Efficacy of neoadjuvant immunochemotherapy and survival surrogate analysis of neoadjuvant treatment in IB-IIIB lung squamous cell carcinoma.

Until now, there are still few comparisons between neoadjuvant immunochemotherapy and chemotherapy as first-line treatment for patients with stage IB-IIIB lung squamous cell carcinoma (LUSC). In addition, the ability of pathologic response to predict long-term survival has still not been established. In this retrospective, controlled clinical trial, we ultimately enrolled 231 patients with stage IB to IIIB LUSC who received 2-4 cycles perioperative immunochemotherapy or chemotherapy alone, followed by resection. The primary endpoint of this study was pathological response. Secondary endpoints were disease-free survival (DFS), overall survival (OS), objective response rate (ORR), surgical resection rate and adverse events (AEs). The rates of major pathologic response (MPR) and pathologic complete response (pCR) in the immunochemotherapy group were 66.7% and 41.9%, respectively, which were both higher than that in the other group (MPR: 25.0%, pCR: 20.8%) (P < 0.001). The median DFS in the chemotherapy group was 33.1 months (95% CI 8.4 to 57.8) and not reached in the immunochemotherapy group (hazard ratio [HR] for disease progression, disease recurrence, or death, 0.543; 95% CI 0.303 to 0.974; P = 0.038). The median OS of the immunochemotherapy group was not achieved (HR for death, 0.747; 95% CI 0.373 to 1.495; P = 0.41), with the chemotherapy group 64.8 months (95% CI not reached to not reached). The objective response rate (ORR) of immunochemotherapy regimen was higher than that of the chemotherapy regimen (immunochemotherapy: 74.5%, chemotherapy: 42.3%, P < 0.001). About 60.8% in the immunochemotherapy group and 61.5% in the chemotherapy group eventually underwent surgery. The incidence of grade3 and 4 adverse events was 18.3% in the immunochemotherapy group and 2.6% in the chemotherapy group. MPR was significantly associated with DFS and OS (HR, 0.325; 95% CI 0.127 to 0.833; P = 0.019; and HR, 0. 906; 95% CI 0.092 to 1.008; P = 0.051, respectively). The C-index of MPR (0.730 for DFS, 0.722 for OS) was higher than the C-index of cPR (0.672 for DFS, 0.659 for OS) and clinical response (0.426 for DFS, 0.542 for OS). Therapeutic regimen (P < 0.001; OR = 7.406; 95% CI 3.054 to 17.960) was significantly correlated with MPR. In patients with stage IB to IIIB LUSC, neoadjuvant treatment with immunochemotherapy can produce a higher percentage of patients with a MPR and longer survival than chemotherapy alone. MPR may serve as a surrogate endpoint of survival to evaluate neoadjuvant therapy.