The Role of Ultrasound and Ultrasound Guided Fine Needle Aspiration Cytology of Axillary Nodes for Predicting Nodal Metastasis in Clinically Node Negative Breast Cancer Patients

Abstract

BACKGROUND: Breast cancer is the commonest cancer in women both worldwide and India, both in incidence and cancer related mortality. Axillary lymph node (LN) status is the most important prognostic correlate of disease-free and overall survival in breast cancer patients.

OBJECTIVES:To assess the axillary lymph nodes using ultrasound (US) and predicting nodal metastasis of Breast cancer in clinically node negative cases.

STUDY DESIGN:Prospective study design done from Oct 2017 to July 2019.

PARTICIPANTS: Fifty biopsy proven Breast cancer patients with clinically node negative status were included in this study.

METHOD:Axillary US of breast cancer patients was done. Each axilla was screened to identify the presence of nodes; number, size, and morphological pattern. If any one parameter was found abnormal, the node was considered to be suspicious for metastasis. All the patients underwent US guided fine needle aspiration cytology (FNAC) and were labeled as either benign/reactive or metastatic deposits of primary Breast cancer. All patients underwent surgery along with complete axillary dissection and the final histopathological examination (HPE) findings of the axillary nodes were compared with USG guided FNAC findings.

RESULTS:Mean age of patients was 48.4 year;with female:male ratio of 11.2:1. 56% patients had right Breast cancer. Suspicious features on USG i.e. rounded or dysmorphic shape, loss of fatty hilum, increased cortical thickness (>3mm) and focal cortical bulge were present in 19(38%), 20 (40%), 30(60%) and 12(24%) of LNs respectively. Out of 50 patients, 20 (40%) were labeled benign sono-graphically, out of which 19 turned out to be benign and 1 turned out to be metastatic on final HPE. Of the 30(60%) labeled as suspicious, 29 (96.7%) turned out to be malignant and 1 benign on final HPE.US combined with US guided FNAC showed the sensitivity of 93.3%,specificity of 100%, PPV of 100%, NPVof90.9%, with an accuracy of 96%.

CONCLUSION: The sonographic feature most predictive of malignancy was absence of fatty hilum followed by focal cortical bulge, rounded/dysmorphic node morphology and cortical thickness ≥ 3mm.The high sensitivity, specificity and PPV and relatively low false negative rate of USG- guided FNA of non-palpable axillary LN indicate that it is a useful procedure in the initial staging of Breast cancer.

IMPLICATIONS: Patients who have suspicious nodes on ultra-sonogram and a subsequently positive FNAC can be considered node-positive and are recommended to undergo Axillary LN Dissection at the time of primary breast surgery itself.