Stratification of malignant pleural mesothelioma prognosis using recursive partitioning analysis

Our plain-English summary of Stratification of malignant pleural mesothelioma prognosis using recursive partitioning analysis, by H. Suzuki, K. Asami, T. Hirashima, et al (Lung, 2014).

The study

• Authors: H. Suzuki, K. Asami, T. Hirashima, N. Okamoto, T. Yamadori, M. Tamiya, N. Morishita, T. Shiroyama, S. Takeoka, A. Osa, Y. Azuma, K. Okishio, T. Kawaguchi, S. Atagi, I. Kawase
• Journal: Lung
• Published: 2014;192(1):191-5
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Purpose: Prognostic factors and complicated prognostic models have been proposed for malignant pleural mesothelioma (MPM). This study was designed to stratify MPM prognosis by using a simple model.

Methods: Patients diagnosed with MPM in the past 10 years (n = 122) were examined retrospectively. Data on the presence of chest pain, performance status (PS), asbestos exposure, smoking status, white blood cell count (WBC), haemoglobin (Hb) concentration, platelet count (PLT), lactate dehydronate (LD), histology, stage, and date of death or censored status were collected. After the factors were examined in the univariate analysis, recursive partitioning analysis was performed.

Results: Statistically significant factors related to survival were the type of histology, stage, PS, WBC, PLT, Hb concentration, and LD. Histology, stage, PS, and Hb concentration were used in multivariate analysis. Stage and Hb concentration showed good statistical significance, whereas PS was borderline significant. The survival analyses were stratified into five groups by PS, stage, Hb concentration, and chest pain using recursive partitioning analysis. Group A comprised patients showing the most favourable prognoses (PS 0-2 and Hb concentration >12.1 g dL(-1) or PS 0-2 and Hb concentration ≤12.1 g dL(-1) without pain), and group B comprised the remaining patients. The median overall survival in groups A and B was 563 days (95 % confidence interval [CI] 502-779) and 157 days (95 % CI 115-224), respectively (hazard ratio of 5.44 [3.46-8.53, P < 0.0001]).

Conclusions: The MPM patients with PS 0-2 and Hb concentration >12.1 or ≤12.1 g dL(-1) without chest pain had favourable prognoses.

In plain English

This retrospective study looked at 122 patients diagnosed with malignant pleural mesothelioma from January 2001 to December 2009 at two hospitals in Osaka, Japan. It aimed to find a simple way of grouping patients by expected survival. Known asbestos exposure was reported by 42 patients, but the article gives no survival result for it. Overall median survival was 408 days (95% confidence interval [CI] 307 to 532). In multivariate analysis, stage and haemoglobin concentration were statistically independent factors, while performance status (PS) was borderline significant. Recursive partitioning split patients using PS, stage, haemoglobin and chest pain. Group A had PS 0 to 2 and either haemoglobin above 12.1 g/dL, or 12.1 g/dL or less with no chest pain. Its median survival was 563 days (95% CI 502 to 779), against 157 days (95% CI 115 to 224) for all other patients (group B). The hazard ratio was 5.44 (3.46 to 8.53). The authors concluded these four factors stratified prognosis but said the model needs validation. They noted it was a small retrospective two-institution study whose models may be overfitted.

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 from two institutions, using Cox proportional hazard models and recursive partitioning (conditional inference tree) analysis to stratify survival
• Who was studied: 122 patients diagnosed with malignant pleural mesothelioma from January 2001 to December 2009 at the Osaka Prefectural Medical Center for Respiratory and Allergic Diseases or the National Hospital Organization Kinki-Chuo Chest Medical Center, Japan. Median age 69.5 years; 107 men and 15 women. Histology: 64 epithelioid, 24 sarcomatoid, 12 biphasic, 22 other or undivided.
• Exposure: Asbestos exposure was one of the variables collected. 42 of 122 patients reported known asbestos exposure. No fiber types, products, jobs or doses are given, and the study's focus was clinical prognostic factors (performance status, stage, blood counts, haemoglobin, LD, chest pain, histology, smoking), not asbestos exposure.
• Main results:
  • Events were observed in 97 of 122 patients during the study period. Median overall survival for all patients was 408 days (95% CI 307–532).
  • In univariate analysis, the statistically significant factors related to survival were type of histology, stage, PS, WBC count, platelet count, Hb concentration and LD.
  • In multivariate analysis of histology, stage, PS and Hb concentration: stage III or IV vs I or II had a hazard ratio of 2.22 [1.22–4.04], P = 0.009. Lower Hb had a hazard ratio of 1.94 [1.17–3.22], P = 0.01. PS was borderline, with a hazard ratio of 1.56 [0.999–2.44], P = 0.05007. Histology was not significant: 1.34 [0.84–2.12], P = 0.217.
  • In the recursive partitioning tree, PS was the strongest factor (PS 0–2 vs 3 or more).
  • Within the tree, patients with PS 0–2 and Hb above 12.1 g/dL had the most favourable median survival, 591 days (95% CI 512–840 days). Patients with PS 3–4 and stage IV had the worst, 103 days (95% CI 86–234 days).
  • Group A comprised patients with PS 0–2 and either Hb above 12.1 g/dL, or Hb of 12.1 g/dL or less without chest pain. Its median overall survival was 563 days (95% CI 502–779 days). Group B comprised all remaining patients, with a median overall survival of 157 days (95% CI 115–224 days). The hazard ratio was 5.44 (3.46–8.53), P less than 0.0001.
  • Dividing patients by the existing EORTC prognostic score (cutoff 1.27) gave a hazard ratio of 1.67 (95% CI 1.11–2.47, P = 0.014) between the two score groups.
  • Nonepithelioid histology was linked to poor prognosis in univariate analysis but not in the final tree model. The authors attribute this to the nonepithelioid group including many patients with poor PS or anaemia.
• The authors' conclusion: The authors concluded that MPM prognosis could be stratified by four simple factors: PS, stage, Hb concentration and chest pain. Patients with PS 0–2 and Hb above 12.1 g/dL, or 12.1 g/dL or less without chest pain, had a favourable prognosis. They stated that further studies are required to validate these findings.
• Limitations the authors state:
  • The study was retrospective, from two institutions, and had a small sample size compared with past studies.
  • Positron-emission tomography might change the staging process.
  • Wider use of effective chemotherapy such as pemetrexed might improve survival among Japanese patients.
  • The statistical models may have been overfitted by combining patients into two groups.
  • Determining an appropriate cutoff value is difficult.
  • The model needs a validation study before further conclusions can be made.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Prognosis, Performance Status, Asbestos Exposure, Histology, Multivariate Analysis, Statistical Significance, Median Overall Survival.

Related studies

• Prognostic factors in malignant pleural mesothelioma: a retrospective study — H. Suzuki, T. Hirashima, et al. (2012)
• Validation of prognostic factors in malignant pleural mesothelioma: a retrospective analysis of data from patients seeking compensation from the New South Wales Dust Diseases Board — S.C. Kao, J. Vardy, et al. (2013)
• Outcome and prognostic factors of pleural mesothelioma after surgical diagnosis and/or pleurodesis — M. Baud, S. Strano, et al. (2013)
• Supplementary prognostic variables for pleural mesothelioma: a report from the IASLC staging committee — H.I. Pass, D. Giroux, et al. (2014)
• High blood neutrophil-to-lymphocyte ratio is an indicator of poor prognosis in malignant mesothelioma patients undergoing systemic therapy — S.C. Kao, N. Pavlakis, et al. (2010)
• Cytokeratin 5/6 expression, prognosis, and association with estrogen receptor α in high-grade serous ovarian carcinoma — E.T. Taube, C. Denkert, et al. (2017)

Browse more research in Lung, or return to medical research.