Effect of the introduction of preoperative MRI scans for lobular cancer in an individual breast unit

Introduction

NICE guidelines suggest that patients with lobular breast cancer should be offered an MRI scan to measure the tumour size and to exclude multifocality and contralateral tumours. The aim of this study was to ascertain the effect of this guideline.

Methods

This guideline was introduced in January 2009. Patients with lobular cancer were selected from before and after this date. Cases were reviewed and compared for type of surgery, positive resection margins and alteration in patient management. The number of additional targeted USS and biopsies was also recorded.

Results

Sixty-nine patents were included in the study, of which 22 had preoperative MRI scans. There was no significant difference in mastectomy rates (MRI = 45.5% vs. no MRI 57.5%, P = 0.44) and no significant difference in positive margins following WLE (MRI 41% vs. no MRI 35%, P = 0.23). Of the 22 MRIs 11 additional findings were reported, six in the contralateral breast, leading to nine targeted USS and eight further core biopsies. Three of these core biopsies confirmed malignancy. Two MRI scans demonstrated multifocality and one diagnosed contralateral DCIS. Four patients’ management was altered due to the MRI result, one of these was due to an increase in size. There was one case of multifocality that was invisible on all imaging.

Conclusions

This study has shown that the guideline for preoperative MRI scanning in lobular cancer will alter the surgical management in approximately 20% of patients. An additional 20% of patients will undergo additional imaging and biopsies that do not alter management.