Background: Transoral robotic surgery (TORS) is increasingly employed as a treatment option for squamous cell carcinoma of the oropharynx.  While it has emerged as an important tool in the management of oropharyngeal squamous cell carcinoma, measures of surgical competency are needed particularly as clinical trials utilizing this technology continue to evolve.  Our objective in this study is to assess the learning curve for surgical performance using measures of surgical competency for the oncologic TORS surgeon and to identify the number of cases needed to identify the learning phase.

Methods: This is a retrospective review of all transoral robotic surgical cases performed for oropharyngeal squamous cell carcinoma at the University of Pittsburgh Medical Center between 2010 and 2015. Three surgeons performed all procedures.  Cases were excluded for non-malignancy, no tumor in the main oropharyngeal specimen, and for an inability to define margin status.  Cases were stratified by surgeon and ordered chronologically.   Surgical competency measures defined by the authors included the final margin status and time to resection of main surgical specimen.   A cumulative sum learning curve was developed for each surgeon for time to resection and margin status using the individual surgeon’s final average as the reference standard.  The inflection point of each surgeon’s curve was considered to be the point signaling the completion of the learning phase. 

Results:  There were 331 transoral robotic procedures identified.  184 cases met our inclusion criteria: 73 for Surgeon A, 42 for Surgeon B and 69 for Surgeon C.  Pathologic T-stages were T1 (93/184, 50.5%), T2 (72/184, 39.1%), T3 (15/184, 8.2%), T4 (1/184, 0.5%), Tis (1/184, 0.5%).  The primary tumor was located in the BOT (89/184, 48.4%), tonsil (79/184, 42.9%), soft palate (3/184, 1.6%), pharynx NOS (7/184, 3.8%).   There were no differences in the baseline patient characteristics between the three surgeons except the median patient age (55 years for Surgeon B vs. 60 and 59 years, p=0.01).  Mean time to resection including robot set-up was 78 minutes (standard deviation 36 minutes).  Inflection points for mean time to resection were: 25 cases (Surgeon A), 15 cases (Surgeon B), and 40 cases (Surgeon C).  The inflection points for margin status were: 25 cases (Surgeon A), 30 cases (Surgeon B), 25 cases (Surgeon C). 

Conclusion:  Using metrics of positive margin rate and time to resection of the main surgical specimen, the learning curve for TORS for squamous cell carcinoma of the oropharynx was surgeon-specific but ranges between 15 and 40 cases.