Improving outcomes in malignant pleural mesothelioma in an integrated health care system

Our plain-English summary of Improving outcomes in malignant pleural mesothelioma in an integrated health care system, by S. Ossowski, Y.Y. Hung, K. Banks, et al (Journal of Thoracic Disease, 2022).

The study

• Authors: S. Ossowski, Y.Y. Hung, K. Banks, D. Hsu, L. Herrinton, S. Ashiku, A. Patel, J.M. Suga, J.B. Velotta
• Journal: Journal of Thoracic Disease
• Published: 2022;14(9):3352-3363
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor that should be managed by an experienced surgical and multidisciplinary group. Our objective was to determine the impact of proficient surgeons and MPM bi-disciplinary review on outcomes of patients with MPM.

Methods: Through this cohort study, electronic medical records of 368 adult patients with MPM from 1/1/2009 to 12/31/2020 were reviewed and compared before and after MPM surgeries were regionalized to specialized surgeons and bi-disciplinary review of MPM patient treatment options. We used the Kaplan-Meier method and log-rank tests to compare survival rates by period, by treatment type, and by stage. Patients were followed from cancer diagnosis date until they died or end of study follow-up, whichever occurred first. We also conducted Cox proportional hazards regression model to examine the overall survival (OS) with adjustments for age, histology, stage, and Charlson comorbidity index (CCI).

Results: Despite similar staging, more patients received any MPM directed treatment from 2015-2020 compared with those patients from 2009-2014. Specifically, there was an increase in patients who received pleurectomy/decortication (PD) from 2015-2020 compared to those who received PD in 2009-2014. Patients with similar age, CCI, stage, and histology had an increase in OS of 12 months with multimodality therapy (surgery, systemic therapy, +/- radiation) compared to those patients who received no treatment.

Conclusions: Consolidating mesothelioma surgery to a specialized surgical team and regular bi-disciplinary review of MPM cases to determine appropriate multimodality therapy, increases the incorporation of surgical treatments in the management of patients with MPM.

2022 Journal of Thoracic Disease. All rights reserved.

In plain English

This retrospective cohort study reviewed records of 368 adults with malignant pleural mesothelioma at Kaiser Permanente Northern California. It compared 171 patients diagnosed 2009 to 2014 with 197 diagnosed 2015 to 2020. Mesothelioma surgery was moved to one specialized surgeon starting in 2014, within the earlier period; weekly two-specialty case review began in 2017. Asbestos exposure was not examined. In the later period, 124 patients (63.0%) received any mesothelioma treatment, compared with 75 (43.9%) earlier. The adjusted odds ratio for receiving treatment, later versus earlier period, was 3.25 (95% CI 1.93 to 5.49). Pleurectomy/decortication rose from 6 patients (3.5%) to 42 (21.3%). Surgical complication rates did not differ significantly between periods. Any treatment, compared with none, was associated with a lower risk of death (adjusted hazard ratio 0.57, 95% CI 0.44 to 0.73). No statistically significant overall survival difference was detected between periods (adjusted hazard ratio 0.99, 95% CI 0.77 to 1.26). The authors concluded that the changes allowed eligible patients to receive more treatment. They noted the study was observational, too small to compare the two changes separately, and open to unmeasured confounding.

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 cohort study comparing two time periods of care, using electronic medical records
• Who was studied: 368 adults with histologically confirmed malignant pleural mesothelioma at Kaiser Permanente Northern California: 171 diagnosed 2009 to 2014 and 197 diagnosed 2015 to 2020. The 54 surgical patients (10 early, 44 later) were also compared.
• Exposure: Asbestos exposure was not studied. The comparison was between two care periods (2009 to 2014 and 2015 to 2020). The authors chose these periods because mesothelioma surgery was regionalized to one surgeon at one center starting in 2014 and a weekly bi-disciplinary team review (medical oncology and thoracic surgery) started in 2017.
• Main results:
  • Any mesothelioma-directed treatment: 124 of 197 patients (63.0%) in 2015 to 2020 versus 75 of 171 (43.9%) in 2009 to 2014, P less than 0.0001
  • After adjusting for age, gender, comorbidity index, histology and stage, later-period patients had an adjusted odds ratio of 3.25 (95% CI 1.93 to 5.49) for receiving treatment compared with early-period patients
  • Pleurectomy/decortication: 42 patients (21.3%) in 2015 to 2020 versus 6 patients (3.5%) in 2009 to 2014
  • Among surgical patients, any complication within 30 days occurred in 7 of 10 (70.0%) in the early period and 26 of 44 (59.1%) in the later period, P=0.723
  • 30-day surgical mortality rose from 0% (0 of 10) before regionalization to 6.8% (3 of 44) after; the authors described this as a non-significant increase
  • In 2015 to 2020, median survival was 22.6 months (95% CI 17.6 to 37.8) for patients receiving multimodality therapy versus 4.1 months (95% CI 3.0 to 7.5) for untreated patients. In 2009 to 2014, the figures were 16.7 versus 6.9 months.
  • In the overall population, receiving any treatment versus none was associated with improved survival (adjusted hazard ratio 0.57, 95% CI 0.44 to 0.73). This is an observational association, not proof of a causal benefit.
  • No statistically significant difference in overall survival was detected between periods (adjusted hazard ratio for 2015 to 2020 versus 2009 to 2014 was 0.99, 95% CI 0.77 to 1.26, P=0.916). The authors stated that they did not observe an improvement in overall survival in all patients.
• The authors' conclusion: The authors concluded that consolidating mesothelioma surgery to specialized surgeons and holding weekly bi-disciplinary case review allowed eligible patients to receive more treatment.
• Limitations the authors state:
  • Observational design and small sample size, especially for some subgroups
  • The sample was too small to compare three periods separately (before surgical regionalization, after it, and after the bi-disciplinary review began)
  • Unmeasured confounding, such as changes in surgical technique and systemic therapies over time, could not be accounted for
  • Comorbidity index comparisons may have been affected by the switch from ICD-9 to ICD-10 coding in September 2015
  • Histologic subtypes may have been misclassified in the early period because of non-specific pathology diagnoses

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Cohort Study, Overall Survival, Histology, Staging, Pleurectomy/Decortication (P/D), Multimodal Therapy, Systemic Therapy.

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