Abstract P4-02-12: Breast MRI: Enhancing pre-operative planning in women with newly diagnosed breast cancer

Abstract Hypothesis: Preoperative breast MRIs in newly diagnosed breast cancer patients may lead to additional findings, including larger disease involvement, thus leading to a change in the operative plan. This information can led to better surgical planning and decreased rates of surgical re-excisions. Methods: This was a single surgeon, single institution, retrospective analysis of women with newly-diagnosed breast cancer who had surgery between December 2013 and December 2014. A total of ninety-six patients underwent preoperative breast MRI. Exclusion criteria were patient's refusal of MRI or surgery, contraindication to MRI based on implants or body habitus, and male patients. Results: Overall, breast MRI most closely correlated to pathological tumor size (gold standard). MRI had a 64% correlation with pathology size, whereas mammography and ultrasound correlation were 44% and 43% respectively. As breast density increased, MRI correlation to pathologic tumor size improved. For breast density between 25-50%, tumor size by MRI correlated with pathology size in 27% of patients, mammogram correlation was 33% and ultrasound was 12%. When breast density increased to 51-75%, MRI correlation improved to 92%, whereas mammogram correlation was 56% and ultrasound was 68%. The majority of patients fell within these two density categories; correlation for breast density <25% and >75% were not statistically significant. Of the breast biopsies preformed for MRI abnormalities not otherwise identified by mammography or ultrasound, 42% were positive for invasive cancer or DCIS. Thirty-eight percent of patients had a change in operative plan based on their MRI findings. Of the ninety-six patients, nine were changed from breast conserving surgery to mastectomy, and 29 underwent a larger area of resection than planned prior to MRI, due to findings of more extensive disease on MRI not otherwise appreciated by mammography or ultrasound. Conclusion: Pre-operative MRI played a significant role in the pre-surgical evaluation of patients with newly diagnosed breast cancer. In our series, breast MRI demonstrated better correlation with extent of disease compared to other imaging modalities. This is turn enhanced patient and surgeon decision making and led to more precise pre-operative surgical planning. Citation Format: Carr B, Lamb LC, Zarfos K, Weigert J, Singh R. Breast MRI: Enhancing pre-operative planning in women with newly diagnosed breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-02-12.