Sentinel lymph node biopsy with superparamagnetic iron oxide: experience in Chinese population

Abstract

Background: The combined use of radioisotope and blue dye are the gold standard in sentinel lymph node (SLN) localization in early breast cancer. Superparamagnetic iron oxide (SPIO) has recently emerged to be a non-inferior new tracer in sentinel lymph node mapping with fewer disadvantages. This study represents the first and the largest cohort of superparamagnetic iron oxide in Chinese population. Methods: From January 2016 to January 2017, a total of 100 breast cancer patients were recruited in Hong Kong and sentinel lymph node mapping was performed by SPIO. Patient characteristics, tumor characteristics and procedure success rate were analyzed. Result: Mean age of patients was 55 years old (33–83). Mean tumor size was 2.0 cm (0.4 cm–9 cm) and 40% of patients had tumors located at upper outer quadrant. Of 100 patients, 44 underwent breast conservative treatment and 56 had mastectomy. All patients received injection of SPIO one day prior to operation. A total of 98 successful SLN biopsy procedures were undertaken with 512 SLN identified. Sixty-four (12.5%) of the SLN were positive for malignancy. There were 19 patients with macrometastases, 3 with micrometastases and 8 with isolated tumor cells. Twenty one patients underwent subsequent axillary dissection. Two patients failed SLN identification with SPIO, in which one of them has received neoadjuvant chemotherapy. The success rate of SPIO in SLN localization was 98%. Conclusions: SPIO represents a feasible alternative in sentinel lymph node mapping with an equally high nodal detection rate. *An updated dataset analysis will be presented at the meeting