Dr. C. Joseph Bennett, Navigating Cancer, 05/07/13

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Low-dose aspirin may halt breast cancer

By Dr. C. Joseph Bennett

Is it possible that the mighty little aspirin could help stop the growth of breast cancer?

Well, if recent animal research is any indication, it may well become part of routine breast cancer treatment.

Research done in test tubes and in mice which was recently presented at a conference in Boston suggests taking low doses of aspirin on a regular basis may stop breast cancer from growing and spreading. However, as I have warned all of my readers before, read these results with an air of caution, this is very early research in animals, and may not translate to the same success in humans.

The research team, from the Veterans Affairs Medical Center in Kansas City and the University of Kansas Medical Center, said tests on cancer cell lines in test tubes and tumors in mice show that aspirin not only significantly slows the growth of cancer cells and shrinks tumors, but also stops tumor cells from spreading to new sites.

Their study investigated the effect of aspirin on two types of cancer, including the so-called aggressive “triple-negative” breast cancer, which does not respond as well to many treatments. Triple-negative breast cancers are so-called because they lack receptors for estrogen, progesterone, and Her2/neu.

Now, the potential for aspirin to be beneficial in cancer patients is not new. Aspirin’s effect on cancer was first suggested 20 years ago, and for more than 20 years, since a study in Australia first suggested aspirin may have anti-cancer properties, researchers have been finding the headache drug may prevent and also treat all sorts of cancer.

For example, there are reports that colon cancer survival improves with aspirin use, and that aspirin and other commonly used painkillers may also help guard against skin cancer. It has also has been shown to reduce the risk of squamous cell esophageal cancer and prostate cancer.

At first it was thought the effect only kicked in after ten years or so, but in 2012, three studies of people in middle age taking low-dose aspirin suggested that the anti-cancer benefits may start after only three years.

However, despite all this evidence, the underlying mechanism through which aspirin confers its anti-cancer benefits have been somewhat difficult to establish. Now this latest study suggests that for breast cancer, it may be that aspirin interferes with the stem cells, immature cells in our body that are believed to fuel the growth and spread of tumors.

For example, if chemotherapy does not destroy stem cells, they will eventually start to grow again. In this new study, researchers found that in the mouse model they used, cancer cells treated with aspirin formed no or only partial stem cells.

In lab tests, aspirin blocked the growth of two different breast cancer lines. One of the cell lines the researchers used was of what is often called triple-negative breast cancer, which is a less common but much more difficult form of breast cancer to treat. The results were promising, but again, I urge all of you to be cautious. This is incredibly early stage research that, as of now, has not been proven in human studies. But it could be promising for the future.

The researchers say aspirin may also improve the effectiveness of current treatments for hormone-receptor-positive breast cancers. In their study, they found aspirin boosted the effect of tamoxifen, which is one of the drugs used used to treat hormone-positive breast cancers.

Many people take a daily low dose of aspirin to lower their risk of a further heart attack or stroke, or if they have a high risk of either. But taking aspirin is not without risks. For instance, daily aspirin use can increase the risk of gastrointestinal bleeding and stomach ulcers. Researchers are continuing to investigate whether the advantages outweigh the potential disadvantages.

So before you rush out and buy a bottle of 360 to begin taking every day, discuss this with your primary care physician or oncologist.

Dr. C. Joseph Bennett is a board-certified radiation oncologist and a member of the Citrus County Unit of the American Cancer Society. Watch “Navigating Cancer” on WYKE TV at 7:30 p.m. Tuesdays and at 10 a.m. Thursdays. If you have any suggestions for topics, or have any questions, contact him at 522 N. Lecanto Highway, Lecanto, FL 34461, or email cjbennett@rboi.com. ­