Abstract
BACKGROUND: Limited-stage small-cell lung cancer (LS-SCLC) is an aggressive malignancy, and patients with this disease have a poor long-term survival when treated with current standard chemoradiotherapy. Although neoadjuvant or conversion immunotherapy combined with chemotherapy has shown efficacy in patients with non-SCLC (NSCLC), its effect in those with LS-SCLC remains underexplored, particularly regarding long-term survival outcomes. This study aims to evaluate the efficacy and long-term survival of neoadjuvant or conversion immunotherapy plus chemotherapy in patients with LS-SCLC. METHODS: This retrospective study enrolled 34 patients with stage IIB-IIIB SCLC who received neoadjuvant or conversion anti-programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) immunotherapy plus platinum-etoposide chemotherapy, followed by surgical resection. The primary end points were overall survival (OS) and event-free survival (EFS). Pathological complete response (pCR) and major pathological response (MPR) were assessed, and subgroup analyses were performed based on pathological response, demographic factors, and tumor stage. RESULTS: With a median follow-up of 34.2 months, the 2-year EFS and OS rates were 72.1% [95% confidence interval (CI): 53.1-84.5%] and 82.4% (95% CI: 64.9-91.7%), respectively. Among the 34 patients, a pCR rate of 47.1% and an MPR rate of 70.6% were achieved. Patients achieving pCR or MPR had significantly better survival outcomes than did the nonresponders. In the subgroup analysis, a lower body mass index (BMI) (<25.0 kg/m(2)) and earlier disease stage II were associated with improved survival, although this was not statistically significant in all comparisons. CONCLUSIONS: Neoadjuvant or conversion chemoimmunotherapy followed by surgery demonstrates promising efficacy and survival benefits in patients with stage IIB-IIIB SCLC, with high pCR/MPR rates strongly predicting superior outcomes. These findings support the integration of immunotherapy into multimodal treatment strategies for patients with stage II-IIIB SCLC and warrant validation in larger randomized controlled trials.