Changes in Vascularization of Human Breast Cancer Xenografts Responding to Antiestrogen Therapy

Abstract To elucidate the previously suggested vascular effect(s) of antiestrogen therapy, we studied the effect of estrogen withdrawal and tamoxifen on 1) vascular resistance, 2) glucose and oxygen consumption, 3) vascular density in a perfused breast cancer line (ZR751). Furthermore, we examined ZR75-1 tumors by functional CT-scanning (fCT) to determine changes in parameters related to tumor capillary transfer constants and vascular volume fraction in response to antiestrogenic manipulations. The vascular resistance decreased significantly from 42.7 to 20.8 mmHg × min × g × ml ‡1 ( P P P R = 0.7, P