Accuracy of Individual Descriptors and Grading of Nodal Involvement by Axillary Ultrasound in Patients of Breast Cancer

Background. Four-node sampling is a useful substitute for sentinel node biopsy in low resource settings. USG is being increasingly used as a preoperative tool to evaluate axilla. We conducted this study to assess the accuracy of different descriptors of axillary ultrasound and to formulate a model on grading of axillary involvement. Material and Methods. Thirty-four patients with clinically negative axilla underwent preoperative axillary ultrasound. The suspicious nodes were marked and details of various descriptors were noted. These nodes were sampled during axillary dissection and correlation of ultrasonographic findings with histopathological report was done to calculate accuracy of different descriptors. Based on this, a grading system of axillary lymph nodes involvement was formulated. Results. Based on the presence of various descriptors, five grades of nodal involvement could be defined. The most accurate descriptors to indicate nodal involvement were loss of hilar fat and hypoechoic internal echoes with specificity of 83% and positive predictive value of 92% each. The combination of descriptors of round shape with loss of hilar fat and hypoechoic internal echos had 100% specificity and positive predictive value. Conclusions. Grading of nodal involvement on axillary USG can be useful for selecting the most suspicious nodes for sampling during axillary dissection.