Efficacy of different monotherapies in second-line treatment for small cell lung cancer: a meta-analysis of randomized controlled trials

Second-line chemotherapy has been proved to be effective on patients with relapsed or refractory small cell lung cancer (SCLC). Although topotecan has been approved by many countries for the monotherapy with an acknowledged efficacy, its efficacy of low response rate and short median survival time is disappointing. Considering the optimal regimen of second-line therapy is yet uncertain, we conducted this meta-analysis to provide theoretical basis for making clinical decisions. A comprehensive electronic search was performed to identify eligible studies. The ending points included response, overall survival (OS), and adverse events. Odds ratios and 95% confidence interval were calculated to compare the effects. Six trials with 1369 patients were included. With regard to response rate, only amrubicin showed a significant improvement compared with topotecan. Irinotecan and etoposide did not show any advantages. When targeted on OS, neither of these monotherapy regimens exhibited any advantage when compared to topotecan. When aimed at toxicity, amrubicin showed a better effect on reducing hematologic toxicity, but a worse outcome on increasing the nonhematologic toxicity, whereas others showed equal efficacy. There is no strong evidence that any advantage for second-line treatment of SCLC when compared with topotecan, except amrubicin. And amrubicin seems to be superior to topotecan in terms of response rates, with a lower toxicity than topotecan, which is of high value in clinical application, and may be the direction of second-line monotherapy in the future.