Adjuvant Chemotherapy for the Completely Resected Stage IB Nonsmall Cell Lung Cancer: A Systematic Review and Meta-Analysis

Adjuvant chemotherapy is recommended for postoperative stage II-IIIB nonsmall cell lung cancer patients. However, its effect remains controversial in stage IB patients. We, therefore, performed a meta-analysis to compare the efficacy of adjuvant chemotherapy versus surgery alone in stage IB patients. Six electronic databases were searched for relevant articles. The primary and secondary outcomes were overall survival (OS) and disease-free survival (DFS). The time-to-event outcomes were compared by hazard ratio using log-rank test. Sixteen eligible trials were identified. A total of 4656 patients were included and divided into 2 groups: 2338 in the chemotherapy group and 2318 in the control group (surgery only). Patients received platinum-based therapy, uracil-tegafur, or a combination of them. Our results demonstrated that patients can benefit from the adjuvant chemotherapy in terms of OS (HR 0.74 95% CI 0.63–0.88) and DFS (HR 0.64 95% CI 0.46–0.89). Patients who received 6-cycle platinum-based therapy (HR 0.45 95% CI 0.29–0.69), uracil-tegafur (HR 0.71 95% CI 0.56–0.90), or a combination of them (HR 0.51 95% CI 0.36–0.74) had better OS, but patients who received 4 or fewer cycles platinum-based therapy (HR 0.97 95% CI 0.85–1.11) did not. Moreover, 6-cycle platinum-based therapy (HR 0.29 95% CI 0.13–0.63) alone or in combination with uracil-tegafur (HR 0.44 95% CI 0.30–0.66) had advantages in DFS. However, 4 or fewer cycles of platinum-based therapy (HR 0.89 95% CI 0.76–1.04) or uracil-tegafur alone (HR 1.19 95% CI 0.79–1.80) were not beneficial. Six-cycle platinum-based chemotherapy can improve OS and DFS in stage IB NSCLC patients. Uracil-tegafur alone or in combination with platinum-based therapy is beneficial to the patients in terms of OS, but uracil-tegafur seems to have no advantage in prolonging DFS, unless it is administered with platinum-based therapy.