Breast Cancer… and Cholesterol?!
Cholesterol, it’s bad for the heart. We know LDL bad, HDL good, eat healthier or ruin your arteries. I’m sure most of us have seen the public service announcements [at least here in the states]. But if that wasn’t a good enough reason for people to watch their cholesterol then how about cancer?An association between high blood cholesterol and breast cancer has been found in a study of more than 1 million patients over a 14 year time period in the UK.
Dr Rahul Potluri, lead author, said: “Our preliminary study suggests that women with high cholesterol in their blood may be at greater risk of getting breast cancer. It raises the possibility of preventing breast cancer with statins, which lower cholesterol, but as this is a primitive study, significant time and research is needed before this idea can be tested.”
The idea from the study came from an interesting association, over the past few years, population studies have suggested an association between obesity and breast cancer. Last year a study in mice concluded that lowering circulating cholesterol or interfering with its metabolism may be used to prevent or treat breast cancer.
“We have a general principle that obesity is linked to breast cancer and a study in mice suggested that this may be because of cholesterol. We decided to investigate whether there was any association between hyperlipidaemia, which is high cholesterol essentially, and breast cancer,” Dr Potluri said.
So the researchers conducted a retrospective analysis of more than 1 million patients across the UK between 2000 and 2013 [using an algorithm for Comorbidities, Associations, Length of stay and Mortality]. 664,159 women were screened using this method and of these, 22 938 had hyperlipidemia [the fancy medical term for high cholesterol] and 9 312 had breast cancer. As it turned out, 530 women with hyperlipidaemia developed breast cancer.
With this information, researchers used a statistical model to study the association between hyperlipidaemia and breast cancer. They found that having hyperlipidaemia increased the risk of breast cancer by 1.64 times [ with a 95% confidence interval 1.50-1.79).
“We found that women with high cholesterol had a significantly greater chance of developing breast cancer. This was an observational study so we can’t conclude that high cholesterol causes breast cancer but the strength of this association warrants further investigation,”says Dr Potluri. “A prospective study that monitors the risk of breast cancer in women with and without high cholesterol is needed to confirm what we observed. If the connection between high cholesterol and breast cancer is validated, the next step would be to see if lowering cholesterol with statins can reduce the risk of developing cancer.”
Statins are cheap, widely available and relatively safe, so researchers are potentially heading towards a clinical trial [unfortunately in 10-15 years] to test the effect of statins on the incidence of breast cancer. If such a trial is successful, statins may have a role in the prevention of breast cancer especially in high risk groups, such as women with high cholesterol.
While the study was preliminary, the results are promising. Researchers found a significant association between having high cholesterol and developing breast cancer, an important association to explore further. Researchers say caution is needed when interpreting the results because while there was a large study population, the analysis was retrospective and observational with inherent limitations.
Potluri, R., Lavu, D., Uppal, H., & Chandran, S. (2014). P740 Hyperlipidaemia as a risk factor for breast cancer? Cardiovascular Research, 103 (suppl 1) DOI: 10.1093/cvr/cvu098.160