P164. The approach to involved anterior margins after breast conserving surgery; whether or not to re-excise

Abstract

Introduction: Breast magnetic resonance imaging (MRI) is highly sensitive in detecting invasive lobular carcinoma (ILC) of the breast. We investigate the use of breast MRI in ILC and in what proportion of patients it influences a change in the management. Methods: A prospective cohort study over a 58-months period, including all consecutive patients with ILC having breast MRI scans. Results: A total of 334 bilateral breast MRI scans were performed. 72 (21.5%) of these were for the assessment of histologically confirmed ILC and were eligible for evaluation. All these MRI scans were carried out within 2 week of patients given the diagnosis (median 5.5 days). Age range of these patients was 24e83 (median 56.5) years. 19 out of 72 patients in ILC group (26.4%) had change in their planned operation from wide local excision (WLE) to a different operation based on the MRI. This included 7 patients with multifocal cancers, 10 patients with significantly larger size of the cancer shown on the MRI than mammogram/ ultrasound and 2 patients with contralateral malignancy. Instead of simple WLE, different operations in these 19 patients included 15 mastectomies, 1 double wire guided WLE, 1 therapeutic mammoplasty and 2 bilateral operations. With regards to the size of cancers, MRI (median 25mm) correlated significantly better with histopathology (median 23mm) than mammogram (median 17mm) and ultrasound scans (median 14.5mm). Over a median 37 months follow up (range 20e78), 2.7% mortality rate (2/72) was observed with no loco-regional recurrence or distant metastases. Conclusions: One out of every four patients (26.4%) with ILC had a change in planned operation, including 20.8% needing mastectomies instead of planned WLE due to MRI findings, hence proving its usefulness in ILC.