Abstract CN07-02: Local transdermal therapy for DCIS and for breast cancer prevention

Abstract Pharmacological breast cancer prevention is efficacious but has had low uptake by high risk women. The breast is a skin appendage, with a well-developed internal lymphatic circulation; preliminary studies have shown that small molecules which penetrate the skin concentrate well in the breast with low systemic exposure. We conducted a Phase II randomized trial comparing oral tamoxifen to 4-OHT gel applied to the breast skin, in women needing surgical resection of core-biopsy proven DCIS. Our goal was to assess relative breast tissue drug concentration and anti-proliferative efficacy in DCIS lesions. Although the study was halted early due to interruption in drug supply, preliminary results demonstrate good skin penetration, low systemic concentrations, and reduction in cell proliferation similar to that achieved with oral tamoxifen. These data support the continued investigation of this mode of drug delivery to the breast, with the potential for decreasing the toxicity of proven prevention agents, and for expanding the prevention drug portfolio to effective drugs that penetrate the skin, but systemic use is constrained by toxicity. Citation Format: Seema A. Khan. Local transdermal therapy for DCIS and for breast cancer prevention. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr CN07-02.