Uterine changes during tamoxifen, toremifene, and other therapy for breast cancer. Evaluation with magnetic resonance imaging

We have performed pelvic magnetic resonance imaging (MRI) in patients undergoing breast cancer surgery before and after adjuvant drug therapy. Our purpose was to detect any radiographic uterine changes induced by various types of adjuvant therapy on pre- and postmenopausal patients by evaluating prospectively performed MRI. Between September 2004 and December 2007, a total of 41 women with breast cancer (11 premenopausal, 30 postmenopausal) were enrolled. All underwent MRI of the pelvis before and after drug therapy, and uterine changes were evaluated. Postoperative drugs used were selective estrogen receptor modulators (SERMs) including tamoxifen and toremifene (n=18), aromatase inhibitors (n=13), and anticancer drugs (n=10). Only the postmenopausal patients receiving SERMs showed a significant increase in endometrial thickness: from 2.4±0.4 mm before therapy to 4.5±2.6 mm after therapy (P=0.0485). No statistically significant endometrial change was evident in postmenopausal patients treated with aromatase inhibitors (P=0.573) or anticancer drugs (P=0.754). Also, in premenopausal patients treated with SERMs or anticancer drugs, the change in endometrial thickness was not statistically significant (P=0.958, 0.370). This prospective study using MRI has demonstrated that uterine changes associated with adjuvant drugs for breast cancer occur exclusively in postmenopausal patients receiving SERMs. (author)