ABSTRACT
Background: The benefits of second-line chemotherapy on the overall survival (OS) of small-cell lung cancer (SCLC) patients might be confounded by subsequent therapies. In this study, we aimed to determine the influence of progression-free survival (PFS) and postprogression survival (PPS) on OS after second-line chemotherapy in patients with refractory SCLC treated with amrubicin monotherapy. Materials and Methods: We analyzed the data of 35 patients with refractory SCLC who were treated with amrubicin monotherapy as second-line chemotherapy between July 2005 and December 2015. The correlations of PFS and PPS with OS were statistically analyzed at the individual level using Spearman's rank correlation and linear regression analyses. Results: The correlation between PPS and OS was strong (r = 0.88, P < 0.05, R2 = 0.87), while that between PFS and OS was weak (r = 0.60, P < 0.05, R2 = 0.15). The number of regimens administered after disease progression postsecond-line chemotherapy was significantly associated with PPS (P = 0.003). Conclusions:OS is more strongly linked to PPS than to PFS in refractory SCLC patients who undergo amrubicin monotherapy as a second-line treatment. These results suggest that treatments administered after second-line chemotherapy affect the OS of refractory SCLC patients treated with amrubicin monotherapy