradiation therapy (CRT) is the standard care for unresectable LA-NSCLC. The addition of EGFR-TKIs in first-line treatment of EGFR-mutant subpopulation is debatable. Methods: We retrospectively collected data for patients with unresectable stage III NSCLC harboring EGFR mutations from nine major academic cancer institutions in China from Jan 2012 to December 2018. Patients with ALK rearrangements were excluded. Patients were categorized into three subgroups according to the primary treatment: 1) RT+TKI: Combined RT and EGFR-TKI with/out chemotherapy; 2) no TKI: CRT alone; 3) upfront TKI: EGFR-TKI followed by RT at local-regional progression. PFS and OS were calculated from the date of diagnosis. Log-rank test was used to assess for differences and Cox proportional hazards model was used to adjust for covariates. Results: A total of 367 patients met selection criteria were included in the study. Patients receiving TKI were older (≥60 years: 54.7% TKI v 36.4% and RT+TKI 33.3% CRT; P = 0.001), and more patients receiving CRT had uncommon EGFR mutations ( 10.3% CRT v 2.3% RT+TKI and 4.0% TKI; P = 0.020). Other baseline characteristics were well balanced among groups. With a median follow-up of 40.8 months, the median PFS and OS were 16.6 and 55.4 months for the entire cohort. The median PFS and OS for the three subgroups were shown in the table. On multivariable analysis, after adjusting for age, KPS status, smoking status, stage, and type of EGFR mutations, TKI+RT was independently associated with improved PFS (HR, 0.57; 95% CI, 0.41 to 0.78 ) and OS (HR, 0.61; 95% CI, 0.39 to 0.97) relative to upfront TKI; TKI+RT was also associated with improved PFS (HR, 0.38; 95% CI, 0.27 to 0.54 ) relative to CRT, but not OS (HR, 0.66; 95% CI, 0.40 to 1.11). Conclusions: The use of upfront EGFR-TKI with deferred RT at progression was associated with inferior OS in patients with EGFR-mutant unresectable LA-NSCLC. First-line use of radiotherapy and EGFR-TKI was associated with the longest PFS and OS, which requires further prospective, randomized evaluation. [Table: see text]