Relationship of breast magnetic resonance imaging to outcome after breast-conservation treatment with radiation for women with early-stage invasive breast carcinoma or ductal carcinoma in situ.

PURPOSE To determine the relationship of breast magnetic resonance imaging (MRI) to outcome after breast-conservation treatment (BCT) with radiation for women with early-stage invasive breast carcinoma or ductal carcinoma in situ. PATIENTS AND METHODS A total of 756 women with early stage invasive breast carcinoma or ductal carcinoma in situ underwent BCT including definitive breast irradiation during 1992 to 2001. At the time of initial diagnosis and evaluation, routine breast imaging included conventional mammography. Of the 756 women, 215 women (28%) had also undergone a breast MRI study, and 541 women (72%) had not undergone a breast MRI study. The median follow-up after treatment was 4.6 years (range, 0.1 to 13.5 years). RESULTS For the women with a breast MRI study compared with the women without a breast MRI study, there were no differences in the 8-year rates of any local failure (3% v 4%, respectively; P = .51) or local-only first failure (3% v 4%, respectively; P = .32). There were also no differences between the two groups for the 8-year rates of overall survival (86% v 87%, respectively; P = .51), cause-specific survival (94% v 95%, respectively; P = .63), freedom from distant metastases (89% v 92%, respectively; P = .16), or contralateral breast cancer (6% v 6%, respectively; P = .39). CONCLUSION The use of a breast MRI study at the time of initial diagnosis and evaluation was not associated with an improvement in outcome after BCT with radiation.