A novel tumor-node-metastasis (TNM) staging system of diffuse malignant peritoneal mesothelioma using outcome analysis of a multi-institutional database*


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    Peritoneal Surface Oncology Group: Dario Baratti MD2, Shigeki Kusamura PhD2, François N. Gilly MD4, Perry Shen MD5, Faheez Mohamed MD6.



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.


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.


Peritoneal cancer index (PCI) was categorized into T1 (PCI 1-10), T2 (PCI 11-20), T3 (PCI 21-30), and T4 (PCI 30-39). Twenty-two patients had positive lymph nodes (N1) and 12 patients had extra-abdominal metastases (M1). The survival for patients with T1 (PCI 1-10) N0 M0 was significantly superior to the other patients. This group of patients is therefore designated as Stage I. The survival of patients with T2 (PCI 11-20) and T3 (PCI 21-30), in absence of N1 or M1 disease, was similar. This group of patients was categorized as Stage II. The survival of patients with T4 (PCI 30-39), N1, and/or M1 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.


The proposed TNM staging system resulted in significant stratification of survival by stage when applied to the current multi-institutional registry data. Cancer 2011. © 2010 American Cancer Society.