title: Survival and Prognostic Factors for Metachronous Peritoneal Metastasis in Patients with Colon Cancer.
abstract: BACKGROUND
  The clinical course of metachronous peritoneal metastasis of colorectal origin is poorly understood. In this retrospective study, we aimed to elucidate survival and prognostic factors for metachronous peritoneal metastasis.
  
  
  METHODS
  Patients with metachronous peritoneal metastasis after curative resection for stage I-III colon cancer were retrospectively reviewed, and the incidence and prognosis of metachronous peritoneal metastasis were investigated. Prognostic factors were identified by univariate and multivariate analyses.
  
  
  RESULTS
  Among 1582 surgically resected stage I-III colon cancer patients, 65 developed metachronous peritoneal metastasis. The 5-year cumulative incidence rate was 4.5%, and the median survival after diagnosis of peritoneal metastasis was 29.6 months. None of the patients underwent peritonectomy or intraperitoneal chemotherapy. Independent prognostic factors included right colon cancer [hazard ratio (HR) 2.69, 95% confidence interval (CI) 1.26-5.64; p = 0.011], time to metachronous peritoneal metastasis of <1 year (HR 2.02, 95% CI 1.04-3.87; p = 0.040), Peritoneal Cancer Index (PCI) >10 (HR 3.68, 95% CI 1.37-8.99; p = 0.012), concurrent metastases (HR 4.09, 95% CI 2.02-8.23; p < 0.001), and peritoneal nodule resection (HR 0.31, 95% CI 0.13-0.65; p = 0.002).
  
  
  CONCLUSIONS
  A proportion of colon cancer patients with metachronous peritoneal metastasis may benefit from combined peritoneal nodule resection and systemic chemotherapy. Right colon cancer, early peritoneal metastasis, a high PCI, and concurrent metastases negatively affected prognosis in patients with metachronous peritoneal metastasis.
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan. hinagata-tky@umin.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nagata
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hata
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Murono
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Kaneko
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yasuda
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Otani
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishikawa
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Tomomichi
authors.initials: T
authors.lastname: Kiyomatsu
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Kawai
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nozawa
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D044683:Colon, Descending; D044684:Colon, Transverse; D003110:Colonic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D010534:Peritoneal Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D015996:Survival Rate; D013997:Time Factors; D047368:Tumor Burden