title: Postoperative peritoneal infection enhances migration and invasion capacities of tumor cells in vitro: an insight into the association between anastomotic leak and recurrence after surgery for colorectal cancer.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of postoperative peritoneal infection on proliferation, migration, and invasion capacities of cancer cells lines in vitro after surgery for colorectal cancer.
  
  
  BACKGROUND
  Anastomotic leakage is associated with higher rates of recurrence after surgery for colorectal cancer. However, the mechanisms responsible are unknown. We hypothesized that the infection-induced inflammatory response may enhance tumor progression features of residual cancer cells.
  
  
  METHODS
  Prospective matched cohort study. Patients undergoing surgery for colorectal cancer with curative intent (January 2008-March 2012) were included. Patients who had an anastomotic leak or intra-abdominal abscess were included in the infection group (n=47). For each case patient, another patient with an uncomplicated postoperative course was selected for the control group (n=47).In vitro treatments on cancer cell lines (MDA-MB-231 and SW620) were performed using baseline and postoperative serum and peritoneal fluid samples to determine cell proliferation and cell migration/invasion activities.
  
  
  RESULTS
  Postoperative peritoneal fluid from infected patients enhanced both cell migration (infection: 140±85 vs control: 94±30; P=0.016) and cell invasion (infection: 117±31 vs control: 103±16; P=0.024) capacities of cancer cell lines. With serum samples, these effects were only observed in cell migration assays (infection: 98±28 vs control: 87±17; P=0.005). Some minor activation of cell proliferation was observed by treatment with serum from infection group. Two-year cumulative disease-free survival was significantly lower in patients with postoperative peritoneal infection (infection: 77.6% vs control: 90.6%; P=0.032).
  
  
  CONCLUSIONS
  Our results suggest that postoperative peritoneal infection enhances the invasive capacity of residual tumor cells after surgery, thus facilitating their growth to recurrent tumors.
authors.affiliation: *Section of Colon and Rectal Surgery, Department of Surgery, Hospital del Mar, Barcelona, Spain †Colorectal Cancer Research Group, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain ‡Biomed Division, Leitat Technological Center, Barcelona, Spain §Consulting Service on Methodology for Biomedical Research, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Salvans
authors.forename: Xavier
authors.initials: X
authors.lastname: Mayol
authors.forename: Sandra
authors.initials: S
authors.lastname: Alonso
authors.forename: Ramon
authors.initials: R
authors.lastname: Messeguer
authors.forename: Marta
authors.initials: M
authors.lastname: Pascual
authors.forename: Sergi
authors.initials: S
authors.lastname: Mojal
authors.forename: Luis
authors.initials: L
authors.lastname: Grande
authors.forename: Miguel
authors.initials: M
authors.lastname: Pera
mesh_terms: D000368:Aged; D057868:Anastomotic Leak / Q000473:pathology*; D014408:Biomarkers, Tumor / Q000032:analysis; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D010538:Peritonitis / Q000150:complications*; D011183:Postoperative Complications / Q000473:pathology*; D011446:Prospective Studies
chemical_list: D014408:Biomarkers, Tumor