Survival analysis and development of a prognostic nomogram for patients with malignant mesothelioma in different anatomic sites

Our plain-English summary of Survival analysis and development of a prognostic nomogram for patients with malignant mesothelioma in different anatomic sites, by S. Shao, L. Sun, K. Qin, et al (Frontiers in Oncology, 2022).

The study

• Authors: S. Shao, L. Sun, K. Qin, X. Jin, T. Yi, Y. Liu, Y. Wang
• Journal: Frontiers in Oncology
• Published: 2022;12:950371
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Malignant mesothelioma (MMe) is a rare and fatal cancer with a poor prognosis. Our study aimed to compare the overall survival (OS) of MMe patients across various sites and develop a prognostic model to provide a foundation for individualized management of MMe patients.

Methods: From the Surveillance, Epidemiology, and End Results (SEER) database, 1,772 individuals with malignant mesothelioma (MMe) were identified. The X-tile software was used to identify the optimal cut-off point for continuous variables. The Kaplan-Meier method was employed to compare the survival of MMe across different sites. The Cox proportional hazards model was applied to identify the independent risk factors of overall survival (OS) and a nomogram was constructed.

Results: In the survival analysis, MMe originating from the reproductive organs and hollow organs showed a relatively better prognosis than those originating from soft tissue, solid organs, and pleura. Age, gender, location, histological type, grade of differentiation, extent of disease, lymph node status, lymph node ratio (LNR), and chemotherapy were all found to be independent risk variables for the prognosis of MMe patients (P<0.05) in a multivariate Cox analysis and were included in the construction of nomogram. In the training and testing sets, the C-index of the nomogram was 0.701 and 0.665, respectively, and the area under the ROC curve (AUROC) of the 1-, 3-, and 5-year overall survival rate was 0.749, 0.797, 0.833 and 0.730, 0.800, 0.832, respectively. The calibration curve shows that the nomogram is well-calibrated.

Conclusions: This is the first research to examine the prognosis of MMe patients based on the location. However, previous studies often focused on malignant pleural mesothelioma or malignant peritoneal mesothelioma with high incidence. Furthermore, a nomograph with good prediction efficiency was established according to the variables that influence patient survival outcomes, which provides us with a reference for clinical decision-making.

Copyright © 2022 Shao, Sun, Qin, Jin, Yi, Liu and Wang.

In plain English

This study used records from the US SEER cancer registries to compare survival of people with malignant mesothelioma by the body site where the tumor began. It also built a scoring chart (nomogram) to predict survival. It included 1,772 patients diagnosed between 2004 and 2015 who had surgery and had lymph node information recorded. In 74.6% of them the tumor began in the pleura. Asbestos exposure was not among the data collected or analyzed. Median overall survival for the whole group was 16 months (95% CI 14.811 to 17.189 months). The authors reported poor prognosis for tumors starting in soft tissue, solid organs and the pleura, and relatively better prognosis for reproductive-organ and hollow-organ tumors. Some site groups were very small; for example, only 8 patients had hollow-organ tumors. Age, sex, site, tissue type, differentiation grade, extent of disease, lymph node status, lymph node ratio and chemotherapy were independent factors linked to survival. The model's accuracy score (C-index) was 0.701 in the training set and 0.665 in the testing set, both split from the study's own patients. The authors concluded that prognosis differed by site. They noted limitations including selection bias and missing treatment details.

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 analysis of a US population-based cancer registry database (SEER), with development and validation of a prognostic model (nomogram)
• Who was studied: 1,772 patients in the SEER 18 registries (covering about 28% of the US population) with malignant mesothelioma as their first primary cancer. All were diagnosed between 2004 and 2015 and had surgery, with known lymph node and survival information. 1,322 (74.6%) had pleural tumors and 336 (19.0%) had peritoneum or retroperitoneum tumors. Much smaller numbers had tumors in male genital organs (54), solid organs (30), female genital organs (11), soft tissue (11) and hollow organs (8). 71.0% were male. The patients were split into a training set of 1,332 and a testing set of 440.
• Exposure: Not an exposure study. Asbestos exposure was not among the data extracted. The factors examined were where the tumor began (seven site groups), patient characteristics, tumor characteristics (histologic type: fibrous, epithelioid, biphasic; grade; stage; lymph nodes) and treatment (surgery type, radiotherapy, chemotherapy).
• Main results:
  • In the whole group of 1,772 patients, median overall survival was 16 months (95% CI 14.811 to 17.189 months).
  • Tumors originating in soft tissue, solid organs and the pleura had a poor prognosis. Tumors originating in reproductive organs and hollow organs had a relatively better prognosis.
  • Table 2 gives median overall survival by site:
• pleura: 13 months
• peritoneum: 33 months
• hollow organ: 57 months
• solid organ: 11 months
• male genital organ: 66 months (95% CI 0.000 to 137.333)
• soft tissue: 9 months

No value was given for female genital organs.

• In the training cohort's univariate analysis, with pleura as the reference, the hazard ratios were:
• peritoneum/retroperitoneum: 0.433 (95% CI 0.366 to 0.511)
• male genital organ: 0.262 (0.164 to 0.419)
• female genital organ: 0.056 (0.008 to 0.395)
• solid organ: 0.478 (0.282 to 0.811)
• hollow organ: 0.476 (0.178 to 1.271; P = 0.139)
• soft tissue: 1.033 (0.428 to 2.489; P = 0.943)
  • In the stepwise multivariate Cox analysis, the independent prognostic factors for overall survival were age, sex, location, histological type, differentiation grade, extent of disease, N status, lymph node ratio and chemotherapy.
  • In the training cohort's univariate analysis, women had a hazard ratio of 0.636 (95% CI 0.556 to 0.728) compared with men.
  • Radiotherapy was not significantly associated with overall survival in univariate analysis (overall P = 0.700).
  • The nomogram's C-index was 0.701 in the training set and 0.665 in the testing set. Both sets came from the study's own SEER patients.
  • The area under the curve (AUC) for predicting 1-, 3- and 5-year survival was 0.749, 0.797 and 0.833 in the development cohort, and 0.730, 0.800 and 0.832 in the validation cohort.
• The authors' conclusion: The authors concluded that prognosis of malignant mesothelioma differed by anatomical site. They identified age, sex, histological type, location, differentiation, extent of disease, N status, lymph node ratio and chemotherapy as independent factors affecting overall survival. They stated that their nomogram can be used to assess the prognosis of individual patients at different sites.
• Limitations the authors state:
  • The study was a retrospective analysis of the SEER database, so selection bias is unavoidable.
  • SEER lacks detailed clinical data such as surgical methods and specific radiotherapy and chemotherapy regimens.
  • Because of advances in treatment, recently diagnosed patients may have a better prognosis than those in the study.
  • There is no unified staging standard for mesothelioma at different locations.
  • Tumor volume was not recorded in SEER and could not be examined.
  • External validation is needed to show how the model performs in clinical practice.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Prognosis, Overall Survival, Epidemiology, SEER, Pleura, Chemotherapy, Pleural Mesothelioma.

Related studies

• Meta-Analysis of Survival and Development of a Prognostic Nomogram for Malignant Pleural Mesothelioma Treated with Systemic Chemotherapy — R. Kotecha, R. Tonse, et al. (2021)
• Development and validation of a prognostic nomogram for patients with malignant peritoneal mesothelioma — X. Wang, R. Liu, et al. (2025)
• Development of a prognostic nomogram for patients with malignant mesothelioma with bone metastasis — A. Yang, B. Tang, et al. (2023)
• Survival analysis via nomogram of surgical patients with malignant pleural mesothelioma in the Surveillance, Epidemiology, and End Results database — M. Zhuo, Q. Zheng, et al. (2019)
• Establishment of predictive nomogram and web-based survival risk calculator for malignant pleural mesothelioma: A SEER database analysis — S. Chen, W. Yu, et al. (2022)
• Predicting survival for patients with mesothelioma: development of the PLACE prognostic model — Y. Zhang, N. Li, et al. (2023)

Browse more research in Frontiers in Oncology, or return to medical research.