Development and validation of a prognostic nomogram for patients with malignant peritoneal mesothelioma

Our plain-English summary of Development and validation of a prognostic nomogram for patients with malignant peritoneal mesothelioma, by X. Wang, R. Liu, C. Wang, et al (Frontiers in Oncology, 2025).

The study

• Authors: X. Wang, R. Liu, C. Wang, J. Sun, D. Yang
• Journal: Frontiers in Oncology
• Published: 2025;15:1480197
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Malignant peritoneal mesothelioma(MPM) is a highly aggressive malignant tumor that originates from peritoneal mesothelial cells. Due to the rarity of MPM, there are few survival prediction models specifically for visualization of malignant peritoneal mesothelioma.

Objective: This study aimed to develop a nomogram for the overall survival of MPM based on the Surveillance, Epidemiology, and End Results (SEER) database and the data of Cangzhou People's Hospital were used for external verification.

Methods: Patients screened from the SEER database were divided into a training group and an internal verification group in a 7:3 ratio, with data from Cangzhou People's Hospital used as the external verification group. Cox proportional hazard regression was utilized to identify significant factors, and nomograms for 6-month, 12-month, and 18-month overall survival were developed. The performance of the nomogram was assessed using consistency index, calibration curve, and K-M curve.

Results: Age, sex, histology, surgery, tumor size, chemotherapy, differentiated and the number of organ metastases were significant risk factors (p<0.05) and were included in the nomogram.The area under the subject worker curve at 6,12,18 months overall survival (AUC) was 0.782,0.784,0.766 for the training group, 0.804,0.791,0.796 for the internal verification group, 0.767,0.749,0.783 for the external verification group. The predicted correction curve was in good agreement with the observed results. The Kaplan-Meier curves of different risk groups showed significant differences.

Conclusion: This study represents the first visual prognostic model of MPM and the initial incorporation of organ metastasis into MPM prognostic factors. The nomograph serves as a reliable tool for clinicians to personalize overall survival prediction and maximize patient benefits by identifying the most effective treatment.

Copyright © 2025 Wang, Liu, Wang, Sun and Yang.

In plain English

This retrospective study built and tested a nomogram, a scoring chart estimating a patient's chance of being alive 6, 12 and 18 months after a diagnosis of malignant peritoneal mesothelioma. The authors used US SEER cancer registry records from 2000 to 2020. Of 1,739 patients, 648 had complete data and were split into a training group of 453 and an internal validation group of 195. A further 37 patients from Cangzhou People's Hospital in China, diagnosed from 2018 to 2024, formed an external validation group. Patients' asbestos exposure was not analysed. Age, sex, histology (tissue type), surgery, tumor size, chemotherapy, differentiation and number of organ metastases were independently linked to overall survival. The chart's accuracy scores (AUC) at 6, 12 and 18 months were 0.782, 0.784 and 0.766 in the training group, 0.804, 0.791 and 0.796 in internal validation, and 0.767, 0.749 and 0.783 in external validation. The authors concluded the nomogram can be used to assess prognosis. They noted missing data, SEER's difficulty separating "no" from "unknown" values, and differences between the Chinese and US groups.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective study developing and validating a prognostic nomogram (survival prediction chart) using Cox regression, with internal and external validation
• Who was studied: Patients with malignant peritoneal mesothelioma in the US SEER 17-registry database (2000 to 2020) and at Cangzhou People's Hospital, China (2018 to 2024)
• Exposure: Asbestos exposure was not a study variable. The factors examined were clinical and treatment variables: age, gender, race, marital status, histology, differentiation, primary site, laterality, tumor size, radiotherapy, chemotherapy, surgery, TNM stage, bone, liver and lung metastasis, and number of organ metastases.
• Main results:
  • Of 1,739 SEER patients, 648 remained after excluding those with unknown clinical variables. They were randomly split into a training group (n=453) and an internal validation group (n=195). 37 Cangzhou patients formed the external validation group.
  • In multivariable Cox analysis of the training group, age, sex, histology, surgery, tumor size, chemotherapy, differentiation and number of organ metastases were independent prognostic factors for overall survival (p less than 0.05).
  • AUC values at 6, 12 and 18 months were 0.782, 0.784 and 0.766 in the training group; 0.804, 0.791 and 0.796 in the internal validation group; and 0.767, 0.749 and 0.783 in the external validation group.
  • Calibration curves showed good agreement between predicted and observed survival in all three groups.
  • Using a total-score cut-off of 1.4 from the training group, patients were divided into low- and high-risk groups. Kaplan-Meier survival curves separated these risk groups in each of the three cohorts.
  • Compared with the internal validation and training groups, the external validation group (Cangzhou) had higher proportions in the race category the authors call 'yellow race' (100%), married patients (100%) and non-operative patients (70.3%) (P less than 0.001).
  • The authors reported that prognosis after radical surgery was better than after palliative surgery or no surgery.
  • The authors stated that prognosis with two or more organ metastases was much poorer than with a single organ metastasis.
• The authors' conclusion: The authors concluded that age, sex, histology, surgery, tumor size, chemotherapy, differentiation and number of organ metastases were independent factors for overall survival. In their view, the nomogram built on these factors can be used to assess prognosis in malignant peritoneal mesothelioma, and external validation confirmed its performance across different ethnic groups.
• Limitations the authors state:
  • In the SEER database it is hard to distinguish 'no' from 'unknown' values.
  • Because data were collected retrospectively, missing values were unavoidable and affect the results.
  • No data were available on genetic tests, immunotherapy or molecular-targeted therapy.
  • Applicability worldwide is uncertain because of differences in healthcare systems, epidemiology, screening and treatment between countries.
  • The external validation group differed from the SEER groups, for example in race and marital status, which may affect the model's accuracy.
  • The nomogram still needs validation in prospective cohorts.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Mesothelial Cells, Overall Survival, Epidemiology, SEER, Histology, Chemotherapy, Kaplan-Meier Curve.

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