Role of Greyscale Ultrasound, Colour Doppler and Ultrasound Elastography in the Evaluation of Axillary Lymph Nodes in Primary Breast Cancer - A Prospective Study

Abstract

Introduction: Breast cancer metastasizes, most commonly to lymph nodes of the axilla. Axillary lymph node metastasis has been one of the most important prognostic parameters in patients with breast malignancies. Differentiation between malignant and benign axillary lymph nodes is extremely important at an early stage because a delay in diagnosis leads to disease upstaging thus turning a curable lesion incurable. Hence early detection helps in improving outcomes and survival. Our study was intended to arrive at an accurate, early pre-operative diagnosis of lymph node metastasis by evaluating axillary lymph nodes in biopsy-proven primary breast carcinoma through non-invasive methods such as greyscale ultrasound, Colour Doppler and strain wave elastography and correlate it with histopathology. Aims: To evaluate axillary lymph nodes in primary breast cancer patients on greyscale ultrasound, Colour Doppler, strain wave elastography and correlate it with histopathology. To compare sensitivity, specificity, negative and positive predictive values of greyscale ultrasound with combined greyscale ultrasound and elastography findings. Materials and Methods: Seventy histopathologies proved primary breast carcinoma patients were included. Lymph nodes were assessed for size, shape, presence/absence of hilum, long /short axis ratio (L/S ratio), cortical thickness, cortical thickness/fatty hilum thickness ratio (C/F ratio) on greyscale ultrasound, for vascularity on Colour Doppler followed by elastography. A provisional diagnosis was made and compared with histopathology of the lymph node. Results: Our study showed that round shape, irregular nodular margins, eccentric/compressed or absent hilum, increased cortical thickness; decreased L/S ratio and increased C/F ratio were the morphological characteristics favouring malignancy. Vascular flow pattern type, resistivity index, pulsatility index and peak systolic velocity/end-diastolic velocity ratio helped in differentiating benign from malignant lymph nodes. The mean strain ratio was significantly higher in the malignant lymph node. Conclusions: Ultrasound evaluation (greyscale, colour Doppler and strain elastography) should be incorporated in the initial evaluation of suspected breast carcinoma patients as it is a cheap, radiation-free, easily accessible, reasonably accurate means of staging.