Statin use is associated with a significant reduction in cancer mortality, conclude two separate studies, one in women, and the other in men. Both were presented here at the American Society of Clinical Oncology (ASCO) 2015 Annual Meeting.
Specifically, statin use was associated with a 22% reduction in deaths from various cancer types in women and a 55% reduction in deaths from bone/connective tissue cancers. The study in men looked at statin use together with the antidiabetes medication metformin and found a 40% reduction in prostate cancer mortality, with the effect more pronounced in men with obesity/metabolic syndrome.
As for how such an effect is achieved, the researchers speculate that statins interfere with cell growth and metastasis by blocking cholesterol production, thereby affecting molecular pathways and the inflammatory 
response.
The results in women were presented by Ange Wang, BSE, from Stanford University School of Medicine, in California.
Dr. Wang and colleagues examined data from the Women’s Health Initiative, a 15-year research program involving postmenopausal women aged 50 to 79 years who were enrolled between 1993 and 1998 at 40 centers in the United States.
They determined the association between patients’ never having used statins, current statin use, and past statin use, as well as the incidence and number of deaths from cancer among 146,326 women. The median follow-up period was 14.6 years.
The researchers took into account a number of potential confounding factors, including age, race/ethnicity, 
education, smoking, body mass index, physical activity, family history of cancer, and current healthcare provider.
Among the participants, there were 23,067 cases of incident cancer for which complete follow-up data were available. There were 7,411 all-cause deaths, including 5,837 deaths from cancer, 613 cardiovascular deaths, and 961 deaths from other causes. In all, 3,152 cancer deaths were included in the analysis, of which 708 were among current statin users and 2443 among patients who had never used statins.
Source: Medscape