Endoscopic submucosal dissection for early gastric cancer performed by supervised residents: assessment of feasibility and learning curve[*]

Background and aim: Endoscopic submucosal dissection (ESD) is feasible as a treatment for early gastric cancer (EGC) when it is performed by an experienced endoscopist. We investigated whether it was feasible for novice endoscopists to perform ESD for EGC, and how difficult it was to learn the procedure.

Methods: This case series study was performed in a cancer referral center. Three resident endoscopists, who had already learned basic procedures, performed ESD under supervision for 30 consecutive lesions, and their procedures were analyzed. The procedure was divided for assessment into (i) mucosal incision and (ii) submucosal dissection by completion of the circumferential mucosal cut. An insulated-tip knife was used for mucosal incision and submucosal dissection. A total of 90 mucosal EGCs (≤ 2 cm) without ulcers or scars in 87 patients were included. Outcomes were: rates of complete resection, complications, and self-completion; operation time; learning curve; and reasons for change of supervisor as an indicator of difficulty.

Results: Among the 90 procedures, there was a good overall complete resection rate of 93 %, with an acceptable complication rate of 4.4 %; the complications were delayed hemorrhage in two patients, and perforations in another two patients that were repaired successfully by endoscopic clipping. The self-completion rate and operation time were significantly worse for submucosal dissection than for mucosal incision. Two of the three operators showed a flat learning curve for submucosal dissection. Difficulty with the procedure was related mainly to uncontrollable hemorrhage.

Conclusions: With appropriate supervision, gastric ESD by residents is feasible, with equivalent complete resection rates and acceptable complication rates compared with those of experienced endoscopists, although there was difficulty in achieving sufficient self-completion rates in submucosal dissection. Better control of bleeding during submucosal dissection may be a key to improving the procedure.

1 Note: The article’s guarantor is N. U. The authors contributed to the study as follows: S. Y., analysis of the data, and drafting of the article; N. U., conception and design, analysis and interpretation of the data, drafting and final approval of the article; R. I., final approval of the article; N.K., H. O. and Y. F., provision of study materials and patients, and collection and collation of data; S. Y., Y. T. and K. H., provision of study materials and patients; H. I. and M. T., final approval of the article.

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1 Note: The article’s guarantor is N. U. The authors contributed to the study as follows: S. Y., analysis of the data, and drafting of the article; N. U., conception and design, analysis and interpretation of the data, drafting and final approval of the article; R. I., final approval of the article; N.K., H. O. and Y. F., provision of study materials and patients, and collection and collation of data; S. Y., Y. T. and K. H., provision of study materials and patients; H. I. and M. T., final approval of the article.