EGFR-TKI as neoadjuvant treatment in patients with NSCLC with EGFR sensitive mutation: A retrospective real-world analysis.

8081 Background: This study aimed to evaluate the efficacy and outcome of Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) as preoperative neoadjuvant treatment in patients with NSCLC and EGFR sensitive mutation. Methods: A retrospective analysis was conducted. Patients with resectable stage I-III NSCLCs and received neoadjuvant treatment with any generation of EGFR-TKI before surgical resection were enrolled. The primary endpoint were major pathological response (MPR) and objective response rate (ORR), the second endpoints included diseases down staging, surgical outcomes, disease-free survival (DFS) and overall survival (OS). Results: A total of 58 patients were enrolled. Female accounted for 62.1% and most of them (77.6%) were never-smoker. Forty-five (77.6%) patients received the first generation of EGFR-TKI and 11 received the third. The median duration of EGFR-TKI before surgery was 3.6 months (0.7-19.5m). Nine (15.5%) patients achieved MPR and one patient (1.71%) achieved pathological complete response (pCR). The ORR was 60.3% (35/58) according to RECIST v1.1. Eighteen patients achieved TNM downstaging with T downstaging occurred in 44.8% of patients and N downstaging was about 32.8%. Majority of patients (96.6%) underwent thoracoscopic surgery and the rate of R0 resection was 82.8% (48/58). The DFS and OS of the whole cohort was 25.7months and not reached respectively. Patients with MPR had statistically improved outcomes than those without. What noticeable was that patients with tumor regression grade 3 (13/58) (residual viable tumor cells counts for 10% to 50%) also demonstrated a significant benefit from EGFR-TKI preoperative treatment than those with TRG4 or 5 (residual viable tumor cells>50%) (p = 0.01). We define patients with TRG1 to TRG3 as deep pathological regression (DPR) and the rest as non-DPR, and the DPR cohort showed significantly prolonged DFS than those with non-DPR (median DFS, 60.9 vs 16.7 months; HR, 0.29 (95%CI: 0.11-0.74), p = 0.006), the data of OS was not mature. Subgroup analysis validated DPR was an independent predictive factor for DFS. Conclusions: EGFR-TKI as neoadjuvant therapy had good effect on tumor pathological regression and disease downstaging, DPR patients were more likely to achieve long-term disease-free survival. Patients with NDPR should be closely followed up and appropriate adjuvant therapy was necessary after surgery due to the high risk of reccurence.