Cancer Therapy: Clinical A Randomized Phase II Presurgical Trial of Transdermal 4-Hydroxytamoxifen Gel versus Oral Tamoxifen in Women with Ductal Carcinoma In Situ of the Breast

Purpose: Local transdermal therapy to the breast may achieve effective target-organ drug delivery, while diminishing systemic effects. We conducted a randomized, double-blind, placebo-controlled phase II trial comparing transdermal 4-hydroxytamoxifen gel (4-OHT) to oral tamoxifen (oral-T) in women with ductal carcinoma in situ (DCIS). Methods: Twenty-seven preand postmenopausal women were randomized to 4-OHT (4 mg/day) or oral-T (20mg/day) for 6 to 10 weeks before surgery. Plasma, nipple aspirate fluid, and breast adipose tissue concentrations of tamoxifen and itsmajormetabolites were determined by liquid chromatography/tandem mass spectrometry. The primary endpoint was Ki67 labeling in DCIS lesions, measured by immunohistochemistry. In plasma, insulin-like growth factor-1 (IGFI), sex hormone–binding globulin (SHBG), and coagulation protein concentrations were determined. Results: Posttherapy Ki67 decreased by 3.4% in the 4-OHT and 5.1% in the oral-T group (P 0.03 in both, between-group P 1⁄4 0. 99). Mean plasma 4-OHT was 0.2 and 1.1 ng/mL in 4-OHT and oral groups, respectively (P1⁄4 0.0003), whereasmean breast adipose tissue concentrations of 4-OHTwere 5.8 ng/g in the 4-OHT group and 5.4 ng/g in the oral group (P 1⁄4 0.88). There were significant increases in plasma SHBG, factor VIII, and von Willebrand factor and a significant decrease in plasma IGFI with oral-T, but not with 4-OHT. The incidence of hot flashes was similar in both groups. Conclusions: The antiproliferative effect of 4-OHT gel applied to breast skin was similar to that of oral-T, but effects on endocrine and coagulation parameters were reduced. These findings support the further evaluation of local transdermal therapy for DCIS and breast cancer prevention. Clin Cancer Res; 20(14);