title: Cytoreductive surgery plus perioperative intraperitoneal chemotherapy in pseudomyxoma peritonei: aspects of the learning curve.
abstract: BACKGROUND
  Cytoreductive surgery (CRS) plus perioperative intraperitoneal chemotherapy is a highly invasive treatment of peritoneal metastasis and requires many surgical procedures before mastering. The aim of this study was to estimate how many procedures are needed before stabilization can be seen in surgical outcome (R1 surgery, adverse events and bleeding) in patients with pseudomyxoma peritonei (PMP).
  
  
  METHODS
  All 128 patients with PMP who were treated with CRS alone or CRS plus perioperative intraperitoneal chemotherapy between 2003 and 2008 at the Uppsala University Hospital, Uppsala, Sweden, were included. The learning curve was calculated using the partial least square (PLS) and cumulative sum control chart (CUSUM) graph. Two groups were formed based on the results of the learning curve. The learning curve plateau was considered the same as the stabilization in the CUSUM graph. Group I consisted of patients included during the learning period (n = 73) and Group II of patients treated after the learning period ended (n = 55). Comparisons between the groups were made on surgical outcome, survival and adverse events.
  
  
  RESULTS
  Stabilization was seen after 220 ± 10 procedures. A higher occurrence of R1 surgery was seen in Group II (80%) compared to Group I (48%; P = 0.0002). Overall survival increased at four years after surgery in Group II compared to Group I (80% vs. 63%; P = 0.02).
  
  
  CONCLUSIONS
  CRS plus perioperative intraperitoneal chemotherapy is a highly demanding procedure that requires more than 200 procedures before optimisation in surgical outcome is seen.
authors.affiliation: Department of Surgical Sciences, Uppsala University, S-751 85 Uppsala, Sweden. Electronic address: hakan.andreasson@surgsci.uu.se.
authors.forename: H
authors.initials: H
authors.lastname: Andréasson
authors.affiliation: Department of Surgical Sciences, Uppsala University, S-751 85 Uppsala, Sweden; Department of Surgical Sciences, Section of Transplantation Surgery, Uppsala University, Uppsala, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Lorant
authors.affiliation: Department of Surgical Sciences, Uppsala University, S-751 85 Uppsala, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Påhlman
authors.affiliation: Department of Surgical Sciences, Uppsala University, S-751 85 Uppsala, Sweden.
authors.forename: W
authors.initials: W
authors.lastname: Graf
authors.affiliation: Department of Surgical Sciences, Uppsala University, S-751 85 Uppsala, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Mahteme
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D017024:Chemotherapy, Adjuvant; D010478:Chemotherapy, Cancer, Regional Perfusion / Q000379:methods; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced; D053208:Kaplan-Meier Estimate; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period; D010529:Peritoneal Cavity; D010534:Peritoneal Neoplasms / Q000188:drug therapy* / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology / Q000601:surgery; D011553:Pseudomyxoma Peritonei / Q000188:drug therapy* / Q000601:surgery*; D012086:Reoperation; D013514:Surgical Procedures, Operative / Q000193:education*; D013548:Sweden; D016896:Treatment Outcome
keywords: Cytoreductive surgery; Learning curve; Pseudomyxoma peritonei; Survival