title: A novel tumor-node-metastasis (TNM) staging system of diffuse malignant peritoneal mesothelioma using outcome analysis of a multi-institutional database*.
abstract: BACKGROUND
  Currently, no tumor-node-metastasis (TNM) staging system exists for patients with diffuse malignant peritoneal mesothelioma (DMPM). The primary objective was to formulate a clinicopathological staging system through the identification of significant prognostic parameters.
  
  
  METHODS
  Eight international institutions with prospectively collected data on patients who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy contributed to the registry. Two hundred ninety-four patients had complete clinicopathological data and formed the basis of this staging project.
  
  
  RESULTS
  Peritoneal cancer index (PCI) was categorized into T(1) (PCI 1-10), T(2) (PCI 11-20), T(3) (PCI 21-30), and T(4) (PCI 30-39). Twenty-two patients had positive lymph nodes (N(1) ) and 12 patients had extra-abdominal metastases (M(1) ). The survival for patients with T(1) (PCI 1-10) N(0) M(0) was significantly superior to the other patients. This group of patients is therefore designated as Stage I. The survival of patients with T(2) (PCI 11-20) and T(3) (PCI 21-30), in absence of N(1) or M(1) disease, was similar. This group of patients was categorized as Stage II. The survival of patients with T(4) (PCI 30-39), N(1,) and/or M(1) was similarly poor. This group of patients was therefore categorized as Stage III. Three prognostic factors were independently associated with survival in the multivariate analysis: histological subtype, completeness of cytoreduction, and the proposed TNM staging. The 5-year survival associated with Stage I, II, and III disease was 87%, 53%, and 29%, respectively.
  
  
  CONCLUSIONS
  The proposed TNM staging system resulted in significant stratification of survival by stage when applied to the current multi-institutional registry data.
authors.affiliation: The Baird Institute for Applied Heart and Lung Surgical Research, NSW Australia. Tristan.Yan@hotmail.com
authors.forename: Tristan D
authors.initials: TD
authors.lastname: Yan
authors.forename: Marcello
authors.initials: M
authors.lastname: Deraco
authors.forename: Dominique
authors.initials: D
authors.lastname: Elias
authors.forename: Olivier
authors.initials: O
authors.lastname: Glehen
authors.forename: Edward A
authors.initials: EA
authors.lastname: Levine
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: Moran
authors.forename: David L
authors.initials: DL
authors.lastname: Morris
authors.forename: Terence C
authors.initials: TC
authors.lastname: Chua
authors.forename: Pompiliu
authors.initials: P
authors.lastname: Piso
authors.forename: Paul H
authors.initials: PH
authors.lastname: Sugarbaker
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008654:Mesothelioma / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging / Q000379:methods* / Q000592:standards; D010534:Peritoneal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome