Effects of statins on cancer mortality and progression: A systematic review and meta-analysis of 95 cohorts including 1,111,407 individuals

Statins have been implicated in the regulation of cell proliferation, apoptosis and tumor progression in cancer patients and statin use at the time of cancer diagnosis has been reported to be associated with reduced cancer risk and improved survival, irrespective of concomitant anti-cancer therapy. A systematic literature search of relevant databases through May 2015 was conducted to identify studies assessing the prognostic impact of statin use on prognostic outcomes in cancer patients. Literature search identified 95 cohort studies that met the inclusion criteria. A meta-analysis of 55 articles showed that statin use was significantly associated with decreased risk of all-cause mortality (HR 0.70, 95% Cl 0.66 to 0.74) compared with nonusers. The observed pooled estimates were retained for cancer-specific mortality (HR 0.60, 95% Cl 0.47 to 0.77), progressionfree survival (HR 0.67, 95% Cl 0.56 to 0.81), recurrence-free survial (HR 0.74, 95% Cl 0.65 to 0.83) and disease-free survival (HR 0.53, 95% Cl 0.40 to 0.72). These associations almost remained consistent across those outcomes when stratified by publication type, tumour location, study design, sample size, initiation of statins, disease stage, research country, follow-up duration or research hospital involved. Subgroup analyses according to initiation of statins showed postdiagnosis statin users (HR 0.65, 95% Cl 0.54 to 0.79) gained significantly more recurrence-free survival benefit than prediagnosis statin users (HR 0.86, 95% Cl 0.77 to 0.96) (p for interaction = 0.018). Statin therapy has potential survival benefit for patients with malignancy. Further large-scale prospective studies emphasising survival outcomes of individual cancer type are strongly encouraged.