Diagnostic Accuracy of Ultrasound and Mammography to Detect Breast Cancer in Lampang Hospital

Background: There were many women suspected breast cancer awaiting mammography in Lampang Hospital whereas ultrasound is sooner and easier. It may be possible to use ultrasound as initial imaging examination for breast cancer diagnosis.Objective: To determine diagnostic performances of mammography and ultrasound to detect breast cancer, including their affected factors.Material and method: Retrospective study was conducted on women underwent both mammography and ultrasound in Lampang Hospital between May 2013 and April 2014. BI-RADS categorization and pathological reports were recorded. Diagnostic performances were analyzedand compared between tests, age group, indication and breast density.Results: There were 1,414 women enrolled in the study (mean age 52 years, range 27- 85). Seventy-five percent was asymptomatic (1,060 cases). Imaging results were categorized as BI-RADS 1 in 239 (16.9%), BI-RADS 2 in 694 (49.1%), BI-RADS 3 in 319 (22.6%), BI-RADS 4 in 100 (7.1%), BI-RADS 5 in 57 (4.0%) and BI-RADS 6 in 5 cases (0.3%). Histopathological analyseswere obtained in 148 cases, among these 84 were found malignant. Mammography yielded sensitivity, specificity, accuracy, positive and negative predictive value for 55.2%, 92.9%, 96.7%, 96.5%, 63.9% and 99.5%. Those of ultrasound were 58.0%, 97.6%, 96.2%, 96.3%, 62.1% and99.8% whereas combined both tests yielded 59.4%, 100%, 94.1%, 94.5%, 51.9% and 100% respectively. High breast density reduced mammographic sensitivity but had no effect to ultrasound. Ultrasound had higher sensitivity than mammography in women aged <50 years or presented with palpable mass. Conclusion: Ultrasound is highly accurate and may be appropriate for initial investigation in women presented with breast mass, especially in <50 years age group or high breast density. However, combined ultrasound and mammography are recommended to prevent false negative result of single test.Keywords: Breast cancer, Mammography, Ultrasound, Accuracy, Sensitivity