Effects of statin exposure and lung cancer survival: A meta-analysis of observational studies

Statin exposure has been reported to improve survival in several cancers. However, studies evaluating the association between statins and prognostic outcomes in patients with lung cancer are conflicting and heterogeneous. Pubmed, EMBASE and reference lists of included studies were searched to identify studies investigating the association between statin exposure and lung cancer prognosis. The primary outcome measure was overall survival (OS) and secondary ones included cancer-specific survival (CSS) and recurrence-free survival (RFS). Hazard ratios (HRs) with 95% confidence intervals (95% CIs) of these outcomes were pooled using random-effects models. Thirteen studies with data from 99,297 individuals satisfying the inclusion criteria were identified. Studies were ranked to be at low to moderate risk of bias. Meta-analysis showed that statin exposure was significantly associated with improved OS (pooled HR 0.79, 95% CI 0.72-0.86), CSS (pooled HR 0.83, 95% CI 0.77-0.89) and RFS (pooled HR 0.85, 95% CI 0.81-0.89). Subgroup analyses showed that statin users after diagnosis of lung cancer had more survival benefit for OS (HR 0.68, 95% CI 0.51-0.92) than those before diagnosis (HR 0.86, 95% CI 0.81-0.90) and current users (HR 0.79, 95% CI 0.62-1.02) (P for interaction <0.001). Besides, statin users were likely to have more survival benefits in stage IV lung cancer patients (HR 0.77, 95% CI 0.74-0.79) than in mixed stage (I-IV or I-III) patients (P for interaction = 0.004). Statin exposure is associated with significantly improved survival in patients with lung cancer. Future studies are warranted to further demonstrate the therapeutic role of statins in specific lung cancer patients.