Continuing Immunotherapy Beyond Progression Prolongs the Survival of Patients With Extensive‐Stage Small‐Cell Lung Cancer: A Multicenter Retrospective Analysis

ABSTRACT Background Platinum‐based two‐agent chemotherapy combined with immunotherapy is now the first‐line standard of care for extensive‐stage small cell lung cancer (ES‐SCLC). Further studies are needed to determine whether continuing immunotherapy (IO) can provide benefit in patients whose disease has progressed after first‐line treatment. Therefore, we conducted a retrospective study to evaluate the efficacy of continuing IO in patients. Methods The study retrospectively collected clinical data of ES‐SCLC patients as progressive disease (PD) after receiving first‐line treatment with PD‐1/PD‐L1 inhibitors. According to whether to continue immunotherapy or not, patients were divided into the continuing IO group and the control group. The differences in progression‐free survival (PFS2, defined as time from progression on first‐line treatment to progression on second‐line treatment) and overall survival (OS) between the two groups were compared. Result As a result, a total of 489 patients from three cancer centers were enrolled in this study, of which 298 patients were included in the continuing IO group and 191 patients were included in the control group. By analysis, it was found that continuing IO could prolong OS (median: 18.82 months vs. 16.43 months, p = 0.008) and PFS2 (median: 4.13 months vs. 3.77 months, p = 0.04) compared to the control group. In subgroup analyses, continuing immunotherapy led to prolonged survival in patients with an initial efficacy evaluation of the complete response (CR) or partial response (PR). And there was also no difference in survival between the PD‐L1 inhibitor group and the PD‐1 inhibitor group in the comparison of different ICIs types. Conclusions Continuation of immunotherapy after standard first‐line immunotherapy plus chemotherapy can improve survival in patients with ES‐SCLC.