A Retrospective Study Evaluating the Impact of Preoperative Breast MRI on Surgical Decision-Making in Young Patients (≤50 Years) with Invasive Breast Cancer

Introduction: Breast magnetic resonance imaging (MRI) is considered a more sensitive diagnostic test for detecting invasive breast cancer than mammography or breast ultrasound. Breast MRI may be particularly useful in younger premenopausal women with higher density breast tissue for differentiating between dense fibroglandular breast tissue and breast malignancies. The main objective of this study was to determine the impact of preoperative breast MRI on surgical decision-making in young women with breast cancer.

Methods: A retrospective review of patients with newly diagnosed invasive breast cancer and age of ≤50 years was performed. All patients underwent physical examination, preoperative mammogram, breast ultrasound, and bilateral breast MRI. Two breast cancer surgeons reviewed the preoperative mammogram report, breast ultrasound report, and physical examination summary and were asked if they would recommend a lumpectomy, a quandrantectomy, or a mastectomy. A few weeks later, the two surgeons were shown the same information with the breast MRI report and were asked what type of surgery they would now recommend. In each case, MRI was classified by two adjudicators as having affected the surgical outcome in a positive, negative, or neutral fashion. A positive impact was defined as the situation where breast MRI detected additional disease that was not found on physical examination, mammogram, or breast ultrasound and led to an appropriate change in surgical management. A negative impact was defined as the situation where breast MRI led the surgeon to recommend more extensive surgery, with less extensive disease actually found at pathology. No impact was defined as the situation where MRI findings did not alter surgical recommendations or outcomes.

Results: Of 37 patients whose charts were reviewed, five patients were deemed to be ineligible due to having received neoadjuvant chemotherapy, having previous breast implants, or having had their tumor fully excised during biopsy. In total, 32 patients met the inclusion criteria of this study and were appropriate for analysis. The median age of our study patient population was 42 years. The pathologic diagnosis was invasive ductal carcinoma in 91% (29/32) of patients and invasive lobular carcinoma in 9% (3/32) of patients. For surgeon A, clinical management was altered in 21/32 (66%) patients, and for surgeon B, management was altered in 13/32 (41%) patients. The most common change in surgical decision-making after breast MRI was from breast-conserving surgery to a mastectomy. Mastectomy rates were similar between both surgeons after breast MRI. After reviewing the pathology results and comparing them with the breast MRI results, it was determined that breast MRI led to a positive outcome in 13/32 (41%) patients. Breast MRI led to no change in surgical management in 15/32 (47%) patients and resulted in a negative change in surgical management in 4/32 (13%) patients. Bilateral breast MRI detected a contralateral breast cancer in 2/32 (6%) patients.

Conclusions: Preoperative breast MRI alters surgical management in a significant proportion of younger women diagnosed with breast cancer. Prospective studies are needed to confirm these findings and to help determine if this change in surgical decision-making will result in improved local control.