85P - The impact of adjuvant EGFR-TKIs and 14-gene molecular assay on patients with stage I non-small cell lung cancer harboring sensitive EGFR mutations

Background

Currently, the role of EGFR-TKIs as adjuvant therapy for stage I, especially IA NSCLC, after surgical resection remains unclear. We aimed to compare the effect of EGFR-TKIs versus observation on survival in such patients by incorporating an established 14-gene molecular assay for risk stratification.

Methods

From March 2013 to February 2019, completely resected stage I (8^th TNM staging for NSCLC) non-squamous NSCLC patients with sensitive EGFR mutation, who were followed up for at least five years, were included. Patients with eligible samples for molecular risk stratification were subjected to the 14-gene prognostic assay. The 5-year disease-free survival (DFS) rates between patients who underwent EGFR-TKI treatment and observation were compared using Kaplan-Meier analysis and Cox regression with a propensity score matching (PSM). The results of the 14-gene assay were used to further stratify the effect of EGFR-TKIs in different risk groups.

Results

A total of 227 stage I NSCLC patients were enrolled, with 110 in stage IA and 117 in stage IB. After PSM, a matched cohort with 96 (48:48) patients was generated. The median duration of follow-up was 78.9 months. In the overall population, patients with adjuvant EGFR-TKIs had better 5-year DFS rates than those in the observation group (97.9% vs. 81.3%; P = 0.008). For patients with IA NSCLC, those receiving EGFR-TKIs had favorable 5-year DFS rates (100.0% vs. 88.2%; P = 0.485); a same trend was obtained from IB group (96.8% vs. 77.4%; P = 0.053). The 14-gene assay was performed in 71 patients. In the observation group, patients in high-risk group had inferior DFS compared with those with intermediate (HR = 3.48, P = 0.192) and low-risk group (HR = 12.50, P = 0.024). Among intermediate-high-risk patients, EGFR-TKIs were associated with a significant trend in 5-year DFS rate benefit compared to observation (95.2% vs. 68.8%; P = 0.066), while there was no difference among low-risk group (100.0% vs. 89.5%; P = 0.492).

Conclusions

We showed that adjuvant EGFR-TKI might improve DFS of EGFR-mutated stage IA and IB NSCLC, and the 14-gene molecular assay could help enrich those benefits from treatment. This modality merits prospective interventional trials in the future.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.