Sentinel Lymph Node Biopsy Using a Magnetic Tracer Versus Standard Radio-isotope Technique in Early Breast Cancer

The use of radioisotope with or without blue dye has long become the gold standard for sentinel lymph node localization in the management of breast cancer. The latest evidence from a number of European trials has proven that a new tracer agent, superparamagnetic iron oxide particles (SPIOs, Sienna+®), is non-inferior to the standard method of lymphatic mapping. Its application and feasibility has yet been tried in most Asian countries.

This is a prospective paired comparison trial involving both the new magnetic technique and the standard method. Patients with preoperative diagnosis of invasive carcinoma or ductal carcinoma in-situ of the breast undergoing SNOLL (Sentinel node and occult lesion localization) will be recruited from the Breast Centre of Kwong Wah Hospital. Informed consent will be obtained. All patients recruited will receive subcutaneous injection of 2 ml of Sienna+® diluted with saline to 5 ml at Breast Centre in the morning of operation, followed by five minutes of massage to the injection site. Before incision, on-table transcutaneous detection with the handheld magnetometer are carried out after at least 20 minutes from injection. Intraoperative counts of sentinel lymph nodes identified as well as the ex-vivo counts of excised nodes are also measured. All procedures are supplemented with localization by radioisotope. All lymph nodes excised will be sent for histopathological examination.