Accuracy of Sentinel Lymph Node Biopsy in Breast Cancer Using Methylene Blue Dye Technique in a Developing Country

Abstract

Introduction: Accurate assessment of the status of the axillary lymph nodes is crucial in staging, planning treatment and determining prognosis in breast cancer. Traditionally this involved total axillary dissection. Recently, in order to decrease morbidity, the technique of Sentinel Lymph Node Biopsy (SLNB) has virtually replaced standard Axillary Lymph Node Dissection (ALND) in T1 and T2 disease with non-palpable axillary lymph nodes. The two commonly applied techniques for SLNB are radio-colloid and dye injection. In our low resource environment, we planned to use the methylene blue dye injection technique to determine the percentages of false negative as well as true positive and true negatives in order to judge the accuracy and guide applicability of this technique in our setting. Methods: We prospectively analysed data from consecutive proven T1 and T2 female breast cancer patients with non-palpable axillary lymph nodes between January and December 2018 at our institution. Exclusion criteria were patients receiving neo-adjuvant treatment, previous breast or axillary radiation, previous axillary surgery and multi-focality. All patients meeting inclusion criteria were assessed by determining the percentage of true positive and negative as well as false negative (by comparing histology of the excised sentinel lymph node with the histology of at least 10 non-sentinel nodes on permanent sections). Demographics such as age of patient, grade of carcinoma, histological subtype and size of tumours were also analysed. Results: 47 patients were studied. T1 stage accounted for 24% of the patients and T2 for 76%. The incidence of axillary metastases (both sentinel and axillary nodes) was found to be 57% (27 of 47). All patients with positive sentinel nodes had at least 2 positive non-sentinel axillary nodes. True negative was 100% (20 of 20) and true positive was also 100% (27 of 27). There were no false negatives. Conclusion: In comparison with other SLNB validation studies, we report a very accurate technique of SLNB in our setting. Our data suggest SLNB using methylene blue dye can be used as a reliable alternative to the costly technique of radioactive colloid. *Correspondence to: Navin Sookar, Department of Women’s Health, St. James Medical Complex, 112 Western Main Road, St. James, Trinidad and Tobago, Tel: (868)-688-6941; E-mail: [email protected]