[Magnetic resonance imaging in preoperative diagnosis of invasive lobular carcinomas of the breast - analysis of 230 cases].

INTRODUCTION: In breast cancer patients, magnetic resonance imaging (MRI) is a supportive method characterized by high sensitivity. Its indications in the preoperative assessment are not clearly defined. More likely to benefit from preoperative MRI are younger women, women with a dense breast on mammography and patients with invasive lobular carcinoma (ILC). The aim of this study was to assess utilization of MRI and resulting benefits in preoperative tumour staging of ILC in patients treated in our institution.

METHODS: A retrospective evaluation of medical records of all patients with bioptically proven and primarily surgically treated ILC through the years 20142016.

RESULTS: Overall, 230 patients were evaluated, among them 131 (57.0%) underwent MRI. These patients were significantly younger than patients without MRI. The results of MRI were as follows: in 28.2% a small unicentric lesion, in 41.2% large infiltration or multifocality, and in 30.5% suspicion of multicentricity. The proportion of conservative surgeries and re-resections did not differ between the patients with and without MRI. The subgroup of patients with a small unicentric lesion on MRI showed a higher proportion of conservative surgeries and fewer re-resections compared to the other subgroups. In 41 women (31.3%) the MRI finding resulted in further assessments; in 29 (22.1%) an additional biopsy was done, with a malignant result in the ipsilateral breast in 8 cases and in the contralateral breast in 3 cases. The MRI finding had a substantial impact on surgery in 35 patients (26.7%) of whom it was evaluated as clinically beneficial in 23 (65.7%) cases.

CONCLUSION: At our institution, more than a half of patients with ILC undergo MRI preoperatively. The finding has an impact on the scope of the surgery in approximately one fourth of the cases, being clinically beneficial in most of them. However, a high frequency of additional imaging assessments and biopsies should be taken into account. Due to the low specificity of MRI, every suspicious lesion has to be bioptically verified to avoid inappropriate surgery and patient harm.Key words: breast cancer - invasive lobular carcinoma - magnetic resonance imaging - occult lesion - biopsy.