PD-L1 expression complements CALGB prognostic scoring system in malignant pleural mesothelioma

Our plain-English summary of PD-L1 expression complements CALGB prognostic scoring system in malignant pleural mesothelioma, by A. Avilés-Salas, L. Cabrera-Miranda, N. Hernández-Pedro, et al (Frontiers in Oncology, 2023).

The study

• Authors: A. Avilés-Salas, L. Cabrera-Miranda, N. Hernández-Pedro, D.S. Vargas-Lías, S. Samtani, W. Muñoz-Montaño, D. Motola-Kuba, L. Corrales-Rodríguez, C. Martín, A.F. Cardona, C.B. Palomares-Palomares, O. Arrieta
• Journal: Frontiers in Oncology
• Published: 2023;13:1269029
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Programmed death ligand-1 (PD-L1) expression is a predictive biomarker in patients with lung cancer, but its role in malignant pleural mesothelioma (MPM) remains unclear. Evidence suggests that higher PD-L1 expression is correlated with worse survival. CALGB is the main scoring system used to predict the benefit of chemotherapy treatment. This study aimed to determine the prognostic value of PD-L1 expression and its addition to CALGB scoring system in patients with MPM.

Methods: In this retrospective analysis, we evaluated samples with confirmed locally advanced or metastatic MPM. PD-L1 Tumor Proportional Score (TPS) was determined by immunohistochemistry at diagnosis.

Results: 73 patients were included in this study. A cutoff value of 15 was set for a high or low PD-L1 TPS. In total, 71.2% (n=52) and 28.8% (n=21) of individuals harbored low or high PD-L1 expression, respectively. PD-L1High was associated with worse median progression-free Survival (mPFS) [4.9 vs. 10.8 months; HR 2.724, 95% CI (1.44-5.14); p = 0.002] and Overall Survival (OS) [6.0 vs. 20.9 months; HR 6.87, 95% CI (3.4-8.7); p<0.001] compared to patients with PD-L1Low. Multivariate analysis confirmed that PD-L1 expression was an independent factor for PFS and OS in patients with MPM and CALGB score of 5-6.

Conclusion: PD-L1 addition to CALGB scale improves its prognostic estimation of MPM survival and should be considered in future research.

Copyright © 2023 Avilés-Salas, Cabrera-Miranda, Hernández-Pedro, Vargas-Lías, Samtani, Muñoz-Montaño, Motola-Kuba, Corrales-Rodríguez, Martín, Cardona, Palomares-Palomares and Arrieta.

In plain English

This retrospective study at the National Cancer Institute of Mexico (2009 to 2019) looked at 73 patients with advanced (stage III or IV) malignant pleural mesothelioma who had not yet been treated with chemotherapy. The authors measured PD-L1, a protein on tumor cells, in tumor samples. They classed tumors with PD-L1 on at least 15% of tumor cells as high: 21 patients had high levels and 52 had low levels. Asbestos exposure was recorded for 32 patients (43.8%); no fiber types were described. High PD-L1 went with shorter median progression-free survival (4.96 vs 10.8 months; HR 2.724, 95% CI 1.44-5.14) and shorter overall survival (HR 6.87, 95% CI 3.4-13.89). The article gives the high-PD-L1 overall survival median as 6.05 months in its text but 6.50 months in its table, against 20.9 to 20.96 months for low PD-L1. In the adjusted analysis, low PD-L1 and asbestos exposure (HR 2.11, 95% CI 1.15-3.86) were independently related to overall survival. In both lower (1-4) and higher (5-6) CALGB score groups, high PD-L1 went with shorter survival. The authors concluded that adding PD-L1 improved the CALGB score's prediction. They noted the study was retrospective and small.

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 of patient records and tumor samples at a single cancer institute
• Who was studied: 73 chemotherapy-naive patients with locally advanced or metastatic (stage III or IV) malignant pleural mesothelioma treated at the National Cancer Institute of Mexico, 2009 to 2019. Of these, 68.5% were older than 60 (n = 50) and 68.5% were male (n = 50).
• Exposure: The main factor studied was PD-L1 expression in tumor tissue, measured by immunohistochemistry, alongside the CALGB prognostic score. Asbestos exposure was recorded only as present or absent. It was present in 32 of 73 patients (43.8%). No fiber types, products or jobs were described.
• Main results:
  • Using a cut-off of 15% of tumor cells, 21 patients (28.7%) had high PD-L1 and 52 (71.2%) had low PD-L1.
  • Patients with high PD-L1 had shorter median progression-free survival than patients with low PD-L1 (4.96 vs. 10.8 months; HR 2.724; 95% CI 1.44-5.14, p=0.002).
  • Patients with high PD-L1 had shorter median overall survival than patients with low PD-L1 (HR 6.87; 95% CI 3.4-13.89, p less than 0.001). The results text gives the medians as 6.05 vs. 20.9 months. Table 3 gives 6.50 months for high PD-L1 and 20.96 months for low PD-L1.
  • In the adjusted (multivariate) analysis for overall survival, asbestos exposure (HR 2.11; 95% CI 1.15-3.86, p=0.016) and low PD-L1 (HR 0.13; 95% CI 0.06-0.28, p less than 0.001) were independently related to overall survival.
  • In the adjusted analysis for progression-free survival, a CALGB score of 5-6 (HR 1.94; 1.24-3.05; p=0.004) and low PD-L1 (HR 0.43; 0.22 to 0.84; p = 0.014) were independently associated with progression-free survival.
  • Among patients with CALGB scores 1-4, those with high PD-L1 had worse progression-free survival (6.89 vs. 12.05 months, p=0.019) and overall survival (6.34 vs. 20.96 months, p less than 0.001) than those with low PD-L1.
  • Among patients with CALGB scores 5-6, those with high PD-L1 had worse progression-free survival (4.23 vs. 8.50 months, p=0.032) and overall survival (6.50 vs 14.32 months, p=0.003) than those with low PD-L1.
• The authors' conclusion: The authors concluded that adding PD-L1 to the CALGB score was an independent prognostic factor for shorter progression-free and overall survival in advanced malignant pleural mesothelioma, and that it expanded the predictive accuracy of CALGB alone.
• Limitations the authors state:
  • The study was retrospective and had a small sample, which the authors said may limit how well the findings apply to populations with different characteristics.
  • Immune cells infiltrating the tumor were not measured, which limits understanding of the mechanism behind the results.

Topics

Medical terms in this study, explained in our Lexicon: PD-L1, Pleural Mesothelioma, Biomarker, Lung Cancer, Chemotherapy, Immunohistochemistry, Progression-Free Survival, Overall Survival.

Related studies

• Prognostic factors for malignant mesothelioma in 142 patients: validation of CALGB and EORTC prognostic scoring systems — J.G. Edwards, K.R. Abrams, et al. (2000)
• Interactions of chrysotile asbestos fibres with the complement system — J.M. Saint-Remy, P. Cole (1980)
• Prognostic Implications of the Complement Protein C1q in Gliomas — A. Mangogna, B. Belmonte, et al. (2019)
• BAP1 immunohistochemistry has limited prognostic utility as a complement of CDKN2A (p16) fluorescence in situ hybridization in malignant pleural mesothelioma — S.M. McGregor, J. McElherne, et al. (2017)
• Clinical, diagnostic and prognostic relevance of GATA3 in malignant pleural mesothelioma: a retrospective cohort study — A. Avilés-Salas, D.D. Dupont, et al. (2026)
• Trop-2 expression is associated with poor survival in pleural mesothelioma — A. Aviles-Salas, N. Hernández-Pedro, et al. (2026)

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