The association between 3‐hydroxy‐3‐methylglutaryl conenzyme A inhibitor use and breast carcinoma risk among postmenopausal women

Abstract

BACKGROUNDStatin use has increased dramatically in the U.S. in the past decade. Animal and mechanistic studies suggested that statins may have an inhibitory effect on cancer proliferation, including breast carcinoma. However, statins have been found to be carcinogenic in rodents and one clinical trial found an excess of breast carcinoma cases in the treatment group.METHODSThe current study assessed whether the use of statins altered the risk of breast carcinoma in older women. The population‐based, case–control study comprised female residents from three western Washington State counties. Cases included 975 women identified from the Cancer Surveillance System who were diagnosed with primary invasive breast carcinoma between 1997–1999, whose names appeared on a list of Social Security recipients provided by the Centers for Medicare and Medicaid Services. The cases were ages 65–79 years at the time of diagnosis. The comparison group was comprised of 1007 women without breast carcinoma who were randomly selected from the same list of Social Security recipients. Information pertaining to statin use, medical history, and health behaviors was ascertained through an in‐person interview.RESULTSCompared with nonusers, women who were currently using statins or had ever used statins were not found to be at an increased risk for breast carcinoma (odds ratios [OR] = 0.9; 95% confidence interval [95% CI], 0.7–1.2). There was some indication that long‐term statin use (> 5 years) was related to a slight decrease in breast carcinoma risk (OR = 0.7; 95% CI, 0.4–1.0).CONCLUSIONSThe results of the current study provided some degree of reassurance to the increasing numbers of women using statins that such use is not associated with an increased risk of breast carcinoma. Although the data gave some support to a reduced risk of breast carcinoma among long‐term users of statins, further research is needed to confirm this association. Cancer 2004. © 2004 American Cancer Society.

Post-diagnosis statin use and breast cancer recurrence in a prospective cohort study of early stage breast cancer survivors

“…A large case-control study from the General Practice Research Database, an automated database containing drug prescription and medical information on more than three million people in the United Kingdom, found no association between current statin use and breast cancer risk [10]. Interestingly, another large case-control study with cases from a population-based tumor registry reported no overall association of statins with breast cancer incidence but did find that women who had used statins for more than five years had an approximately 30% lower breast cancer incidence than never users [4]. Two other case-control studies observed no association between statin use and breast cancer risk [6,9].…”

“…For example, laboratory studies have shown that lipophilic statins such as simvastatin and fluvastatin inhibit mammary tumor growth by approximately 50% at doses equivalent to those used in humans for reducing cholesterol [2]. Thus far, observational studies of the association between statins and risk of developing breast cancer have yielded mixed results, with the majority finding no association [3][4][5][6][7][8][9][10]. To our knowledge, no studies have examined statin use and breast cancer prognosis.…”

Estrogen Receptor–Negative Breast Cancer Is Less Likely to Arise among Lipophilic Statin Users

“…The electronic pharmacy database allowed for precise calculation of total exposure to statins; the duration of statin use was accurately reflected in the number of prescriptions dispensed, as few Kaiser patients fill prescriptions outside the Kaiser formulary system. This produces a (17,18,(32)(33)(34)(35). Only two studies have investigated the effect of statins on specific histologic type.…”

Statin Use and Breast Cancer Risk in a Large Population-Based Setting

“…However, one of these large cohort studies by Cauley et al found that statin use was associated with an 18% lower risk of breast cancer when statin use was limited to hydrophobic statin users among women enrolled in the Women's Health Initiative (21). Other observational studies have reported sometimes large reductions in the risk of breast cancer (30-72%) associated with use of statins (16,18,20). Cauley et al also report no association between statin use and breast cancer risk among users of estrogen plus progestin or among never/past hormone therapy user but a nonstatistically significant reduced risk (22%) among users of estrogen alone.…”

“…Epidemiologic studies that report on statin use and breast cancer risk are varied and report no effect on risk and both increases and decreases in risk (13)(14)(15)(16)(17)(18)(19)(20)(21). To assess the association between statin use and breast cancer risk, we conducted a cohort study within a large integrated health care delivery system that contains computerized information on medication use, incident cancers, and risk factors for breast cancer.…”