Measuring surgeon performance of sentinel lymph node biopsy in breast cancer treatment by cumulative sum analysis

Background This study was performed to determine if surgeons’ performance of sentinel lymph node biopsy (SLNB) for breast cancer varied with time and to devise a method to continuously evaluate that performance. Methods We retrospectively examined the SLNB experience of 13 community surgeons performing 765 SLNBs and 579 concomitant axillary dissections. False-negative rates (FNRs) were assessed for individuals and cohorts defined by caseload. Performance with time was assessed using cumulative sum (CUSUM) analysis. Results Overall, the SLN identification rate was 94.3%, and FNR was 5.3%. Each surgeon demonstrated variation in identification rate and/or FNR with time. CUSUM analysis provided an effective means to demonstrate when surgeon variation breached performance standards. Conclusions Surgeon performance of SLNB varied with time, independent of case load. CUSUM may prove to be a useful statistical tool to evaluate performance before adopting stand-alone SLNB.