Sentinel lymph node biopsy in patients with breast cancer using superparamagnetic iron oxide and a magnetometer

Abstract

Some hospitals lack facilities for radioisotopes in sentinel node biopsy. A novel method is used with a superparamagnetic tracer and a magnetometer instead of a radioisotope. Thirty patients were included in the study after obtaining IRB approval. Superparamagnetic iron oxide and patent blue dye were injected in the subareolar breast tissue. Following a few minutes of massage to promote migration of the iron tracer and blue dye throughout the lymphatic vessels, the axillary lymph nodes were detected transdermally using a handheld magnetometer and followed by standard axillary dissection in all patients. Of 30 patients evaluated, sentinel lymph nodes were identified in 90% (27/30) using both blue dye and magnetic tracer. Sentinel lymph nodes were identified using the magnetic method in 23/30 (77%) and blue dye in 24/30 (80%). There was one false-negative sentinel node, resulting in an overall sensitivity of 6/7 (86%). This is the first study to use a magnetic tracer to identify sentinel lymph nodes in patients with breast cancer. This new technique may alter the role of radioisotopes with further refinement and experience.