No link found between statins and breast cancer

May 17 2006

According to a new study by U.S. researchers, women who use statin drugs to lower their cholesterol are no more likely to develop breast cancer than women who do not use the drugs.

The study is apparently the largest yet to evaluate statin use and invasive breast cancer in terms of the number of incidents of breast cancers, and directly contradicts some earlier studies that suggested such a link.

Previous studies on statin use and breast cancer risk have provided mixed results.

In the current study, statin users had a somewhat lower breast cancer incidence than nonusers, but the differences were statistically significant only in women who reported using hydrophobic statins.

This may explain the inconsistency in previous results and may reflect differences in the association with specific statins.

The study involved as many as 156,361 women, and when virtually every other risk factor was considered such as a family history of breast cancer, alcohol consumption, physical activity, mammography utilization, menopausal hormone therapy, smoking, etc. no association was found between between statin use and breast cancer.

But it found there was a possibility that certain formulations of statin drugs may reduce breast cancer risk.

Statins are some of the most widely prescribed drugs in the United States, and the researchers say that because breast cancer is the most frequent cancer in U.S. women, any link between statin use and breast cancer risk would have major public health implications.

The researchers, from universities across the United States, studied the medical records of more that 156,000 women past menopause taking part in the Women's Health Initiative study.

In that study it was found that 7.5 percent of the women used statins.

Over the six-plus years of the study, about 4,300 women were diagnosed with breast cancer and according to study leader Dr. Jane Cauley of the University of Pittsburgh.

There was not a significant difference among the women who took statins and those who did not.

However women who used a certain type of statin, known as hydrophobic statins, had an 18 percent lower risk of breast cancer.

The researchers conclude that when all statins are considered together as a class, no statistically significant association with breast cancer was seen.

However, use of hydrophobic statins was associated with statistically significantly lower breast cancer incidence, a finding they believe warrants further evaluation.

The study is published in the Journal of the National Cancer Institute.