title: Learning curve for robotic-assisted surgery for rectal cancer: use of the cumulative sum method.
abstract: BACKGROUND
  Few data are available to assess the learning curve for robotic-assisted surgery for rectal cancer. The aim of the present study was to evaluate the learning curve for robotic-assisted surgery for rectal cancer by a surgeon at a single institute.
  
  
  METHODS
  From December 2011 to August 2013, a total of 80 consecutive patients who underwent robotic-assisted surgery for rectal cancer performed by the same surgeon were included in this study. The learning curve was analyzed using the cumulative sum method. This method was used for all 80 cases, taking into account operative time.
  
  
  RESULTS
  Operative procedures included anterior resections in 6 patients, low anterior resections in 46 patients, intersphincteric resections in 22 patients, and abdominoperineal resections in 6 patients. Lateral lymph node dissection was performed in 28 patients. Median operative time was 280 min (range 135-683 min), and median blood loss was 17 mL (range 0-690 mL). No postoperative complications of Clavien-Dindo classification Grade III or IV were encountered. We arranged operative times and calculated cumulative sum values, allowing differentiation of three phases: phase I, Cases 1-25; phase II, Cases 26-50; and phase III, Cases 51-80.
  
  
  CONCLUSIONS
  Our data suggested three phases of the learning curve in robotic-assisted surgery for rectal cancer. The first 25 cases formed the learning phase.
authors.affiliation: Division of Colon and Rectal Surgery, Shizuoka Cancer Center Hospital, 1007 Shimonagakubo, Nagaizumi-cho, Sunto-gun, Shizuoka, 411-8777, Japan, t.yamaguchi@scchr.jp.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kinugasa
authors.forename: Akio
authors.initials: A
authors.lastname: Shiomi
authors.forename: Sumito
authors.initials: S
authors.lastname: Sato
authors.forename: Yushi
authors.initials: Y
authors.lastname: Yamakawa
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Kagawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tomioka
authors.forename: Keita
authors.initials: K
authors.lastname: Mori
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004501:Education, Medical / Q000379:methods*; D005260:Female; D013502:General Surgery / Q000193:education*; D006801:Humans; D010535:Laparoscopy / Q000193:education*; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D012004:Rectal Neoplasms / Q000601:surgery*; D012007:Rectum / Q000601:surgery*; D012371:Robotics / Q000193:education*; D066231:Surgeons / Q000592:standards