A new research paper published this month in the journal Clinical Cancer Research, tells how scientists have come up with a new method of administering leading breast cancer drug Tamoxifen via a gel, and it appears that while being just as effective as the oral version, it carries fewer side-effects.
The drug Tamoxifen is an anti-estrogen treatment that is used to combat breast cancer and sometimes other cancers. How it works isn’t exactly understood, but what we do know is that some breast cancers need what are known as estrogen receptors to grow. These kinds of cancers are given the name estrogen-receptor positive (ER-positive) breast cancers. By using Tamoxifen, doctors can block the supply of estrogen which in turn can stop or seriously retard the cancers from growing. Tamoxifen has been very successful in this major clinical use but it comes with side-effects, some of which can be very unpleasant and even serious.
Usually, those side-effects are limited to things like nausea, weight gain, and hot flushes or sweating. These are common and not overly problematic as doctors can prescribe things to manage these problems. However, more serious side-effects can include depression, blood clots, vision problems, and migraines. There are also some long terms effects, and one that is often highlighted is very slightly increasing the risk of endometrial cancer, though I hasten to add that while statistically significant the real-world impact of Tamoxifen is only small in that regard.
Yet, all these side-effects can be incredibly unpleasant for cancer sufferers who have already been through rounds of grueling treatment. Some women even decline to take Tamoxifen, which is usually administered orally, because of those side-effects. That could be about to end, though.
The researchers in this latest study trialed the Tamoxifen gel with a small sample of 26 women with what is known as early-stage “ductal carcinoma in situ” (DCIS) cancer, where abnormal cells grow inside the duct tissue. The women, who were all between 45 and 86, had a form of cancer that was estrogen sensitive, meaning that they would have been prescribed Tamoxifen in its oral form. The women were randomly assigned to two different groups: one that would receive Tamoxifen orally, while the other would receive it in gel form. (For exact details on concentrations and more about the delivery method, please click here.)
After a test period of 6-10 weeks where the gel was applied every day directly to the breast, researchers found that signs of cell growth had reduced to the same degree they saw among the group that was taking the oral version of the drug. Crucially though, the women who used the oral drug had 5-times the level of Tamoxifen in their bloodstream and had experienced more side-effects than the gel users.
Seema Khan, lead researcher and oncologist at the Northwestern University Feinberg School of Medicine in Chicago, is quoted as saying that this finding, though obviously on the result of a small human trial, is significant. ”The gel minimized exposure to the rest of the body and concentrated the drug in the breast where it is needed. There was very little drug in the bloodstream, which should avoid potential blood clots as well as an elevated risk of uterine cancer.”
The breast in particular is a good option for this kind of targeted gel treatment because it has its own lymphatic system and therefore doesn’t circulate the drug around the body like many other areas of the body might. That means that while this gel might not be suitable for delivering all medications for cancer treatment, this research does at least suggest that it worth pursuing as an alternative method. Researchers will now have to pursue more widespread clinical trials (we’re currently at phase two of the four-phase process) to confirm these results, but the gel appears promising.
These findings are particularly exciting because Tamoxifen is sometimes used by women who are at high risk of developing breast cancer as a precautionary measure. Obviously, given its side-effects some women may be put off, but the gel form could answer that problem and indeed save lives.
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