Background: This study aims to investigate the association between statin use and all-cancer survival in a prospective cohort of postmenopausal women, using data from the Women's Health Initiative Observational Study (WHI-OS) and Clinical Trial (WHI-CT). Methods: The WHI study enrolled women aged 50–79 years from 1993 to 1998 at 40 US clinical centres. Among 146 326 participants with median 14.6 follow-up years, 23 067 incident cancers and 3152 cancer deaths were observed. Multivariable-adjusted Cox proportional hazards models were used to investigate the relationship between statin use and cancer survival. Results: Compared with never-users, current statin use was associated with significantly lower risk of cancer death (hazard ratio (HR), 0.78; 95% confidence interval (CI), 0.71–0.86, P<0.001) and all-cause mortality (HR, 0.80; 95% CI, 0.74–0.88). Use of other lipid-lowering medications was also associated with increased cancer survival (P-interaction (int)=0.57). The lower risk of cancer death was not dependent on statin potency (P-int=0.22), lipophilicity/hydrophilicity (P-int=0.43), type (P-int=0.34) or duration (P-int=0.33). However, past statin users were not at lower risk of cancer death compared with never-users (HR, 1.06; 95% CI, 0.85–1.33); in addition, statin use was not associated with a reduction of overall cancer incidence despite its effect on survival (HR, 0.96; 95% CI, 0.92–1.001). Conclusions: In a cohort of postmenopausal women, regular use of statins or other lipid-lowering medications was associated with decreased cancer death, regardless of the type, duration, or potency of statin medications used
