title: Role of peritoneal lavage cytology and prediction of prognosis and peritoneal recurrence after curative surgery for colorectal cancer.
abstract: OBJECTIVE
  In colorectal cancer, the role of detecting free malignant cells from peritoneal lavage is currently unclear. In this study, we investigated the positive rate of free malignant cells in peritoneal lavage fluid and their predictive value for prognosis and peritoneal recurrence after a curative resection.
  
  
  METHODS
  From October 2009 to December 2011, in a prospective manner, we performed cytologic examinations of peritoneal lavage fluid obtained just after the abdominal incision from 145 patients who underwent curative surgery for colorectal cancer. We used proportional hazard regression models to analyze the predictive role of positive cytology for peritoneal recurrence and survival.
  
  
  RESULTS
  Among total 145 patients, six patients (4.1%) showed positive cytology. During the median follow-up of 32 months (range, 8-49 months), 27 patients (18.6%) developed recurrence. Among them, 5 patients (3.4%) showed peritoneal carcinomatosis. In the multivariate analysis, positive cytology was an independent predictive factor for peritoneal recurrence (hazard ratio [HR], 136.5; 95% confidence interval [CI], 12.2-1,531.9; P < 0.0001) and an independent poor prognostic factor for overall survival (HR, 11.4; 95% CI, 1.8-72.0; P = 0.009) and for disease-free survival (HR, 11.1; 95% CI, 3.4-35.8; P < 0.0001).
  
  
  CONCLUSIONS
  Positive cytology of peritoneal fluid was significantly associated with peritoneal recurrence and worse survival in patients undergoing curative surgery for colorectal cancer. Peritoneal cytology might be a useful tool for selecting patients who need intraperitoneal or systemic chemotherapy.
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
authors.forename: Sung Joon
authors.initials: SJ
authors.lastname: Bae
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
authors.forename: Ui Sup
authors.initials: US
authors.lastname: Shin
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Ki
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
authors.forename: Sang Sik
authors.initials: SS
authors.lastname: Cho
authors.affiliation: Department of Surgery, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
authors.forename: Sun Mi
authors.initials: SM
authors.lastname: Moon
authors.affiliation: Department of Pathology, Korea Cancer Center Hospital, Korea Institute of Radiological & Medical Sciences, Seoul, Korea.
authors.forename: Sun Hoo
authors.initials: SH
authors.lastname: Park
keywords: Colorectal neoplasms; Cytology; Peritoneal metastasis; Prognosis; Survival