Real-world data after introduction of chemoimmunotherapy in patients with extensive-disease small cell lung cancer: A multicenter retrospective study

BACKGROUND: First-line combination therapy with anti-programmed cell death ligand 1 antibodies and platinum-based chemotherapy (chemoimmunotherapy) for extensive-disease small cell lung cancer (ED-SCLC) has been shown to be effective in clinical trials and widely used. Since the introduction of chemoimmunotherapy, very few studies have evaluated the treatment details and outcomes for patients with ED-SCLC in clinical settings. METHODS: We enrolled 181 ED-SCLC patients who received first-line chemotherapy or chemoimmunotherapy at 11 institutions in Japan between August 2019 and June 2023. We retrospectively investigated the characteristics and treatment regimens of patients with ED-SCLC who received first-line treatment. RESULTS: Ninety-six (53.0 %) and 85 (47.0 %) ED-SCLC patients received chemoimmunotherapy and chemotherapy, respectively. The proportions of older patients (≥75 years) and those with interstitial pneumonia were significantly higher in the chemotherapy group than in the chemoimmunotherapy group (age: 56.5 % vs. 28.1 %, p < 0.001; interstitial pneumonia: 41.2 % vs. 9.4 %, p < 0.001, respectively). The median overall survival in chemoimmunotherapy and chemotherapy groups were 15.0 and 9.7 months, respectively. The most common reasons for not selecting chemoimmunotherapy were interstitial pneumonia (34 patients,18.8 %), older age (27 patients, 14.9 %), and poor performance status (24 patients, 13.3 %). CONCLUSION: Although the efficacy of chemoimmunotherapy for patients with ED-SCLC has been suggested, only about half of the patients with ED-SCLC select chemoimmunotherapy, and there are various challenges in the treatment of ED-SCLC in clinical settings.