Feasibility of sentinel lymph node biopsy omission after integration of ^(18)F-FDG dedicated lymph node PET in early breast cancer: a prospective phase II trial

Objective:Sentinel lymph node biopsy(SLNB)is currently the standard of care in clinically node negative(cN0)breast cancer.The present study aimed to evaluate the negative predictive value(NPV)of 18F-FDG dedicated lymph node positron emission tomography(LymphPET)in cN0 patients.Methods:This was a prospective phase II trial divided into 2 stages(NCT04072653).In the first stage,cN0 patients underwent axillary LymphPET followed by SLNB.In the second stage,SLNB was omitted in patients with a negative preoperative axillary assessment after integration of LymphPET.Here,we report the results of the first stage.The primary outcome was the NPV of LymphPET to detect macrometastasis of lymph nodes(LN-macro).Results:A total of 189 patients with invasive breast cancer underwent LymphPET followed by surgery with definitive pathological reports.Forty patients had LN-macro,and 16 patients had only lymph node micrometastasis.Of the 131 patients with a negative LymphPET result,16 patients had LN-macro,and the NPV was 87.8%.After combined axillary imaging evaluation with ultrasound and LymphPET,100 patients were found to be both LymphPET and ultrasound negative,9 patients had LN-macro,and the NPV was 91%.Conclusions:LymphPET can be used to screen patients to potentially avoid SLNB,with an NPV>90%.The second stage of the SOAPET trial is ongoing to confirm the safety of omission of SLNB according to preoperational axillary evaluation integrating LymphPET.