Can tamoxifen be taken topically, ie applied to the outside of the breast as a gel and absorbed through the skin, rather than orally, as a tablet?
Tuesday 10 March 2015      Research blog
Bra designed to deliver breast cancer drug - what we think

The Mail Online reported today (10 March 2015) on new technology, built into clothes, which can treat or prevent illness.  One hi-tech item they mentioned caught our eye – “the bra that delivers cancer drugs”.  In this case, researchers and designers have developed a bra that releases tamoxifen to be absorbed through the skin.

There are two things to consider in this story.  Firstly, can tamoxifen be taken topically i.e. applied to the outside of the breast as a gel and absorbed through the skin, rather than orally, as a tablet? And secondly, does the bra deliver tamoxifen in the same way as it would if applying a gel by hand?

Tamoxifen gel

Tamoxifen is usually given to patients as a pill to prevent breast cancer returning after surgery.  This is known as a systemic therapy as the drug travels through the body via the blood steam.  When the drug passes through the liver it’s broken down into smaller molecules that are often responsible for the side effects associated with tamoxifen (hot flushes, nausea, blood clots etc).  Interestingly, tamoxifen can be absorbed through the skin, so a topical version of the drug could be applied directly to the breast and potentially reduce side effects.

What the evidence shows

A tamoxifen gel that can do just this has been under investigation for a few years now but it’s still not clear how it stands up to the pill form of the drug.  A clinical study reported in 2014 trialled a gel versus the pill in 26 patients with very early stage breast cancer, also known as ductal carcinoma in situ (DCIS).  They found that the gel reduced a molecular marker associated with cancer cell division (called Ki67) in a similar way to the pill form of the drug, whilst also reducing side effects.

The authors of the study explained at the time that: "A gel delivered through the breast skin is only for indications where you do not need systemic circulating drug levels, so this would not apply to the great majority of women who are being treated for invasive breast cancer.

“However, for women at high risk for breast cancer or who have been diagnosed with non-invasive breast cancer who need treatment only to the breast, applying a gel to the breast skin would treat the breast but avoid harm to the rest of the body. This might encourage more women to adhere to preventive therapy.”

So it seems that tamoxifen gel could be as good as the pill but only for women with DCIS or when used as a chemopreventative.  It’s important to note that the clinical study mentioned above was done on an extremely small number of women and there still isn’t enough evidence to show the benefit of a tamoxifen gel.

Drug delivering bra

The Foxleaf bra mentioned in the Mail Online article has been developed as a tool to deliver topical tamoxifen to the wearer.  According to the Mail, the bra contains “micro-encapsulated bubbles of the drug tamoxifen in soft, plastic inserts in the cups”.  Heat and moisture is supposed to rub the coating off the bubbles and release the drug onto the skin.

This sounds feasible but a lot of questions need to be addressed first over controlling the dosage of tamoxifen that is released and what level of benefit it brings to women compared to the pill or gel form.  We will need to wait to see the data from the planned clinical studies before we know for sure.

That said, it’s great to see innovative ideas being used to improve healthcare.  Many “high-risk” women who decide to take tamoxifen to prevent breast cancer often struggle to adhere to their treatment.  This type of drug delivery system could help women stick to their treatment, ultimately reducing the number of breast cancer cases.

Dr Matthew Lam is Breakthrough Breast Cancer’s Senior Research Officer

About the author


Dr Matthew Lam is a Senior Research Communications Officer at Breast Cancer Now. He has a PhD in breast cancer research and becomes enraged in the presence of pseudoscience.