Comparative Study on Intraoperative Localization of Sentinel Lymph Node in Breast Cancer Patients using Tc 99m Sulfur Colloid and Blue Dye

Abstract

Background: A sentinel lymph node (SLN) is considered to be the first lymph node which is draining the tumor site. Radioactive Tc-99m labeled sulfur colloid, vital blue dye such as isosulfan blue or methylene blue, or the combination of the both is generally used for sentinel lymph node localization. In this study, we compare the sensitivity of both the methods to establish an effective method for SLN localization among early cases of breast cancer. Methods: Forty incidental cases, consulting the hospital between Jan 2015- June 2017 and diagnosed with early breast cancer (Stage T1N0M0 and T2N0M0) were subjected to sentinel lymph node detection by both radiocolloid and dye.99mTc-labeled are filtered sulfur colloid was administered intradermally in the periaerolar region in the tumor quadrant, 30 mins-1 h prior to the surgery. 1ml methylene blue dye, was administered, intraparenchymally, by circumareolar region during the surgery. All radioactive lymph nodes were removed until the background activity was less than one-tenth the ex-vivo value of hottest node. All the blue dye positive nodes, whether or not radiocolloid positive were excised and labeled accordingly and sent for histo-pathological examination. Results: SLN detection & localization was positive in 36 patients with radiocolloid and 34 patients with blue dye and in 2 patients neither of these methods showed any signs of involvement of the lymph node. The ability to identify the SLN for colloid alone, blue dye alone and the combination of both the methods was 90%, 85% and 95%, respectively. The concordance between blue dye and radiocolloid was 80%. Metastatic lymph node involvement was found in 13/38 (34.2 %) of patients. Conclusion: Both the radiocolloid and dye drains to the same SLN node however, the SLN detection ability was found to be high when both the methods are used in combination.