e21606 Background:Breast cancer is the most common cancer in females. The effects of statins on breast cancer prognosis have long been controversial, so it is important to investigate the relationship between statin type, exposure time, and breast cancer prognosis. This study sought to explore the effect of statins on breast cancer prognosis. Methods:We searched the MEDLINE, EMBASE, Cochrane Library between October 15, 2016 and January 20, 2017. Searches combined the terms “breast neoplasms[MeSH]”, “statins”, “prognosis” or “survival” or “mortality” with no limit on publication date. Data were analyzed using Stata/SE 11.0. Results: 7 studies finally met the selection criteria and 197,048 included women. Overall statin use was associated with lower cancer-specific mortality and all-cause mortality (HR 0.73, 95% CI 0.59-0.92, P = 0.000 and HR 0.72, 95% CI 0.58-0.89, P = 0.000). Lipophilic statins were associated with decreased breast cancer-specific and all-cause mortality (HR 0.57, 95% CI 0.46-0.70, P = 0.000 and HR 0.57, 95% CI 0.48-0.69, P = 0.000); however, hydrophilic statins were weakly protective against only all-cause mortality (HR 0.79, 95% CI 0.65-0.97, P = 0.132) and not breast cancer-specific mortality (HR 0.94, 95% CI 0.76-1.17, P = 0.174). Of note, more than four years of follow-up did not show a significant correlation between statin use and cancer-specific mortality or all-cause mortality (HR 0.84, 95% CI 0.71-1.00, P = 0.616 and HR 0.95, 95% CI 0.75-1.19, P = 0.181), while groups with less than four years of follow-up still showed the protective effect of statins against cancer-specific mortality and all-cause mortality (HR 0.62, 95% CI 0.44-0.87, P = 0.000 and HR 0.61, 95% CI 0.45-0.80, P = 0.000). Conclusions:Although statins can reduce breast cancer patient mortality, the benefit appears to be constrained by statin type and follow-up time. Lipophilic statins showed a strong protective function in breast cancer patients, while hydrophilic statins only slightly improved all-cause mortality. Finally, the protective effect of statins could only be observed in groups with less than four years of follow-up.
Expression of CXCR4 and breast cancer prognosis: a systematic review and meta-analysis
