Impact of breast MRI on surgical treatment, axillary approach, and systemic therapy for breast cancer.

Abstract:  The purpose of this study is to determine how often breast magnetic resonance imaging (MRI) brings additional information that influences management of patients with breast cancer concerning surgical treatment, axillary lymph node approach, and systemic therapy. From July 2004 to July 2005, 99 patients recently diagnosed with breast cancer in clinical stages 0, I, and II were prospectively evaluated about their therapeutic plans, at first based on usual protocol (physical examination, mammography and ultrasound) and next going through bilateral breast MR. Examinations were carried out at 1.5 T on five sequences of FSPGR 3D for 90 seconds (four post-gadolinium diethylenetriaminepenta acetic acid 0.16 mM/Kg). Parameters analyzed on MRI were extension of primary lesion; detection of multifocality, multicentricity, or contra lateral lesion; muscular or skin involvement; and presence of lymph node involvement. Pathologic confirmation of additional lesions was achieved by core or excisional biopsy. MRI made 69 additional findings in 53 patients. Fifty-one findings were true-positives (51/69 = 73.9%) including 16 larger single lesions; 18 cases of multifocality; 7 cases of multicentricity; 3 cases of contra lateral lesion; 5 cases of lymph node involvement (one of them involved medial thoracic chain); 1 with muscular involvement; 1 with skin involvement. MRI has changed previous management plans in 44.4% of 99 patients. We observed increase in mastectomies (26.8%) on axillary lymph node dissection (25%) and changes on systemic therapy (20.2%), all because of additional MRI true-positive findings. Breast MRI alters significantly the rate of mastectomy, the approach of axillary chain for staging, and the use of systemic therapy because of its accuracy in evaluating breast cancer local extent.