A new prospective study has reported that Danish breast cancer survivors using the lipophilic statin Zocor have approximately 10% fewer recurrences over the first ten years after diagnosis than those who do not use a statin. There is increasing evidence that statins influence diseases other than cardiovascular disease, including cancer, and that these effects may be dependent on the lipid solubility of specific statins. Depending on the compound, statins are classified either as lipophilic (e.g., Lipitor, Zocor, Mevacor, Lescol) or hydrophilic (Crestor, Pravachol). Though many studies have reported an association between statin use and risk of breast cancer, there is little data concerning the relationship between statin use and breast cancer recurrence.

The study included all 18,769 Danish women diagnosed with stage I-III invasive breast cancer between 1996 and 2003 in the Danish Breast Cancer Cooperative Group registry. The women were followed for a median of 6.8 years after diagnosis. The national electronic pharmacy database was used to find statin and other prescriptions for the women. Associations between statin prescriptions and breast cancer recurrence were calculated while adjusting for age at diagnosis, menopausal status, histological tumor grade, estrogen receptor (ER) status, receipt of adjuvant treatment, type of primary breast surgery, pre-diagnosis hormone replacement therapy (HRT), and concurrent prescriptions of aspirin, angiotensin-converting enzyme inhibitors (ACE inhibitors), nonsteroidal anti-inflammatory drugs (NSAIDs), or anticoagulants.

Most of the prescriptions for lipophilic statins among the women were for Zocor (simvastatin). Exclusive Zocor users experienced approximately 10 fewer breast cancer recurrences per 100 women after 10 years of follow up compared with women who did not use a statin. On the other hand, exclusive hydrophilic statin users were found to have approximately the same risk of breast cancer recurrence as women not prescribed a statin. The authors conclude that Zocor, a highly lipophilic statin, was associated with reduced risk of breast cancer recurrence among Danish women diagnosed with stage I-III breast carcinoma, whereas no association between hydrophilic statin use and recurrence was found.