Will subareolar injection be a standard technique for sentinel lymph node biopsy?

Abstract

Controversy surrounds the correct injection site of radioisotope (RI) and blue dye for sentinel node biopsy (SNB) in breast cancer, and there have been some reports on the advantages of subareolar (SA) injection. We carried out a study to assess whether SA injection is useful for all patients undergoing SNB. In this prospective study, 20 patients with T1 or T2 tumors clinically node negative, were enrolled. Injection of 99mTc-phytate (0.5 mCi) was performed two times (3 to 5 days before surgery and the day of surgery) for each patient. The first RI injection was SA, and the second RI injection was subdermal (SD). The location and number of hot nodes were assessed by lymphoscintigraphy (LSG) and hand-held gamma probe. There were no patients in whom hot nodes on LSG were visualized in clearly different locations between the SA and SD injection sites. However, there were 2 patients in whom hot nodes were identified at different locations with a gamma probe. Seven patients had more hot nodes on LSG with SD injection than SA injection. Eight patients had a higher RI count of hot nodes by SD injection than SA injection. The mean RI count of hot nodes by SA injection was higher than that after SD injection. SA and SD lymphatic flow run into the same node in most patients, however, SD injection is more useful than SA injection in some patients. Though SA injection is a useful technique, it may not identify sentinel lymph nodes correctly in patients with multiple lesions or tumors in the upper outer quadrant.