Effectiveness of Chemoimmunotherapy in Small-cell Lung Cancer Patients With a Poor Performance Status or Higher Neutrophil/Lymphocyte Ratio

Background/Aim: Chemoimmunotherapy has improved overall survival in patients with extensive small-cell lung cancer (SCLC). However, the backgrounds of patients enrolled in clinical trials tend to differ from those of patients treated in clinical practice, and the effectiveness of chemoimmunotherapy may be unclear in some populations, including patients with poor performance status. This study aimed to evaluate the effectiveness of chemoimmunotherapy for SCLC patients in clinical practice while focusing on several subgroups. Patients and Methods: We retrospectively analyzed the data of SCLC patients who received chemoimmunotherapy or chemotherapy. The association between chemoimmuno-therapy and overall survival was evaluated by adjusting for patient backgrounds using the Cox proportional hazards model, followed by a subset analysis. Results: The chemoimmuno-therapy and chemotherapy groups included 43 and 71 patients, respectively. The Cox proportional hazards model showed that chemoimmunotherapy was significantly associated with improved overall survival (hazard ratio=0.47, 95% confidential interval=0.26-0.83). Furthermore, subgroup analysis showed that overall survival was significantly improved in patients with good performance status, lower neutrophil/lymphocyte ratio, and no liver metastases. However, overall survival with chemoimmunotherapy was similar to that with chemotherapy and was less than 12 months in patients with a poor performance status or higher neutrophil/lymphocyte ratio. Conclusion: Chemoimmunotherapy was significantly associated with improved overall survival in clinical practice. However, the effectiveness was equivocal in SCLC patients with a poor performance status or higher neutrophil/lymphocyte ratio.