Handheld Ultrasound for Breast Cancer Detection in Low-Resource Settings: A Systematic Review and Meta-Analysis

Background: Mammography is unavailable or infeasible in most low and middle-income countries (LMICs). The purpose of this systematic review and meta-analysis is to assess the diagnostic performance of ultrasound as a primary tool for early detection of breast cancer in LMICs. Methods: For this systematic review and meta-analysis, we comprehensively searched PubMed and SCOPUS to identify articles from January 2000- December 2018 that included data on the performance of ultrasound for detection of breast cancer. Studies evaluating handheld ultrasound as an independent detection modality for breast cancer were included. Quality assessment and bias analysis was performed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Sensitivity analyses and meta-regression were used to explore heterogeneity. Findings: Of the 4,720 identified studies, 26 were eligible for inclusion. Ultrasound had an overall pooled sensitivity and specificity of 80.1% (95% CI: 72.2%-86.3%) and 88.4% (79.8%-93.6%), respectively. When only LMIC data was considered, ultrasound maintained a diagnostic sensitivity of 89.2% and specificity of 99.1%. Meta-analysis of the included studies revealed heterogeneity. The high sensitivity of ultrasound for the detection of breast cancer was not statistically significantly different in subgroup analyses based on mean age, risk, symptoms, study design, bias level, and study setting. Interpretation: Given the increasing global burden of breast cancer and lack of access to care, including timely detection with imaging, we believe these results support the potential use of handheld ultrasound as an effective primary detection tool for breast lesions in low resource settings where mammography is unavailable. Funding Statement: The authors state: "There was no funding source for this study." Declaration of Interests: Dr. Harvey is on the scientific advisory boards of Hologic Inc. and IBM Watson Imaging. All other authors declare no competing interests. Ethics Approval Statement: The authors conducted a systematic literature review and meta-analysis following Cochrane Guidelines for Screening and Diagnostic tests and the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines.