Preoperative magnetic resonance imaging evaluation improves breast conserving surgery rate but not local disease control in patients with ductal carcinoma in situ

Background:The role of preoperative evaluation by magnetic resonance imaging (MRI) in breast ductal carcinoma in situ (DCIS) management remains controversial.The study aims to evaluate the impact of preoperative MRI on surgery type and local disease control in DCIS patients. Methods: Patients with DCIS who received primary surgery between 2009 and 2021 in two breast centers were retrospectively included and subdivided into MRI and non-MRI cohorts.The largest diameters (LD) of target lesion measured on mammography, ultrasound, MRI, and histopathology were compared.Associations between preoperative MRI, clinicopathological characteristics, surgery type, and local recurrence were evaluated after propensity score matching (PSM).Results: A total of 1351 patients were included.The mean of LD measurements from histopathology, ultrasound, mammography, and MRI was 19.614.0mm, 21.713.0mm, 14.414.3mm,and 21.913.9mm, respectively.The overall correlation for LD measurements between MRI and histopathology ( =0.657) was stronger than that between ultrasound and histopathology (=0.574;P<0.001).LD measurements were significantly more accurate measured by MRI (51.3%) than by mammography (32.5%;P<0.001) and ultrasound (45.0%;P=0.033) compared with histopathology .After PSM for clinicopathological factors, patients in MRI cohort were more likely to receive breast conserving surgery (BCS) than those in non-MRI cohort (28.6% vs. 19.1%;P=0.003).For 227 patients planning to receive BCS as primary surgery, initial negative surgical margin was similar between MRI and non-MRI cohorts (73.6% vs. 71.9%;P=0.485).There was no difference in secondary mastectomy rate between two cohorts (22.0% vs. 23.7%;P=0.433).Patients in two cohorts have similar local recurrence rates. Conclusion:Preoperative MRI evaluation could provide accurate measurement for DCIS lesion, and was associated with a higher BCS rate in DCIS patients but did not impact local disease control.