Original articleClinical endoscopyLearning curve for EUS in gastric cancer T staging by using cumulative sum analysis

BackgroundEUS is an operator-dependent procedure and requires more technical and cognitive skills than a routine endoscopic procedure. The learning curve for the staging of gastric cancer, however, has not been evaluated.ObjectiveTo evaluate the threshold number of EUS examinations for gastric cancer T staging.DesignRetrospective study.SettingUniversity-affiliated tertiary care hospital in the Republic of Korea.PatientsFour trainees with no previous EUS experience.InterventionAnalyzing performance of EUS trainees in gastric cancer T staging by using cumulative sum (CUSUM) analysis.Main Outcome MeasurementsCUSUM plot and a minimal number of procedures for reaching a plateau.ResultsA total of 553 initial EUS examinations for treatment-naïve gastric cancers, performed by trainees, were enrolled in the study. The final T stage was determined by experts by using EUS in 332 gastric cancer cases, whereas the T stage of the other 221 lesions was determined by trainees by using EUS. The accuracy of EUS examinations performed by trainees and experts was 72.6% and 84.3%, respectively. The number of EUS examinations required to reach the first plateau in each trainee was 20, 41, 60, and 65.LimitationsRetrospective study with a relatively small number of trainees.ConclusionThe CUSUM scores of all of 4 trainees in the study reached a plateau by the 65th examination.