Preoperative Axillary Ultrasound-guided Wire Localization and Lymphoscintigraphy for Sentinel Lymph Node Biopsy in Breast Cancer Patients

Background: Breast cancer has the highest incidence and mortality among female malignant tumors. Breast cancer with negative axillary lymph nodes has been diag- nosed mainly at an early stage. Sentinel lymph node biopsy (SLNB) is a standard screening technique for patients with early-stage breast cancer and clinically nega- tive lymph nodes. Lymphoscintigraphy (sentinel lymph node mapping) has been reg- ularly used as the standard method for SLNB. Today, ultrasound-guided wire locali- zation (USGWL) is a well-established technique with superior outcomes. Therefore, we attempted to determine whether preoperative UGWL and lymphoscintigraphy (blue dye and isotope injection) improve SLN detection and false-negative rate in breast cancer patients undergoing SLNB and identify clinical factors that may affect the diagnostic accuracy of axillary ultrasound (AUS). Methods: Between December 2018 and June 2019, 55 patients with clinical T1- 3N0 breast cancer eligible for an SLNB at Imam Khomeini Hospital in Tehran were included in our study. Tumor characteristics and demographic data were collect- ed by reviewing medical records and questionnaires prepared by our surgical team. The day before SLNB, all patients underwent ultrasound-guided wire localization of SLN. Lymphoscintigraphy was performed with an unfiltered 99mTc-labelled sulfur colloid peritumoral injection followed by methylene blue dye injection. The results were analyzed based on the permanent pathology report. Results: Among the 55 patients, 71.8% of SLNs were detected by wire localization, while 57.8% were found by methylene blue mapping and 59.6% by gamma probe detection. Compared with wire localization and isotope injection, the methylene blue dye technique had a low sensitivity (72.2%), while both wire localization and isotope injection reached 77.8%. The sensitivity, specificity, and accuracy of UGWL were 77.8%, 42.1%, and 65.4%, respectively. Otherwise, methylene blue dye and isotope injection accuracy was 47.3% and 50.1%, respectively. Furthermore, there was a significant relationship between BMI, tumor size, laterality, reactive ALN, and the accuracy of preoperative AUS. But there was no significant correlation between age, weight, height, tumor biopsy, tumor location, the time interval between methylene blue dye and isotope injection to surgery, and also the type of surgery to the accuracy of preoperative AUS. Conclusion: Preoperative UGWL can effectively identify SLNs compared to lym- phoscintigraphy (blue dye and isotope injection) in early breast cancer patients un- dergoing SLNB.