Two versus three to four cycles of neoadjuvant immunochemotherapy for stage IB-IIIB non-small cell lung cancer: a real-world study.

Background: No consensus exists regarding the optimal number of cycles of neoadjuvant immunochemotherapy for patients with stage IB-IIIB non-small cell lung cancer (NSCLC). In this study, we compared the efficacy and safety of 2 cycles of neoadjuvant immunochemotherapy in stage IB-IIIB NSCLC with those of 3-4 cycles.

Methods: All patients with IB-IIIB NSCLC who received preoperative immunochemotherapy at the Department of Thoracic Surgery, the First Affiliated Hospital, Zhejiang University School of Medicine, from 2019 to 2022 were consecutively included in this retrospective study. Subsequently, 1:1 propensity score matching (PSM) according to baseline characteristics was performed to compare the efficacy and safety between the 2-cycle group and the 3 to 4-cycle group. The follow-up period was required to be at least 1 year after surgery or when the patient decided to abandon treatment.

Results: Of the 184 patients with stage IB-IIIB NSCLC included in the analysis, 61 received 2 cycles of neoadjuvant immunochemotherapy while 123 received 3-4 cycles. After a 1:1 PSM, there were no significant differences in baseline clinicopathological characteristics among the108 patients (54 pairs) who received 2 cycles or 3-4 cycles of neoadjuvant immunochemotherapy. The objective response rate (ORR) in the 3 to 4-cycle group was significantly higher than that in the 2-cycle group (83.3% 63.0%; P=0.01). The incidence of grade 3-4 adverse events (AEs) in the 3 to 4-cycle group was similar to that of the 2-cycle group (13.0% 9.3%; P=0.54). About 90.7% (49/54) of patients in the 2-cycle group and 46.3% (25/54) in the 3 to 4-cycle group eventually underwent surgery. The rate of major pathological response (MPR) in the 3 to 4-cycle group and 2-cycle group was 68.0% and 69.4% (P=0.90), respectively. The rate of pathological complete response (pCR) in the 3 to 4-cycle group and 2-cycle group was 36.0% and 38.8% (P=0.82), respectively. The median disease-free survival (DFS) in the 3 to 4-cycle group and 2-cycle group was not reached (P=0.80). The 1-year DFS rate and 2-year DFS rate in the 2-cycle group were 87.8% and 77.6%, respectively, while those in the 3 to 4-cycle group were 80.0% and 76.0%, respectively. The median overall survival (OS) in the 2-cycle group was 42.4 months, and it was not reached in the 3 to 4-cycle group (P=0.42). The 1-year OS rate and 2-year OS rate in the 2-cycle group were 93.9% and 87.8%, respectively, while those in the 3 to 4-cycle group were 88.0% and 80.0%, respectively.

Conclusions: Three to four cycles of neoadjuvant immunochemotherapy can result in more tumor regression in IB-IIIB NSCLC. Extending the number of cycles to 3-4 cycles may be feasible and safe in IB-IIIB NSCLC.