Prognostic factors in the treatment of malignant pleural mesothelioma at a large tertiary referral center

Our plain-English summary of Prognostic factors in the treatment of malignant pleural mesothelioma at a large tertiary referral center, by R.M. Flores, M. Zakowski, E. Venkatraman, et al (Journal of Thoracic Oncology, 2007).

The study

• Authors: R.M. Flores, M. Zakowski, E. Venkatraman, L. Krug, K. Rosenzweig, J. Dycoco, C. Lee, C. Yeoh, M. Bains, V. Rusch
• Journal: Journal of Thoracic Oncology
• Published: 2007;2(10):957-65
• Cited by: 179 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Most studies describing the natural history and prognostic factors for malignant pleural mesothelioma antedate accurate pathologic diagnosis, staging by computed tomography, and a universal staging system. We conducted a large single-institution analysis to identify prognostic factors and assess the association of resection with outcome in a contemporary patient population.

Methods: Patients with biopsy-proven malignant pleural mesothelioma at our institution were identified and clinical data were obtained from an institutional database. Survival and prognostic factors were analyzed by the Kaplan-Meier method, log-rank test, and Cox proportional hazards analysis. A p value <0.05 was considered statistically significant.

Results: From 1990 to 2005, 945 patients were identified: 755 men, 190 women; median age, 66 years (range, 26-93). Extrapleural pneumonectomy was performed in 208 (22%), pleurectomy/decortication in 176 (19%). Operative mortality was 4% (16/384). Multimodality therapy including surgery was associated with a median survival of 20.1 months. Significant predictors of overall survival included histology, gender, smoking, asbestos exposure, laterality, surgical resection by extrapleural pneumonectomy or pleurectomy/decortication, American Joint Committee on Cancer stage, and symptoms. A Cox model demonstrated a hazard ratio of 1.4 without surgical resection when controlling for histology, stage, gender, asbestos exposure, smoking history, symptoms, and laterality (p = 0.003).

Conclusions: In addition to tumor histology and pathologic stage, predictors of survival include gender, asbestos exposure, smoking, symptoms, laterality, and clinical stage. Surgical resection in a multimodality setting was associated with improved survival.

In plain English

This retrospective study reviewed records of 945 patients with biopsy-proven malignant pleural mesothelioma seen at Memorial Sloan-Kettering Cancer Center in New York from 1990 to 2005 (755 men, 190 women; median age 66). It looked for factors linked with survival. A history of asbestos exposure was recorded for 399 patients (43%), no exposure for 190 (20%), and unknown for 356 (37%). Fiber types were not reported. Of 384 patients whose tumor was surgically removed, 16 (4%) were operative deaths. Median survival was 12.5 months among 939 patients with survival data. Patients without an asbestos exposure history had a better prognosis in an unadjusted comparison. In a model that accounted for several factors together, that difference was not statistically significant (hazard ratio 0.95, confidence interval 0.77 to 1.19). In that model, surgical resection, female sex, nonsmoking, no chest pain, epithelioid tumor type and left-sided tumors were linked with longer survival. Median survival was 20 months with surgery plus other treatment, versus 10 months with surgery alone. The authors concluded that surgery within multimodality treatment was associated with improved survival. They noted possible selection bias and unknown confounders.

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 single-institution study of patient records, with survival analysis (Kaplan-Meier, log-rank test, Cox proportional hazards model)
• Who was studied: 945 patients with biopsy-proven malignant pleural mesothelioma at Memorial Sloan-Kettering Cancer Center, New York, 1990 to 2005: 755 men and 190 women, median age 66 years (range 26 to 93)
• Exposure: Recorded history of asbestos exposure: exposed 399 (43%), not exposed 190 (20%), unknown 356 (37%). No fiber types, jobs or doses were reported. The study's main focus was treatment (surgery and multimodality therapy) and other prognostic factors.
• Main results:
  • Operative mortality among the 384 patients who had extrapleural pneumonectomy or pleurectomy/decortication was 4% (16/384)
  • Median overall survival was 12.5 months among the 939 patients with survival data
  • In unadjusted survival analysis, female gender, lack of a smoking history, lack of a history of asbestos exposure, and left-sided tumors were associated with a better prognosis
  • In the Cox model of 939 patients, no asbestos history was not statistically significant: hazard ratio 0.95, CI 0.77 to 1.19, p 0.600
  • In the Cox model, surgical resection was associated with longer survival: hazard ratio 0.75, CI 0.62 to 0.91, p 0.003
  • In the Cox model, nonsmokers had a hazard ratio of 0.77, CI 0.61 to 0.97, p 0.023
  • In the Cox model, other factors were also linked with longer survival: female (hazard ratio 0.63, CI 0.51 to 0.77, p 0.001), no pain (0.77, CI 0.69 to 0.91, p 0.008), epithelioid histology (0.59, CI 0.46 to 0.71, p 0.001), and left side (0.84, CI 0.72 to 0.98, p 0.020)
  • Median survival was 20 months for patients who had multimodality therapy with surgery, versus 10 months for surgery alone
  • The type of surgical resection (extrapleural pneumonectomy versus pleurectomy/decortication) did not significantly influence survival
  • Patients presenting with chest pain had a median survival of 9.4 months, versus 15 months for patients without chest pain
• The authors' conclusion: The authors concluded that, in addition to tumor histology and pathologic stage, gender, asbestos exposure, smoking, symptoms, laterality and clinical stage predict survival, and that surgical resection in a multimodality setting was associated with improved survival
• Limitations the authors state:
  • Unknown confounders not included in the model may influence outcome
  • Selection bias toward earlier-staged patients and lead-time bias may account for the apparent improved survival with surgery
  • No study can prove the benefit of surgery or multimodality therapy outside a prospective randomized trial
  • The prognostic variables found (including asbestos exposure) require validation in prospective studies
  • Histology was unclassified for 483 patients because pathology slides were missing

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Staging, Biopsy, Extrapleural Pneumonectomy (EPP), Pleurectomy/Decortication (P/D), Multimodal Therapy, Median Overall Survival, Overall Survival.

Related studies

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• Extrapleural pneumonectomy for malignant pleural mesothelioma: outcomes of treatment and prognostic factors — T.D. Yan, M. Boyer, et al. (2009)
• Feasibility and safety of outpatient medical thoracoscopy at a large tertiary medical center: a collaborative medical-surgical initiative — Z.S. DePew, D. Wigle, et al. (2014)
• Important prognostic factors in patients with malignant pleural mesothelioma, managed surgically — V.W. Rusch, E.S. Venkatraman (1999)
• Factors associated with survival in a large series of patients with malignant pleural mesothelioma in New South Wales — A. Linton, N. Pavlakis, et al. (2014)
• The importance of surgical staging in the treatment of malignant pleural mesothelioma — V.W. Rusch, E. Venkatraman (1996)

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