Predicting survival for patients with mesothelioma: development of the PLACE prognostic model

Our plain-English summary of Predicting survival for patients with mesothelioma: development of the PLACE prognostic model, by Y. Zhang, N. Li, R. Li, et al (BMC Cancer, 2023).

The study

• Authors: Y. Zhang, N. Li, R. Li, Y. Gu, X. Liu, S. Zhang
• Journal: BMC Cancer
• Published: 2023;23(1):698
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: The overall survival of patients with mesothelioma is poor and heterogeneous. At present, the prediction model for Chinese patients needs to be improved. We sought to investigate predictors of survival in malignant pleural mesothelioma and develop prognostic prediction models.

Methods: This Two-center retrospective cohort study recruited patients with pathologically diagnosed mesothelioma at Beijing Chao-Yang Hospital and Beijing Tong-Ren Hospital. We developed a new prognostic prediction model based on COX multivariable analysis using data from patients who were recruited from June 1, 2010 to July 1, 2021 in Beijing Chao-Yang Hospital (n = 95, development cohort) and validated this model using data from patients recruited from July 18, 2014 to May 9, 2022 in Beijing Tong-Ren Hospital (n = 23, validation cohort). Receiver operating characteristic analysis was used to estimate model accuracy.

Results: The parameters in this new model included PLT > 289.5(10^9/L) (1 point), Lymphocyte > 1.785(10^9/L) (-1point), Age > 73 years old (1 point), Calcium > 2.145(mmol/L) (-1point), Eastern Cooperative Oncology Group performance status (ECOG PS) > 2 (2 points). When the sum of scores < 0, it is recognized as a low-risk group; when the score is 0 ~ 3, it is recognized as a high-risk group. The survival rate of patients in the high-risk group was significantly lower than that in the low-risk group (hazard ratio [HR], 3.878; 95% confidence interval [CI], 2.226-6.755; P < 0.001). The validation group had similar results (HR,3.574; 95%CI,1.064-12.001; P = 0.039). Furthermore, the areas under the curve 6 months after diagnosis in the two cohorts were 0.900 (95% CI: 0.839-0.962) and 0.761 (95% CI: 0.568-0.954) for development and validation cohorts, respectively.

Conclusion: We developed a simple, clinically relevant prognostic prediction model for PLACE by evaluating five variables routinely tested at the time of diagnosis. The predictive model can differentiate patients of Chinese ethnicity into different risk groups and further guide prognosis.

© 2023. The Author(s).

In plain English

This two-center retrospective cohort study from Beijing, China, built a survival score, called PLACE, for patients with mesothelioma (described in its tables as malignant pleural mesothelioma). It was developed in 95 patients at Beijing Chao-Yang Hospital (2010 to 2021) and tested in 23 patients at Beijing Tong-Ren Hospital (2014 to 2022). A clear asbestos exposure history was recorded for 26 of the 95 (27.4%) and 1 of the 23 (4.3%). The score added points for age over 73, poor performance status (ECOG PS above 2) and high platelet count, and subtracted points for higher blood calcium and lymphocyte levels. In the development group, median survival was 17 months for high-risk patients and 52 months for low-risk patients (hazard ratio 3.878; 95% CI 2.226 to 6.755). In the validation group it was 9 months for high-risk versus 11 months for low-risk patients (hazard ratio 3.574; 95% CI 1.064 to 12.001). The authors concluded the model can sort Chinese patients into risk groups. They noted small samples and short validation follow-up, and said the model was not currently generalizable beyond patients of Chinese ethnicity.

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: Two-center retrospective cohort study that developed and validated a prognostic (survival prediction) score
• Who was studied: Adults with pathologically diagnosed mesothelioma (tables describe them as malignant pleural mesothelioma patients). The development cohort was 95 patients at Beijing Chao-Yang Hospital, June 1, 2010 to July 1, 2021. The validation cohort was 23 patients at Beijing Tong-Ren Hospital, July 18, 2014 to May 9, 2022. The development cohort had been reported in an earlier study by the group.
• Exposure: Asbestos was not the subject of the study. The predictors studied were age, performance status and routine blood tests taken at diagnosis. Asbestos exposure history was recorded only as a patient characteristic: 26 of 95 (27.4%) in the development cohort had a clear history of asbestos exposure. No fiber types or jobs were reported.
• Main results:
  • In the validation cohort, only 1 of 23 patients (4.3%) had a clear history of asbestos exposure.
  • The PLACE score gave points as follows: platelets above 289.5 (10^9/L) +1; lymphocytes above 1.785 (10^9/L) -1; age over 73 +1; calcium above 2.145 mmol/L -1; ECOG PS above 2 +2.
  • A total score below 0 meant low risk. A total score of 0 to 3 meant high risk.
  • In the multivariate analysis of the development cohort, age over 73 (HR 2.017; 95% CI 1.114 to 3.652; P = 0.021) and ECOG PS (HR 3.392; 95% CI 1.288 to 8.937; P = 0.013) were independent factors for prognosis.
  • In the same multivariate analysis, three blood measures were independent factors: lymphocytes above 1.785 (HR 0.446; 95% CI 0.209 to 0.950; P = 0.036), platelets above 289.5 (HR 1.935; 95% CI 1.002 to 3.738; P = 0.049), and serum calcium above 2.145 mmol/L (HR 0.430; 95% CI 0.253 to 0.732; P = 0.002).
  • In the development cohort, the median survival of all 95 patients was 24 (12, 52) months.
  • In the development cohort, median survival was 52 (39, 86) months for the 42 low-risk patients and 17 (8, 24) months for the 53 high-risk patients.
  • In the development cohort, survival was significantly lower in the high-risk group than in the low-risk group (HR 3.878; 95% CI 2.226 to 6.755; P less than 0.001).
  • In the development cohort, the area under the curve at 6 months after diagnosis was 0.900 (95% CI 0.839 to 0.962).
  • In the validation cohort, median survival was 11 months for the 13 low-risk patients (upper range not given) and 9 (4, 10) months for the 10 high-risk patients.
  • In the validation cohort, survival was lower in the high-risk group (HR 3.574; 95% CI 1.064 to 12.001; P = 0.039).
  • In the validation cohort, the area under the curve at 6 months was 0.761 (95% CI 0.568 to 0.954).
  • In the development cohort, the existing LENT score could stratify prognosis (P = 0.017). The BRIMS score could not effectively do so (P = 0.054).
• The authors' conclusion: The authors concluded that their model, based on five variables routinely tested at diagnosis, can separate patients of Chinese ethnicity into different risk groups and guide prognosis. They stated it is not currently generalizable to the overall global population.
• Limitations the authors state:
  • Selection bias is unavoidable because the study was retrospective with small samples.
  • Patients were diagnosed over a long time span, and changes in treatment and technology may have affected outcomes.
  • The study had no genetic, molecular or imaging variables.
  • The validation cohort was small and its follow-up was short.
  • Accurate clinical stage could not be determined for most patients.
  • Patients came from only two hospitals.
  • The validation cohort's time frame did not fully overlap with the development cohort's, which leaves room for bias.
  • There are deviations between the development and validation cohorts.
  • The model is not currently generalizable beyond patients of Chinese ethnicity.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Overall Survival, Pleural Mesothelioma, Cohort Study, Performance Status, Hazard Ratio, confidence interval, Prognosis.

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