title: Peritoneal carcinomatosis in t4 colorectal cancer: occurrence and risk factors.
abstract: BACKGROUND
  Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy improves outcome of patients with peritoneal carcinomatosis (PC) of colorectal carcinoma. Data on the occurrence of PC in T4 colorectal carcinoma are scarce. We investigated the occurrence and risk factors for PC in these patients.
  
  
  METHODS
  This was a retrospective cohort study of patients undergoing a first resection of a T4 colorectal carcinoma in a tertiary hospital between January 2000 and December 2007. Primary outcome was the occurrence of synchronous or metachronous PC. The association with PC and several patient and tumor characteristics was evaluated using logistic regression.
  
  
  RESULTS
  A total of 200 patients underwent resection of a T4 colorectal carcinoma. Median follow-up censored for death was 66 months (18-89 months). Synchronous PC was found in 46 of 200 patients (23 %) and metachronous PC in 33 of 154 patients (21 %). In univariable analysis, factors associated with PC were: age (OR 0.97; 95 % CI 0.94-0.99; P = 0.03), radical resection (OR 0.32; 95 % CI 0.11-0.91; P = 0.03), and N stage (OR 1.63; 95 % CI 1.36-2.34; P = 0.008). In multivariable analysis, only N stage was associated with PC (OR 1.62; 95 % CI 1.12-2.34; P = 0.01). This association was not significant for the 154 patients at risk for metachronous PC.
  
  
  CONCLUSIONS
  Around 1 in 5 patients undergoing resection of a T4 colorectal carcinoma either have PC during primary resection or develop PC during follow-up. N stage was associated with PC in the entire study population. However, none of the clinical or pathological variables were associated with the risk of metachronous PC and therefore cannot be used to develop targeted surveillance strategies.
authors.affiliation: Department of Surgery, St. Antonius Hospital, Nieuwegein, The Netherlands, h.vansantvoort@umcutrecht.nl.
authors.forename: H C
authors.initials: HC
authors.lastname: van Santvoort
authors.forename: H J
authors.initials: HJ
authors.lastname: Braam
authors.forename: K R
authors.initials: KR
authors.lastname: Spekreijse
authors.forename: N R
authors.initials: NR
authors.lastname: Koning
authors.forename: P C
authors.initials: PC
authors.lastname: de Bruin
authors.forename: T S
authors.initials: TS
authors.lastname: de Vries Reilingh
authors.forename: D
authors.initials: D
authors.lastname: Boerma
authors.forename: A B
authors.initials: AB
authors.lastname: Smits
authors.forename: M J
authors.initials: MJ
authors.lastname: Wiezer
authors.forename: B
authors.initials: B
authors.lastname: van Ramshorst
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000150:complications* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D009367:Neoplasm Staging; D010534:Peritoneal Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality / Q000556:secondary; D011183:Postoperative Complications; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate