title: Positive peritoneal cytology in patients with gastric cancer: natural history and outcome of 291 patients.
abstract: BACKGROUND
  Positive peritoneal cytology is a predictor of poor survival in patients with gastric cancer. Our aim is to more clearly define the natural history of this cohort.
  
  
  METHODS
  Review of a prospectively maintained gastric cancer database of patients who had diagnostic laparoscopy with peritoneal washings. Clinicopathologic and treatment-related variables were obtained. Univariate and multivariate analyses were performed for factors associated with disease-specific survival (DSS).
  
  
  RESULTS
  From January 1993 to April 2009, a total of 1241 patients with gastric cancer underwent laparoscopy with peritoneal washings; 291 (23%) had positive cytology. There were 198 patients (68%) who had visible metastases discovered at laparoscopy (M1), and 93 patients (32%) were without gross evidence of advanced disease (M1 Cyt+). The median DSS for the entire cohort was 1 year; for M1, DSS was 0.8 years, and for M1 Cyt+ , DSS was 1.3 years. At baseline, independent predictors of worse DSS were poor performance status, M1 disease, and diffuse tumors. Among the subset of patients with M1 Cyt+ disease, performance status was the strongest independent predictor of DSS. A total of 48 of the 291 Cyt+ patients had repeat staging laparoscopy after chemotherapy. Compared with patients who had persistently positive cytology (n = 21), those who converted to negative cytology (n = 27) had a significant improvement in DSS (2.5 years vs. 1.4 years, P = 0.0003).
  
  
  CONCLUSIONS
  Patients with positive cytology as the only evidence of advanced disease exhibit a poor outcome; however, clearing of Cyt+ disease by chemotherapy is associated with a statistically significant improvement in DSS. The role for gastrectomy in patients with positive peritoneal cytology remains uncertain.
authors.affiliation: Gastric and Mixed Tumor Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Mezhir
authors.forename: Manish A
authors.initials: MA
authors.lastname: Shah
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Jacks
authors.forename: Murray F
authors.initials: MF
authors.lastname: Brennan
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Coit
authors.forename: Vivian E
authors.initials: VE
authors.lastname: Strong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003581:Cytodiagnosis; D005260:Female; D006801:Humans; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D010533:Peritoneal Lavage; D010534:Peritoneal Neoplasms / Q000556:secondary*; D010537:Peritoneum / Q000473:pathology*; D011379:Prognosis; D011446:Prospective Studies; D013274:Stomach Neoplasms / Q000473:pathology*