Transcript: Statin Cholesterol Drugs and Invasive Breast Cancer
What does breast cancer do with cholesterol? Here are some of the potential mechanisms by which cholesterol boosts breast cancer growth. Cholesterol is what our body makes estrogen out of, it’s packaged into LDL, which we saw appeared to increase proliferation of breast cancer cells, decrease patient survival, and it’s a major component of lipid rafts.
Compared with their normal counterparts, cancer cells have higher levels of cholesterol-rich lipid rafts in their plasma membrane, which may be important for cancer cell survival, as well as serve in human cancer development in terms of tumor migration and invasion.
Elevated levels of cholesterol-rich lipid rafts have been found in breast cancer cells, and the thought is that reducing blood cholesterol levels may disrupt lipid raft formation and thereby inhibit breast cancer development. This suggests cholesterol targeting may be used as a cancer therapy.
Controlled laboratory experiments have shown that phytosterols in seeds and nuts at dietary relevant levels appear to inhibit the growth of several types of tumor cells including breast cancer cells, both estrogen-receptor negative and estrogen-receptor positive cancer.
The therapeutic implications are that plant-based diets rich in phytosterols may offer protection against the development of breast cancer. Of course you can’t make a lot of money on pumpkin seeds, so researchers looked to cholesterol-lowering statin drugs.
However, evaluating the safety of statin therapy for women is particularly difficult. Little research has explicitly proceeded from a gender-based perspective. Some petri dish work looked promising, but population studies have shown mixed results. Some studies showed that women on statins had decreased breast cancer risk, some showed increased risk, and most showed no association. But these were all relatively short-term studies. So-called “long-term” statin use was defined as mostly just three to five years. Breast cancer can take decades to grow. The one study that looked at ten or more years of statin use only included 62 cases. Given the increase in statin use over the past few decades, and the fact that they’re commonly prescribed to be taken every day for the rest of people’s lives, the studies published to date have had limited ability to evaluate the impact of long durations of use. And we better figure this out. About one in four women over 45 in this country are on these drugs. But that was the only data we had, until now.
Thousands of breast cancer cases included, and long term statin users—women taking statins for ten years or more, had more than double the risk of both types of breast cancer: invasive ductal carcinoma and invasive lobular carcinoma.
Now, the number one killer of women is heart disease, not breast cancer, so we still need to bring down cholesterol levels. But might there be a way to get the benefits without the risks. Plant-based diets have been shown to lower LDL-cholesterol by over 30%, within just a couple weeks, equivalent to most of the standard cholesterol lowering statin drugs without potential side effects such as increased breast cancer risk.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.
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