Extended neoadjuvant therapy in NSCLC achieved remarkable pathological complete response (pCR) rate and prolonged disease-free survival.

Abstract

e20500 Background: Over 50% early stage NSCLC patients would suffer from recurrence and distant metastasis. Neoadjuvant TKI therapy had been explored aiming to reduce recurrence and metastasis. Erlotinib neoadjuvant therapy (NAT) significantly improved ORR, PFS and major pathologic response (MPR) rate in trial EMERGING/CTONG1103. In our hospital, some patients received extended neoadjuvant treatment because of continued lesion remission. These patients eventually received surgery when the lesions stopped remission and achieved remarkable pathologically complete remission (pCR) rate. Herein we analyzed the efficacy of extended NAT. Methods: 9 NSCLC patients who received extended neoadjuvant therapy in Department of Thoracic Surgery, Jiangsu Cancer Hospital from 2013-2020 were enrolled in this study. Extended neoadjuvant therapy was defined as duration of treatment longer than standard regimens (for TKI, longer than 42 days; for chemotherapy, longer than 2 cycles or 6 weeks). Pathological complete response, progression free survival (PFS), overall survival (OS) were evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Standard statistical methods, including descriptive statistics, x2 test, two-sided 95% CI were used. Results: Up to 9 patients were enrolled in this study. There were 5 patients in TKI group, 1 (20%) was male and 4 (80%) were female. There were 4 patients in chemo group, 2 (50%) were male and 2 (50%) were female. The median age of TKI and chemotherapy groups were 59 (47-70) and 62 (30-75), respectively. The median duration of treatment (DOT) were 185 (163-248) and 82 (29-98) days, respectively. Among TKI group, 4 patients were EGFR L858R positive and 1 was ALK rearrangement positive and they all received relative TKI treatment based on genetic feature. In the TKI group, all 5 patients achieved pCR, the pCR rate was 100%. In chemotherapy group, 1 out of 4 patients achieved pCR and the other 3 achieved major pathological response (MPR). The pCR rate was 25% and MPR rate was 100%. The pCR rate of TKI group was significantly higher than chemotherapy group (100% vs 25%, p < 0.01). The pCR rate or MPR rate was higher than historical data. For instance, in trial CTONG 1103, neither TKI (Erlotininb) or chemotherapy (Gemcitabine) group achieved pCR, and the MPR rate was only 45% in TKI group and 51% in chemotherapy group. Extended NAT regimen in our study achieved much higher pCR rate (100% vs 0% for TKI and 25% vs 0% for chemotherapy) and MPR rate (100% vs 45%̃51%) than standard 42 days regimens used in CTONG-1103. Conclusions: Extended NAT resulted in better pCR rate and MPR rate than the standard 42-days duration of NAT. For patients with good response to TKI in the neoadjuvant stage, extending the duration neoadjuvant TKI treatment until lesions stopped remission might result in better pCR rate and might extend PFS and OS.