title: Oncological benefit of primary tumor resection with high tie lymph node dissection in unresectable colorectal cancer with synchronous peritoneal metastasis: a propensity score analysis of data from a multi-institute database.
abstract: BACKGROUND
  Peritoneal metastasis is recognized as a predictor of poor prognosis in patients with colorectal cancer, and whether surgical intervention for peritoneal metastasis has any clinical benefit has remained controversial. The purposes of this study were to identify prognostic factors in cases of unresectable colorectal cancer with synchronous peritoneal metastasis and to clarify the impacts of primary tumor resection with high tie lymph node dissection.
  
  
  METHODS
  A multi-institutional retrospective analysis was conducted of 579 patients who underwent resection of the primary tumor for unresectable colorectal cancer with peritoneal metastasis between 1991 and 2007. For these 579 patients, clinicopathological variables were analyzed for prognostic significance using Cox proportional hazards model and propensity score analysis to mitigate the selection bias.
  
  
  RESULTS
  Multivariate analysis revealed hematogenous metastasis (p < 0.001), histology of the tumor (p = 0.006), postoperative chemotherapy (p < 0.001), and lymph node dissection (p = 0.001) as independent prognostic factors. In the propensity-matched cohort, patients treated with high tie lymph node dissection showed a significantly better overall survival than those with low tie lymph node dissection (median overall survival 13.0 vs. 11.5 months; p = 0.041).
  
  
  CONCLUSIONS
  It is suggested that primary tumor resection with high tie lymph node dissection favorably affects survival, even in unresectable colorectal cancer with peritoneal metastasis.
authors.affiliation: Department of Nursing, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo, Japan. furuhata@sapmed.ac.jp.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Furuhata
authors.affiliation: Department of Surgery, Surgical Oncology and Science, Sapporo Medical University, Sapporo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Okita
authors.affiliation: Department of Surgery, Surgical Oncology and Science, Sapporo Medical University, Sapporo, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Nishidate
authors.affiliation: Department of Surgery, Surgical Oncology and Science, Sapporo Medical University, Sapporo, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Hirata
authors.affiliation: Department of Public Health, Sapporo Medical University, Sapporo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ohnishi
authors.affiliation: Department of Surgical Oncology, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Department of Surgery, Tochigi Cancer Center, Utsunomiya, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kotake
authors.affiliation: Department of Surgical Oncology, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugihara
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010534:Peritoneal Neoplasms / Q000556:secondary; D011379:Prognosis; D057216:Propensity Score; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016019:Survival Analysis
keywords: Colorectal cancer; Lymph node dissection; Peritoneal metastasis; Propensity score analysis