Efficacy of sentinel lymph node biopsy with radioisotope alone and the prediction of sentinel node status using PET-CT in breast cancer.

Purpose: Sentinel lymph node biopsy (SLNB) using both a radioactive isotope (RI) and blue dye is considered highly effective; however, there were limitations with the use of both agents in some hospitals, and blue dye has been shown to have some adverse effects. Additionally, preoperative prediction of sentinel lymph node (SLN) status using the maximum standardized uptake value (SUVmax) on positron emission tomography-computed tomography (PET-CT) can help avoid unnecessary axillary dissection or SLNB. Thus, we evaluated the efficacy and oncologic safety of SLNB using an RI alone in terms of long-term outcomes and determined the association between SLN metastasis and SUVmax of the primary tumor. Methods: This retrospective study was conducted at Konyang University Hospital between March 2011 and May 2018. Overall, 142 patients with breast cancer who underwent SLNB using an RI alone were enrolled. Data on identification and false-negative rates were collected. The SUVmax of primary tumors on PET-CT were analyzed for their association with SLN metastasis. Results: The identification and false-negative rates were 98.6% and 0%, respectively. There was no axillary local recurrence in patients with negative SLN findings. The correlation between the SUVmax of the primary tumor and SLN status was significant (r=0.249, P=0.005); the cutoff value for negative SLN metastasis was <2.15. Conclusion: The single agent method using an RI is not inferior to other methods and serves as a feasible option for SLNB. And the number of excised SLNs could be minimized when the SUVmax of primary tumor is extremely low.