Tamoxifen in gel form is effective with less side effects

Seema Khan, MD, professor of surgery, found a new skin gel that reduced the growth of cancer cells minimizing dangerous side effects. A gel form of tamoxifen applied to the breasts of women with noninvasive breast cancer reduced the growth of cancer cells to the same degree as the drug taken in oral form but with fewer side effects that deter some women from taking it, according to new Northwestern Medicine research.

Tamoxifen is an oral drug that is used for breast cancer prevention and as therapy for non-invasive breast cancer and invasive cancer. Because the drug was absorbed through the skin directly into breast tissue, blood levels of the drug were much lower, thus, potentially minimizing dangerous side effects — blood clots and uterine cancer.

The gel was tested on women diagnosed with the non-invasive cancer ductal carcinoma in situ (DCIS) in which abnormal cells multiply and form a growth in a milk duct. Because of potential side effects, many women with DCIS are reluctant to take oral tamoxifen after being treated with breast-saving surgery and radiation even though the drug effectively prevents DCIS recurrence and reduces risk of future new breast cancer.

The paper was published in Clinical Cancer Research on July 15.

“Delivering the drug though a gel, if proven effective in larger trials, could potentially replace oral tamoxifen for breast cancer prevention and DCIS and encourage many more women to take it,” said lead author Seema Khan, MD, a Northwestern Medicine surgical oncologist. “For breast cancer prevention and DCIS therapy, effective drug concentrations are required in the breast. For these women, high circulating drug levels only cause collateral damage.”

Khan is a professor of surgery and the Bluhm Family Professor of Cancer Research at Northwestern University Feinberg School of Medicine. She also is a surgeon at Northwestern Memorial Hospital and co-leader of the breast cancer program at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University