Acurácia da elastografia no diagnóstico do câncer de mama em nódulos mamários biopsiados ao ultrassom

Abstract

Introduction: Breast cancer is the most incident malignant neoplasm in women, representing 25% of cancer cases worldwide. If diagnosed at the early stages, with lesions smaller than 2 millimeters, breast cancer has better prognosis and higher cure rates. The imaging data to diagnose and screening breast cancer presents a high percentage of false positive and false negative results. Therefore, new alternative methods more accurate and less invasive have arising to investigate and define the breast pathology. Ultrasound elastography can provide additional breast disease diagnostic information, based on the tissue stiffness instead of only to consider the anatomic characteristics. It has the potential of quantifying the lesion stiffness, through a coupled software in the conventional ultrasound device, allowing evaluating different tissues according to the compressibility variation, being free of ionizing radiation. Since it is a still a recent technique, it is not used in the routine evaluation of breast nodules, in spite of being non-invasive, and can reduce the number of nodules biopsies with clinical and image evidence of benignity. Objective: Verify elastography acuity in the differential diagnosis of breast nodules diagnosed by ultrasound, comparing the differences between malignant and benign findings. Methods: Records data were obtained from patients attending HUSM Breast Ultrasound Section, between March 2013 and December 2018, which underwent ultrasound with elastography, and nodule biopsy afterwards. The histopathological results were considered as golden standard technique for comparison. The variables sex, age, location of the lesion and type of biopsy obtained were presented as a percentage, and the chi-square test was applied to evaluate the relationship between type B ultrasound data with elastography and the other variables. Results: 575 medical records were analyzed and of these, 573 cases were included in the study. Two hundred and thirty four were malignant nodules, 312 were benign nodules and in 24 samples, the results were indeterminate. A significant association was observed between the images obtained by high density elastography with malignant neoplasm (p<0,001) as well as an association between low density elastography with benign nodules (p<0,001). The sensitivity and specificity of the method were 94% and 57%, respectively, with an accuracy of 75%. Conclusion: Elastography is a method that can complement mode-B ultrasound, which will help to avoid unnecessary biopsies.