Cholesterol levels and use of statins are not associated with breast cancer risk

Cholesterol levels and use of statins or other lipid-lowering drugs are not associated with breast cancer risk, according to a study in the October 24 issue of Archives of Internal Medicine.

Although some evidence suggests that statins (the most commonly used type of lipid-lowering drugs) may inhibit tumor development and may work in combination with chemotherapy drugs against cancer, studies on the association between the use of statins and breast cancer have had conflicting results, according to background information in the article.

A. Heather Eliassen, Sc.D., of the Brigham and Women's Hospital, Boston, Mass., and colleagues analyzed data from the Nurses' Health Study to evaluate the associations of statins, lipid-lowering drugs and serum cholesterol levels (blood levels of cholesterol) with breast cancer. Serum cholesterol levels and use of statins and lipid-lowering drugs were determined for 79,994 women through questionnaires completed in 1988, 1994, 1996, 1998 and 2000. Cases of breast cancer, diagnosed from the start of follow-up (1988) through May 31, 2000, were identified on biennial questionnaires. Medical records were used to confirm cancer reports.

There were 3,177 incident cases of invasive breast cancer, including 1,727 in the analysis among statin users. Neither current nor long-term use of statins nor other lipid-lowering drugs were associated with breast cancer risk, the researchers report. There was no association between reported total serum cholesterol levels and breast cancer risk in either pre-menopausal or post-menopausal women.

"In summary, the results of this study suggest that the beneficial effect of statins on breast cancer observed in experimental studies may not be applicable to humans," the authors conclude. "We also found no associations of general lipid-lowering drugs and serum cholesterol levels with breast cancer risk. Further study is warranted to evaluate the associations of longer durations of statin use and specific types of statins with breast cancer risk."