Abstract OT2-02-01: Brazilian randomized study - Impact of preoperative magnetic resonance in the evaluation for breast cancer conservative surgery (BREAST-MRI trial)

Background: A precise preoperative evaluation of the tumor is essential to improve breast cancer surgical management. Currently, mammography associated with ultrasound and clinical exam are the standard techniques for evaluating extension and tumor localization. However, approximately one third of the lesions in patients eligible for conservative surgical treatment are misevaluated by these methods. Breast magnetic resonance imaging (MRI) has a high sensitivity (95-100%) in detecting invasive neoplasms, and is able to detect occult tumors, multifocal and/or multicentric disease, and contralateral breast cancer more accurately than mammography and ultrasound. Until now, there are only three randomized trials assessing the role of preoperative MRI. These trials have different designs and contradictory results. Trial design: BREAST-MRI is a randomized, open label, unblinded trial designed to compare the accuracy of breast MRI in the preoperative planning of surgical treatment of breast cancer to standard protocol (clinical exam of the breast, mammography and/or breast ultrasound) and the impact of breast MRI on breast cancer outcome. Patients are randomized on a 1:1 basis, stratified for mammary density, into two groups: 1)MRI group: patients are submitted to MRI and standard protocol 2)Control group: standard protocol. First phase: patient recruitment and data collection up until surgery. Second phase: follow-up for five years or until death. Eligibility criteria: women aged 18 years or older with breast cancer stages I to III candidates for conservative surgery (CC). Specific aims: The aim of this study is to evaluate the ability of MRI in selecting patients for conservative treatment of breast cancer. Primary outcomes are: false positive rates, false negative rates, positive predictive value and negative predictive value of MRI in breast cancer CC. Secondary outcomes are: rates of positive margins on pathological examination; reoperation rates; number of conversions to mastectomy; accuracy of MRI according to mammographic density, immunohistochemical subtype and histopathology of the tumor; rates of multicentricity, multifocality and bilateralality of tumors; disease-free survival after 3 and 5 years; and cost-effectiveness of breast MRI. Statistical methods: The calculated total case number for this trial is 372, assuming a recurrence rate of 10% for CC and 1% for mastectomies. The Shapiro-Whilks test will be used to verify if distribution of the quantitative variables follows normal distribution. The baseline population will be analyzed using the t-Student test, or the Mann-Whitney test when appropriate. To test the existence of a possible association between outcomes and the categorized characteristics, chi-square and Fisher9s exact test will be performed. Disease progression will be reassessed at 3 and 5 years follow-up, in order to produce a log-rank Kaplan-Meier curve of survival. Present accrual and target accrual: In June 2017, randomizations are at approximately 90% of the target sample size. Citation Format: Doria MT, Mota BS, Reis YN, Ricci MD, Piato JRM, Ferreira VCCS, Shimizu C, Barros N, Filassi JR, Baracat EC. Brazilian randomized study - Impact of preoperative magnetic resonance in the evaluation for breast cancer conservative surgery (BREAST-MRI trial) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-02-01.