title: Learning curve for total gastrectomy with D2 lymph node dissection: cumulative sum analysis for qualified surgery.
abstract: BACKGROUND
  This study was conducted to evaluate the leaning curve of D2 lymph node dissection for patients with gastric cancer in a high-volume center.
  
  
  METHODS
  The authors prospectively reviewed the data of all patients who underwent total gastrectomy with D2 lymph node dissection during a 4-year period. Retrieved lymph node number was used as a surrogate marker of oncological outcome. The retrieved lymph node number cut-off value required for satisfactory D2 lymph node dissection was defined as >25. Cumulative sum analysis was used to examine the learning curves of individual surgeons at target accuracy rates of 85%, 90%, 92.5%, 95%, and 98%.
  
  
  RESULTS
  Two junior staff surgeons performed 198 curative-intent total gastrectomies with D2 lymph node dissections during the study period; their success rates exceeded 90%. Operating time decreased with operative experience (Pearson correlation coefficient = -0.515, P < 0.001). The learning period for total gastrectomy with D2 lymph node dissection for these two junior members of staff was calculated as 23-35 cases, presuming a 92.5% success rate.
  
  
  CONCLUSIONS
  The current study suggests that the surgical learning period for D2 lymph node dissection extends to at least 23 cases or 8 months. In clinical trials containing gastric cancer surgery, the learning curve for qualified surgery from the standpoint of oncological outcome should be considered to minimize bias due to surgeon-associated factors.
authors.affiliation: Center for Gastric Cancer, National Cancer Center, 809 Madul-dong, Ilsandong-gu, Goyang-si, Gyeonggi-do 411-769, South Korea.
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Keun Won
authors.initials: KW
authors.lastname: Ryu
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Sook Ryun
authors.initials: SR
authors.lastname: Park
authors.forename: Chan Gyoo
authors.initials: CG
authors.lastname: Kim
authors.forename: Myoung Cheorl
authors.initials: MC
authors.lastname: Kook
authors.forename: Byung-Ho
authors.initials: BH
authors.lastname: Nam
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Kim
authors.forename: Jae-Moon
authors.initials: JM
authors.lastname: Bae
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence; D005260:Female; D005743:Gastrectomy; D013502:General Surgery / Q000193:education*; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010819:Physician's Role; D011379:Prognosis; D011446:Prospective Studies; D013274:Stomach Neoplasms / Q000601:surgery*; D015996:Survival Rate