Trimodality Treatment of Malignant Pleural Mesothelioma: An Institutional Review

Our plain-English summary of Trimodality Treatment of Malignant Pleural Mesothelioma: An Institutional Review, by M. Kapeles, M.F. Gensheimer, D.A. Mart, et al (American Journal of Clinical Oncology, 2018).

The study

• Authors: M. Kapeles, M.F. Gensheimer, D.A. Mart, T.L. Sottero, A.S. Kusano, A. Truong, F. Farjah, G.E. Laramore, K.J. Stelzer, S.A. Patel
• Journal: American Journal of Clinical Oncology
• Published: 2018;41(1):30-35
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: Malignant pleural mesothelioma (MPM) is a deadly disease with varying treatment options. This study retrospectively describes treatment practices at the University of Washington Medical System from 1980 to 2011, and evaluates the impact of trimodality therapy and radiation (photon and neutron) on survival.

Methods: A retrospective study was conducted on patients treated for MPM. Univariate and multivariate methods were utilized to evaluate potential factors associated with survival. Treatments received and baseline characteristics were included. Survival analysis of trimodality therapy was performed using a propensity score method to control for baseline characteristics.

Results: Among 78 eligible patients, the median age at diagnosis was 59 years and the median survival was 13.7 months. On multivariate analysis, the significant predictors of improved survival were age, smoking history, location, and receipt of radiation therapy or chemotherapy. In the 48 patients receiving radiation therapy, the difference in survival between neutron therapy and non-neutron therapy patients was not statistically significant: hazard ratio, 1.20 (95% confidence interval, 0.68-2.13), P=0.52. Patients receiving trimodality therapy were more likely to have early-stage disease (60% vs. 30%) and epithelioid histology (86% vs. 58%). In a propensity score-weighted Cox proportional hazards model, trimodality therapy patients had improved overall survival, hazard ratio 0.45, P=0.004, median 14.6 versus 8.6 months.

Conclusions: Trimodality therapy was significantly associated with prolonged survival in patients with MPM, even when adjusting for baseline patient factors. Radiation therapy was associated with improved survival, but the modality of radiation therapy used was not associated with outcome.

In plain English

This retrospective study reviewed the records of 78 patients treated for malignant pleural mesothelioma at the University of Washington between 1980 and 2011. It looked at how treatment related to survival. Asbestos exposure was possible or definite in 79% of patients. Thirty-five patients (45%) received trimodality therapy. This was almost always chemotherapy, then extrapleural pneumonectomy (surgery that removes the lung), then radiation. Across all patients, median survival was 13.7 months. Survival was 31% at 2 years and 10% at 5 years. Patients given trimodality therapy more often had early-stage disease (60% vs. 30%) and epithelioid tumors (86% vs. 58%). After statistical weighting to balance these differences, trimodality patients had longer survival: hazard ratio 0.45, P = 0.004, median 14.6 versus 8.6 months. Radiation therapy was linked to better survival in the multivariate analysis. Among the 48 patients who had radiation, survival after neutron radiation did not differ significantly from survival after other radiation. The authors concluded that trimodality therapy was associated with a survival benefit in selected patients. They noted that the observational design and selection bias limit strong conclusions.

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 chart review (single-institution observational study) using Cox proportional hazards models and inverse propensity score weighting
• Who was studied: 78 patients with malignant pleural mesothelioma treated in the University of Washington hospital network, Seattle, 1980 to 2011. Most were white, male and smokers, with a median age at diagnosis of 59 years. Patients were excluded if they had another non-thoracic primary cancer, widely metastatic disease, or no treatment at UWMC.
• Exposure: The exposures studied were treatments. 68 patients (87%) received chemotherapy, 48 (62%) radiation therapy and 56 (72%) surgery. 35 (45%) received trimodality therapy, usually chemotherapy, then extrapleural pneumonectomy (EPP), then radiation. Of the patients given radiation, 52% received photons and 44% neutrons. Asbestos exposure was recorded as a baseline factor (possible or definite in 79%); no fiber types were reported.
• Main results:
  • In all 78 patients, median overall survival was 13.7 months, 2-year survival was 31% and 5-year survival was 10%.
  • On multivariate analysis, the significant predictors of survival were age, smoking history, tumor location (side), and receipt of radiation therapy or chemotherapy. For receipt of radiation therapy, the multivariate hazard ratio was 0.41 (95% CI 0.21-0.81).
  • Among the 48 patients who received radiation, neutron therapy patients had slightly worse survival than patients given other radiation. The difference was not statistically significant: hazard ratio 1.20 (95% confidence interval 0.68-2.13), P = 0.52.
  • Before adjustment, trimodality therapy patients were more likely than other patients to have early-stage disease (60% vs. 30%) and epithelioid histology (86% vs. 58%).
  • After inverse propensity score weighting, trimodality therapy patients had improved overall survival compared with patients not receiving it: hazard ratio 0.45, P = 0.004, median 14.6 versus 8.6 months.
  • Asbestos exposure was not a statistically significant predictor of survival: univariate hazard ratio 1.02 (95% CI 0.55-1.87), P = 0.96; multivariate hazard ratio 0.76 (95% CI 0.34-1.70), P = 0.51.
• The authors' conclusion: The authors concluded that, in their institutional experience, trimodality therapy was associated with a survival benefit in a selected group of patients. They found radiation therapy was associated with improved survival, and neutron therapy was not associated with a significant difference in survival compared with other radiation types. They noted the outcome for the disease remains poor.
• Limitations the authors state:
  • The study was observational, and selection bias in who received which treatment limits the ability to reach strong conclusions.
  • As a retrospective study, it was limited by the records available and by each patient's disease burden, which may have influenced treatment decisions (susceptibility bias).
  • Staging methods changed over the study period, notably the introduction of PET scans in the early 2000s.
  • Survival was measured from the date of tissue diagnosis rather than from the end of therapy, which can potentially make outcomes look more favorable.
  • The patients were only a subset of the department's mesothelioma patients; those with no treatment at the institution were excluded.
  • Chest pain, a prognostic factor in an earlier study, could not be analyzed because the information was not available for all patients.

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, Trimodality Therapy, Median Survival, Multivariate Analysis, Chemotherapy, Hazard Ratio, confidence interval, Epithelioid.

Related studies

• Trimodality treatment of malignant pleural mesothelioma — H.F. Batirel, M. Metintas, et al. (2008)
• Disparities in Compliance With National Guidelines for the Treatment of Malignant Pleural Mesothelioma — F. Espinoza-Mercado, J.D. Borgella, et al. (2019)
• Radical pleurectomy and intraoperative photodynamic therapy for malignant pleural mesothelioma — J.S. Friedberg, M.J. Culligan, et al. (2012)
• Relation between neutrophil/lymphocyte ratio and primary tumor metabolic activity in patients with malign pleural mesothelioma — B.A. Özyürek, Ö. Özmen, et al. (2018)
• Prognostic coronary surgery in a case of malignant mesothelioma previously managed with trimodality treatment — V. Dhurandhar, B.M. Robinson, et al. (2014)
• Fast neutron radiotherapy in the treatment of malignant pleural mesothelioma — S.A. Patel, A.S. Kusano, et al. (2015)

Browse more research in American Journal of Clinical Oncology, or return to medical research.