Abstract PS3-30: Peri-operative diagnostic accuracy of magnetic resonance imaging and ultrasonography in breast cancer: A meta-analysis

Abstract

Abstract Background: Accurate determination of the extent of tumor is essential when a breast-conserving therapy (BCT) is considered. Due to its high sensitivity, breast magnetic resonance imaging (MRI) is increasingly used for the accurate diagnosis and surgical planning of breast cancers. However, a recent meta-analysis showed that peri-operative evaluation with MRI leads to higher mastectomy rates in patients that could have potentially underwent BCT. Objective: The aim of this study is to compare the pre-operative diagnostic accuracy of MRI to ultrasonography (US) in breast cancer. Methods: We identified eligible studies that examined peri-operative tumor size using MRI and US and compared it to its pathological counterpart. Databases of PubMed, Embase and Google Scholar were reviewed. To keep the study homogenous, only studies evaluating invasive ductal carcinoma were included and studies evaluating ductal carcinoma in-situ and lobular ductal carcinoma were excluded. An accurate tumor estimation by MRI or US was defined as within 10 mm from the pathological tumor size. An overestimation was defined as imaging tumor size more than 10 mm larger than its pathological counterpart. Odds ratios (ORs) were calculated using a random-effects model with 2-sided p-value of 0.05 set as the significance level. Results: Twenty-five studies with 3,562 patients were included in the final analysis. MRI was 1.6-fold more accurate than US in preoperative diagnostic evaluation of breast cancer (OR 1.65; 95% confidence interval (CI) 1.24-2.18, p-value <0.00001). However, MRI was 20 folds more likely to overestimate the tumor size compared to US (OR 20.25; 95% CI 9.46-43.33; p-value <0.0001). Conclusion: MRI remains the most accurate modality for the diagnosis of breast cancer. However, it is highly likely to overestimate tumor size and can result in unnecessary mastectomies. US is a reasonable diagnostic option for most patients with breast cancer. Citation Format: Jason A Mouabbi, Zeyad Sako, Ahmed Abdalla, Tarik Hadid, Mothaffar F Rimawi. Peri-operative diagnostic accuracy of magnetic resonance imaging and ultrasonography in breast cancer: A meta-analysis [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS3-30.