Cancer Research Lab

Statin use is not associated with an increased or decreased risk of breast cancer, according to a population-based, case-control study published in the January 1st issue of Cancer.

“Findings that statins inhibited the proliferation of breast cancer cells in vitro and in rodents have raised interest in whether the use of statins might decrease a woman’s risk of developing breast cancer,” Dr. Gaia Pocobelli, of the University of Washington, Seattle, and colleagues write. Conversely, other studies in which rodents were exposed to high doses of statins showed increases in several types of cancer.

The researchers identified 4179 cases of incident invasive breast cancer in women at least 50 years of age who were diagnosed between January 1995 and May 2001. The women were randomly selected from population-based cancer registries in Wisconsin, Massachusetts, and New Hampshire.

A total of 4983 controls were also randomly selected in each state, from lists of licensed drivers and Medicare beneficiaries. Structured telephone interviews were conducted to obtain information on the use of statins and breast cancer risk factors.

Overall, 7.0% of all the women ever used a statin, including 271 cases and 336 controls. The most commonly used statins included lovastatin (2.8%) and simvastatin (2.4%). This was followed by pravastatin (1.6%) and fluvastatin (1.0%).

Cases had a slightly greater mean cumulative duration of statin use than controls (4.9 years and 4.5 years, respectively), but the overall use of statins was not associated with breast cancer risk, according to the authors. They also observed no relationship between duration of use and cancer risk.

No association was observed between the use of lipophilic statins as a group (simvastatin, lovastatin, fluvastatin) or the use of the hydrophilic statin (pravastatin) and breast cancer risk.

Fluvastatin was associated with a small reduced risk of breast cancer, but this relationship may have emerged by chance, the researchers note.

Summing up, statin usage, either lipophilic or hydrophilic, was unrelated to the risk of breast cancer in middle-age women, the researchers conclude. However, given the extensive use of these agents, they suggest that further investigation of individual statins is warranted.