Combined grade and nuclear grade are prognosis predictors of epithelioid malignant peritoneal mesothelioma: a multi-institutional retrospective study

Virchows Arch. 2021 Nov;479(5):927-936. doi: 10.1007/s00428-021-03144-z. Epub 2021 Jun 24.

Abstract

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant peritoneal mesothelioma. A recently described nuclear-grading system predicted survival in patients with epithelioid malignant pleural mesothelioma. The present study was undertaken to validate this grading system in epithelioid malignant peritoneal mesothelioma (EMPM) and to compare to combined grade, including nuclear atypia, mitotic count, and tumor necrosis. Cases of EMPM, from 1995 to 2018, were analyzed from 7 French institutions from RENAPE network. Solid growth, tumor necrosis, nuclear atypia, and mitotic count were evaluated by at least 3 pathologists from the RENAPATH group. The predictions in terms of OS and PFS of nuclear grade and combined grade were analyzed. Nuclear grade was computed combining nuclear atypia score and mitotic count into a grade of I-III. Another system combining nuclear atypia score, mitotic score, and tumor necrosis was evaluated and defined as a combined grade I-III. A total of 138 cases were identified. The median follow-up was 38.9 months (range: 1.1-196.6). Nuclear and combined grades III were independently associated with a shorter OS (p < 0.05), and a shorter PFS (p < 0.05). Patients with combined grade I tumors had the best overall and progression-free survivals, in comparison to nuclear grade I. In this large multicentric study, combined grade and nuclear grade were the best independent predictors of OS and PFS in EMPM. These systems should be easily described by pathologists involved into the management of malignant peritoneal mesothelioma, because of their potential therapeutic implications.

Keywords: Biomarker; Histological prognostic factor; Malignant epithelioid peritoneal mesothelioma; Mesothelioma.

Publication types

  • Comparative Study
  • Multicenter Study
  • Observational Study
  • Validation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Biopsy
  • Cell Nucleus / pathology*
  • Epithelioid Cells / pathology*
  • Female
  • France
  • Humans
  • Male
  • Mesothelioma, Malignant / mortality
  • Mesothelioma, Malignant / pathology*
  • Mesothelioma, Malignant / therapy
  • Middle Aged
  • Mitotic Index
  • Necrosis
  • Neoplasm Grading
  • Peritoneal Neoplasms / mortality
  • Peritoneal Neoplasms / pathology*
  • Peritoneal Neoplasms / therapy
  • Predictive Value of Tests
  • Progression-Free Survival
  • Registries
  • Retrospective Studies
  • Time Factors
  • Young Adult