Statins & Risk of Site-specific Cancers
Our primary aims were:
1. To evaluate the association between statin use and breast cancer risk among women age 45 years and older.
2. To evaluate the association between statin use and prostate cancer risk among men age 45 years and older.
Our secondary aims were:
1. To assess the effect that cumulative duration of exposure to statins has on the risk of breast and prostate cancers.
2. To assess if the risk of breast and prostate cancer differ by type of statin.
3. To evaluate the association between statin use and stage at diagnosis for breast and prostate cancers. (We were unable to this aim because the majority of breast and prostate cancers were stage I or stage II. Instead, we evaluated aggressive prostate cancer risk by statin use and the association between statin use and breast density.)
4. To evaluate the association between statin use and histology of breast cancer
5. To evaluate the association between statin use and female reproductive/genital organ cancers (uterine, ovarian, and vaginal) among women age 45 years and older.
We conducted a retrospective cohort study from 1990 through 2003 within Group Health Cooperative (GHC). Cancer cases were identified through the western Washington Surveillance, Epidemiology, and End Results registry. Information on statin use and covariates was obtained from automated administrative data files, which include pharmacy records, laboratory values, hospitalizations, outpatient visits, and cause of death. Automated data from GHC’s Breast Cancer Surveillance Program will be used to identify other covariates for the women under study such as reproductive history, menopausal status, family history of cancer, body mass index, and frequency of mammography screening for the female cohort.
The prevalence of statin use continues to rise among older adults and the rates of incident breast and prostate cancers are increasing among this same population. Exploring the association between statin use and these two cancers is an important part of the effort to understand the etiology of cancer, address drug safety questions, and a possible opportunity for prevention. Results of this grant have contributed to the literature in this area and our useful in disentangling the complicated relation between statins and cancer, as well as reassuring the public on the safety of statins as they relate to cancer.