Background: The aim of this study was to perform a systematic review and meta-analysis of all randomized controlled trials that compared the efficacy of doublet versus single third-generation cytotoxic agent as first-line treatment for elderly patients with advanced non-small-cell lung cancer (NSCLC).
Methods: Several databases including PubMed, Embase, and Cochrane databases were searched. The endpoints were overall survival (OS), time to progression (TTP), 1-year survival rate (1-year SR), overall response rate (ORR), and grade 3 or 4 adverse event (AE). We performed a meta-analysis of the randomized controlled trials using a fixed-effects model and an additional random-effects model when applicable. The results of the meta-analysis were expressed as hazard ratio (HR) or risk ratio (RR), with their corresponding 95 % confidence intervals (95 % CI). A subgroup meta-analysis was performed based on chemotherapy regimens.
Results: Ten eligible trials involving 2,510 patients were identified. The intention-to-treatment (ITT) analysis demonstrated that doublet therapy was superior to single agent in terms of OS (HR = 0.84, 95 % CI = 0.71-1.00, p = 0.053), TTP (HR = 0.76, 95 % CI = 0.60-0.96, p = 0.022), 1-year SR (RR = 1.17, 95 % CI = 1.02-1.35, p = 0.03), and ORR (RR = 1.54, 95 % CI = 1.36-1.73, p = 0.000). Subgroup analysis also favored platinum-based doublet therapy in terms of 1-year SR (RR = 1.40, 95 % CI = 1.09-1.81, p = 0.009) and ORR (RR = 1.64, 95 % CI = 1.38-1.96, p = 0.000). Though gemcitabine-based doublet significantly increased ORR compared with single agent (RR = 1.45, 95 % CI = 1.23-1.71, p = 0.000), it did not translate into an increase in survival benefits. In addition, more incidences of grade 3 or 4 anemia, thrombocytopenia, and neurotoxicity were observed in the doublet combination group. With respect to grade 3 or 4 neutropenia and nonhematologic toxicities such as diarrhea, fatigue, nausea, and vomiting, equivalent frequencies were found between the two groups.
Conclusions: Our results indicated that doublet therapy was superior to a single third-generation cytotoxic agent for elderly patients with advanced NSCLC. The optimal dosage and schedule of platinum-based doublet should be investigated in future prospective clinical trials. Gemcitabine-based doublet could be considered for elderly patients who were not suitable for platinum-based chemotherapy.