KjG The Korean Journal of Gastroenterology Korean J Gastroenterol 1598-9992 2233-6869 Korean Society of Gastroenterology 10.4166/kjg.2014.64.4.198 kjg-64-198 Original Article Chronological Outcomes and Learning Curve of Endoscopic Submucosal Dissection for Colorectal Tumors LeeSang Min KimEun Soo ParkKyung Sik ChoKwang Bum KimDong Choon KangYu Jin LeeYoo Jin LeeJung Min ChoiEun Sung ChoiJae Hyuk LeeHo Young Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea Correspondence to: Eun Soo Kim, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keimyung University School of Medicine, 56 Dalseong-ro, Jung-gu, Daegu 700-712, Korea. Tel: +82-53-250-8096, Fax: +82-53-250-7442, E-mail: dandy813@hanmail.net 10 2014 04 10 2014 64 4 198 205 01052014 01082014 05082014 Copyright © 2014 Korean Ophthalmological Society 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background/Aims

Endoscopic submucosal dissection (ESD) is an effective procedure for en-bloc curative resection of the colorectal tumor. As it requires high technical skills and experience in therapeutic endoscopy, it is important to understand learning curve of ESD technique. The aim of this study was to retrospectively describe the clinical results of ESD and to evaluate learning curve for the ESD of colorectal tumors.

 Methods

A total of 90 patients with 90 colorectal neoplasms, who had undergone ESD at a tertiary referral hospital from July 2009 to December 2012, were enrolled. The ESD was performed by a single endoscopist. All ESD cases were divided into three periods: first, cases 1–30; second, cases 31–60; and third, cases 61–90.

 Results

The en-bloc resection rates in third period (100%) was significantly higher than that of the first (93.3%) and second period (80%) (p=0.025). The perforation rate in third period (0%) also significantly decreased compared with that of the first (13.3%) and second period (20%) (p=0.032). To calibrate the difference of tumor size among periods, proficiency was calculated, as the procedure time per specimen area (min/cm2). The proficiency in third period (4.3) was significantly shorter than that of the first (16.8) and second period (10.2) (p=0.004).

 Conclusions

The learning curve of colorectal ESD in our study shows that at least 60 cases of ESD have to be conducted to acquire sufficient skill of degree without perforation.

 Learning curve Colon Endoscopy Dissection References Edwards BK Ward E Kohler BA Annual report to the nation on the status of cancer, 1975–2006, featuring colorectal cancer trends and impact of interventions (risk factors, screening, and treatment) to reduce future rates Cancer 2010 116544573 Byeon JS Yang DH Kim KJ Endoscopic submucosal dissection with or without snaring for colorectal neoplasms Gastrointest Endosc 2011 7410751083 Puli SR Kakugawa Y Gotoda T Antillon D Saito Y Antillon MR Meta-analysis and systematic review of colorectal endoscopic mucosal resection World J Gastroenterol 2009 1542734277 Hotta K Fujii T Saito Y Matsuda T Local recurrence after endoscopic resection of colorectal tumors Int J Colorectal Dis 2009 24225230 Tanaka S Haruma K Oka S Clinicopathologic features and endoscopic treatment of superficially spreading colorectal neoplasms larger than 20 mm Gastrointest Endosc 2001 546266 Thorlacius H Uedo N Toth E Implementation of endoscopic submucosal dissection for early colorectal neoplasms in Sweden Gastroenterol Res Pract 2013 2013758202 Hotta K Saito Y Matsuda T Shinohara T Oyama T Local recurrence and surveillance after endoscopic resection of large colorectal tumors Dig Endosc 2010 22Suppl 1S63S68 Yoshida N Naito Y Sakai K Outcome of endoscopic submucosal dissection for colorectal tumors in elderly people Int J Colorectal Dis 2010 25455461 Zhou PH Yao LQ Qin XY Endoscopic submucosal dissection for colorectal epithelial neoplasm Surg Endosc 2009 2315461551 Saito Y Sakamoto T Fukunaga S Nakajima T Kiriyama S Matsuda T Endoscopic submucosal dissection (ESD) for colorectal tumors Dig Endosc 2009 21Suppl 1S7S12 Saito Y Uraoka T Matsuda T Endoscopic treatment of large superficial colorectal tumors: a case series of 200 endoscopic submucosal dissections (with video) Gastrointest Endosc 2007 66966973 Tanaka S Oka S Kaneko I Endoscopic submucosal dissection for colorectal neoplasia: possibility of standardization Gastrointest Endosc 2007 66100107 Jamg MY Cho JW Oh WG A case of pneumorrhachis and pneumoscrotum following colon endoscopic submucosal dissection Intest Res 2013 11208212 Saito Y Fukuzawa M Matsuda T Clinical outcome of endoscopic submucosal dissection versus endoscopic mucosal re-section of large colorectal tumors as determined by curative resection Surg Endosc 2010 24343352 Uraoka T Kawahara Y Kato J Saito Y Yamamoto K Endoscopic submucosal dissection in the colorectum: present status and future prospects Dig Endosc 2009 21Suppl 1S13S16 Saito Y Otake Y Sakamoto T Indications for and technical aspects of colorectal endoscopic submucosal dissection Gut Liver 2013 7263269 Matsuda T Fujii T Saito Y Efficacy of the invasive/non-in-vasive pattern by magnifying chromoendoscopy to estimate the depth of invasion of early colorectal neoplasms Am J Gastroenterol 2008 10327002706 Ohata K Ito T Chiba H Tsuji Y Matsuhashi N Effective training system in colorectal endoscopic submucosal dissection Dig Endosc 2012 24Suppl 18489 Hotta K Oyama T Shinohara T Learning curve for endoscopic submucosal dissection of large colorectal tumors Dig Endosc 2010 22302306 Nishiyama H Isomoto H Yamaguchi N Endoscopic submucosal dissection for colorectal epithelial neoplasms Dis Colon Rectum 2010 53161168 Ohkuwa M Hosokawa K Boku N Ohtu A Tajiri H Yoshida S New endoscopic treatment for intramucosal gastric tumors using an insulated-tip diathermic knife Endoscopy 2001 33221226 Sakamoto T Saito Y Fukunaga S Nakajima T Matsuda T Learning curve associated with colorectal endoscopic submucosal dissection for endoscopists experienced in gastric endoscopic submucosal dissection Dis Colon Rectum 2011 5413071312 Tanaka S Oka S Chayama K Colorectal endoscopic submucosal dissection: present status and future perspective, including its differentiation from endoscopic mucosal resection J Gastroenterol 2008 43641651 Saito Y Uraoka T Matsuda T A pilot study to assess the safe-ty and efficacy of carbon dioxide insufflation during colorectal endoscopic submucosal dissection with the patient under con-scious sedation Gastrointest Endosc 2007 65537542 Fujishiro M Yahagi N Kakushima N Outcomes of endoscopic submucosal dissection for colorectal epithelial neoplasms in 200 consecutive cases Clin Gastroenterol Hepatol 2007 5678683 quiz 645. Isomoto H Nishiyama H Yamaguchi N Clinicopathological factors associated with clinical outcomes of endoscopic submucosal dissection for colorectal epithelial neoplasms Endoscopy 2009 41679683 Niimi K Fujishiro M Kodashima S Long-term outcomes of endoscopic submucosal dissection for colorectal epithelial neoplasms Endoscopy 2010 42723729 Tamegai Y Saito Y Masaki N Endoscopic submucosal dissection: a safe technique for colorectal tumors Endoscopy 2007 39418422 Yoshida N Wakabayashi N Kanemasa K Endoscopic submucosal dissection for colorectal tumors: technical difficulties and rate of perforation Endoscopy 2009 41758761 Huang C Huang RX Xiang P Qiu ZJ Current research status of endoscopic submucosal dissection for colorectal neoplasms Clin Invest Med 2012 35E158E164 Yoshida N Yagi N Naito Y Yoshikawa T Safe procedure in endoscopic submucosal dissection for colorectal tumors focused on preventing complications World J Gastroenterol 2010 1616881695 Kawabe T Ichinose M Omata M Successful nonsurgical management of perforation complicating endoscopic submucosal dissection of gastrointestinal epithelial neoplasms Endoscopy 2006 3810011006 Toyanaga T Man-I M Ivanov D The results and limitations of endoscopic submucosal dissection for colorectal tumors Acta Chir Iugosl 2008 551723 Park HW Byeon JS Park YS Endoscopic submucosal dissection for treatment of rectal carcinoid tumors Gastrointest Endosc 2010 72143149 Lee DS Jeon SW Park SY The feasibility of endoscopic submucosal dissection for rectal carcinoid tumors: comparison with endoscopic mucosal resection Endoscopy 2010 42647651 Moon SH Hwang JH Sohn DK Endoscopic submucosal dissection for rectal neuroendocrine (carcinoid) tumors J Laparoendosc Adv Surg Tech A 2011 21695699 Yamaguchi N Isomoto H Nishiyama H Endoscopic submucosal dissection for rectal carcinoid tumors Surg Endosc 2010 24504508 Zhou PH Yao LQ Xu MD Endoscopic submucosal dissection for rectal carcinoid tumors Zhonghua Wei Chang Wai Ke Za Zhi 2007 10319322 Figures and Tables

Learning curve of procedure time per specimen area (min/cm2). The values represent mean proficiency in each period.

Patient Demographics and Endoscopic Characteristics of the Lesions by Treatment Period

Characteristic 1st period 2nd period 3rd period p-value
Age (yr) 59.1 (36–79) 58.9 (41–76) 62.2 (35–81) 0.538
Gender (n, male:female) 14:16 18:12 21:9 0.183
Comobidity        
 Hypertension 12 (40.0) 12 (40.0) 9 (30.0) 0.650
 Type 2 DM 8 (26.7) 3 (10.0) 5 (16.7) 0.236
 CLD 2 (6.7) 0 (0.0) 1 (3.3) 0.770
 CVD 0 (0.0) 0 (0.0) 2 (6.7) 0.326
 CRD 2 (6.7) 1 (3.3) 0 (0.0) 0.770
 Others a 2 (6.7) 3 (10.0) 2 (6.7) 1.000
Location of tumors b       0.426
 Right colon 7 (23.3) 7 (23.3) 10 (33.3)  
 Left colon 3 (10.0) 6 (20.0) 7 (23.3)  
 Rectum 20 (66.7) 17 (56.7) 13 (43.3)  
Endoscopic diagnosis       0.314
 LST-G 11 (36.7) 15 (50.0) 14 (46.7)  
 LST-NG 3 (10.0) 4 (13.3) 8 (26.7)  
 Polypoid 6 (20.0) 3 (10.0) 4 (13.3)  
 Carcinoid 10 (33.3) 8 (26.7) 4 (13.3)  
Tumor size, long axis (mm) 20.9 (9–40) 24.9 (10–55) 23.8 (9–45) 0.359
Duration per ESD (day) 16.5 13.1 12.1  

Values are presented as mean (range), n (%), or mean only.

Chronologically all cases were divided according to three periods: first period, cases 1–30; second period, cases 31–60; third period, cases 61–90.

Type 2 DM, type 2 diabetes mellitus; CLD, chronic liver disease; CVD, cardiovascular disease; CRD, chronic renal disease; LST-G, laterally spreading tumor-granular type; LST-NG, laterally spreading tumor-nongranular type; ESD, endoscopic submucosal dissection.

First period: uterine cervical cancer, stomach cancer; second period: stomach cancer, hypothyroidism; third period: stomach cancer.

Right colon: cecum, ascending colon, transverse colon; left colon: descending colon, sigmoid colon.

Clinicopathological Outcomes by Treatment Period

  1st period 2nd period 3rd period p-value
Pathology       0.217
Adenoma 11 (36.7) 13 (43.3) 14 (46.7)  
Adenocarcinoma 8 (26.7) 9 (30.0) 13 (43.3)  
 Intramucosal cancer 6 (20.0) 6 (20.0) 11 (36.7)  
 Submucosal cancer        
  Shallow (<1,000 μm) 1 (3.3) 2 (6.7) 1 (3.3)  
  Deep (≥1,000 μm) 1 (3.3) 1 (3.3) 1 (3.3)  
Carcinoid tumor 9 (30.0) 8 (26.7) 2 (6.7)  
Others a 2 (6.7) 0 (0.0) 1 (3.3)  
Procedure time, min 39 (10–100) 31.5 (8–133) 15 (5–100) 0.034
En-bloc resection 28 (93.3) 24 (80.0) 30 (100.0) 0.025
R0 resection b 27 (90.0) 21 (70.0) 27 (90.0) 0.056
Perforation 4 (13.3) 6 (20.0) 0 (0.0) 0.032

Values are presented as n (%) or median (range).

Chronologically all cases were divided according to three periods: first period, cases 1–30; second period, cases 31–60; third period, cases 61–90.

First period: chronic colitis, granular cell tumor; third period: atypical cells.

En-bloc resection without tumor involvement to the margins of the resected specimen.

Clinicopathological Outcomes by Treatment Period in Colorectal Epithelial Tumors

  1st period 2nd period 3rd period p-value
Tumor size, long axis (mm), mean (range) 25.6 (20–40) 30.2 (21–55) 26.9 (20–47) 0.199
Procedure time (min), median (range) 51.6 (15–100) 47.4 (8–133) 27.7 (5–100) 0.023
En-bloc resection, n (%) 18 (90.0) 16 (72.7) 26 (100.0) 0.008
R0 resection a, n (%) 17 (85.0) 14 (63.6) 23 (88.5) 0.124
Perforation, n (%) 4 (20.0) 6 (27.3) 0 (0.0) 0.008
Proficiency (min/cm2), mean only 12.7 7.4 4.2 0.02

Chronologically all cases were divided according to three periods: first period, 20 cases; second period, 22 cases; third period, 26 cases.

En-bloc resection without tumor involvement to the margins of the resected specimen.