Diagnostic Accuracy of Sonoelastography in the Non-Invasive Diagnosis of Malignant Breast Cancer Compared to Histopathology as a Gold Standard.

ABSTRACT

OBJECTIVE: To observe the diagnostic accuracy of elastography in detecting malignant breast lesion taking strain ratio of 4.8 and histopathology as gold standard. STUDY DESIGN: Descriptive cross-sectional study. PLACE AND DURATION OF STUDY Department of Diagnostic Radiology, from March to September 2015. METHODOLOGY: Atotal of 137 patients aged 20 to 60 years with clinically palpable breast lump of any size for at least one month duration were included in this study. Patients with purely cystic lesions and those on chemotherapy or hormonal therapy were excluded. Each patient was subjected to sonoelastography followed by ultrasound guided trucut biopsy. The strain ratio cut off value of 4.8 was used to differentiate benign from malignant lesion. Consultant histopathologist's report upon the biopsy specimens was obtained. Results of sonoelastography were compared with histopathology reports. RESULTS: Mean age was 38.20 ±10.63 years. The size of the lesion ranged from 2.0 to 6.0 cm, a mean = 3.97 ±1.26 cm. The duration since the lump was noticed ranged from 12 weeks (3 months) to 20 weeks (5 months) with a mean of 15.09 ±2.56 weeks. Forty-one (29.9%) lesions were labelled malignant on sonoelastography while the actual number of malignant lesions was 35 (25.5%) on histopathology. When the results of sonoelastography were cross-tabulated with histopathology results, the number of TP(true positive), FN (false negative), FP(false positive) and TN (True negative) were 31, 4, 10 and 92 cases, respectively. It yielded 88.57% sensitivity, 90.20% specificity, 75.61% positive predictive value, 95.83% negative predictive value, 89.78% accuracy for sonoelastography in the diagnosis of malignant breast lesion taking histopathology as gold standard with an observed prevalence of malignant breast mass to be 25.55%. CONCLUSION: Using a strain ratio of 4.8, sonoelastography was found to be 88.57% sensitive, 90.20% specific, and 89.78% accurate in the diagnosis of malignant breast masses.