Neoadjuvant Percutaneous 4-Hydroxytamoxifen Decreases Breast Tumoral Cell Proliferation: A Prospective Controlled Randomized Study Comparing Three Doses of 4-Hydroxytamoxifen Gel to Oral Tamoxifen

Purpose Two chemoprevention randomized studies using tamoxifen showed drug efficacy; however, adverse effects such as hot flushes, endometrial cancer, and above all, thromboembolism, remain a problem. 4 hydroxytamoxifen (4-OHT) is a very active metabolite of tamoxifen. This randomized study was designed to analyze if 4-OHT gel, administered percutaneously on the breast skin, can inhibit the proliferation of malignant breast cells to the same extent as orally administered tamoxifen. Patients and Methods Fifty-five postmenopausal women with an invasive estrogen receptor–positive breast cancer were randomly assigned to receive (for 2 to 3 weeks) either 4-OHT gel (0.5, 1, or 2 mg/d) or oral tamoxifen (20 mg/d) or no treatment. Response was evaluated using proliferation markers (Ki-67, proliferating cell nuclear antigen) and apoptosis markers in tissue samples obtained by Tru-cut biopsy before treatment, and at surgery after treatment. Results Administration of 4-OHT gel resulted in reductions in tumor tissue ...