Abstract
BACKGROUND: The effect of first-line chemotherapy on overall survival (OS) may be significantly influenced by subsequent therapy for patients with extensive disease small cell lung cancer (ED-SCLC). Therefore, we evaluated the relationship between progression-free survival (PFS), post-progression survival (PPS), and OS of ED-SCLC patients treated with atezolizumab plus carboplatin and etoposide as first-line therapy. METHODS: We analyzed the data of 57 patients with relapsed ED-SCLC treated with atezolizumab plus carboplatin and etoposide (AteCE) as first-line chemotherapy between August 2019 and September 2020. The respective correlations between PFS-OS and PPS-OS following first-line AteCE treatment were examined at the individual patient level. RESULTS: Spearman's rank correlation analysis and linear regression analysis showed that PPS strongly correlated with OS (r = 0.93, p < 0.05, R(2) = 0.85) and that PFS moderately correlated with OS (r = 0.55, p < 0.05, R(2) = 0.28). Performance status at relapse (0-1/≥2), number of cycles of atezolizumab maintenance therapy (<3/≥3), and platinum rechallenge chemotherapy all significantly positively correlated with PPS (p < 0.05). CONCLUSIONS: Upon comparing OS-PFS and OS-PPS in this patient population, OS and PPS were found to have a stronger correlation. These results suggest that performance status at relapse, atezolizumab maintenance, or chemotherapy rechallenge could affect PPS.