Gender-based Disparities in Receipt of Care and Survival in Malignant Pleural Mesothelioma

Our plain-English summary of Gender-based Disparities in Receipt of Care and Survival in Malignant Pleural Mesothelioma, by A.R. Barsky, C.A. Ahern, S. Venigalla, et al (Clinical Lung Cancer, 2020).

The study

• Authors: A.R. Barsky, C.A. Ahern, S. Venigalla, V. Verma, E.J. Anstadt, C.M. Wright, E.B. Ludmir, C.G. Berlind, W.D. Lindsay, S. Grover, K.A. Cengel, C.B. Simone
• Journal: Clinical Lung Cancer
• Published: 2020;21(6):e583-e591
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Despite accounting for a minority of malignant pleural mesothelioma (MPM) diagnoses, females may experience differential survival relative to males. It is unclear if there are gender-based differences in receipt of treatment or disease-related outcomes for patients with MPM. We therefore utilized the National Cancer Database (NCDB) to assess patterns-of-care and overall survival (OS) among patients with MPM by gender.

Materials And Methods: Patients with histologically confirmed MPM treated from 2004 to 2013 were identified from the NCDB. The association between female gender and OS was assessed using multivariable Cox proportional hazards models with propensity score matching. Patterns-of-care were assessed using multivariable logistic regression. The overall treatment effect was tested in subsets of patients by treatment strategy, histology, and clinical stage.

Results: A total of 18,799 patients were identified, of whom 14,728 (78%) were male and 4071 (22%) were female. Females were statistically more likely to present at a younger age, with fewer comorbidities, and with epithelioid histology. Despite these favorable prognostic features, women were less likely to receive surgery (P ≤ .001) or chemotherapy (P ≤ .001) compared with males. On multivariable analysis, female gender was associated with improved OS (hazard ratio, 0.83; 95% confidence interval, 0.80-0.86; P ≤ .001). Gender-based survival differences were seen across all stages, but only among patients with epithelioid (P ≤ .001) and not biphasic (P = .17) or sarcomatoid (P = 1.00) histology.

Conclusions: Surgery and chemotherapy are disproportionately underutilized in female patients with MPM. Despite this concerning disparity, female gender is independently associated with improved survival relative to males. Further research to understand factors that lead to gender disparities in MPM is warranted.

Copyright © 2020 Elsevier Inc. All rights reserved.

In plain English

This study used the US National Cancer Database to compare treatment and survival between men and women with malignant pleural mesothelioma. It included 18,799 patients treated from 2004 to 2013: 14,728 (78%) were male and 4071 (22%) were female. Asbestos exposure was not analyzed because that information was missing for more than 75% of patients. The women were younger, had fewer other illnesses, and less often had biphasic or sarcomatoid tumors. After adjustment, women were less likely than men to receive any treatment (odds ratio 0.81; 95% confidence interval 0.75-0.88), surgery (0.85; 0.78-0.94) or chemotherapy (0.80; 0.74-0.87). Even so, female gender was associated with a lower risk of death (hazard ratio 0.83; 95% confidence interval 0.80-0.86). This held after propensity score matching (hazard ratio 0.85; 0.80-0.89). The survival difference was seen across all stages but was statistically significant only for epithelioid tumors, not biphasic or sarcomatoid tumors. The authors noted they could not account for unmeasured factors such as asbestos exposure. They concluded that surgery and chemotherapy are underused in women, and that female gender is independently associated with better survival.

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 analysis of a national hospital-based cancer registry (National Cancer Database), using multivariable regression and propensity score matching
• Who was studied: 18,799 patients with malignant pleural mesothelioma in the US National Cancer Database, treated 2004 to 2013: 14,728 (78%) male and 4071 (22%) female
• Exposure: The comparison was by gender. Asbestos exposure was not analyzed because more than 75% of that data was missing, and not at random.
• Main results:
  • After adjustment, female patients were less likely than males to receive any treatment (OR 0.81; 95% CI 0.75-0.88)
  • Female patients were less likely than males to receive cancer-directed surgery (OR 0.85; 95% CI 0.78-0.94)
  • Female patients were less likely than males to receive chemotherapy (OR 0.80; 95% CI 0.74-0.87)
  • Gender did not meet the criteria for inclusion in the model for receipt of radiation therapy
  • Estimated 1- and 2-year overall survival was 45.3% and 25.7% in females, versus 38.4% and 16.3% in males
  • On multivariable analysis, female gender was associated with a decreased hazard of death relative to males (HR 0.83; 95% CI 0.80-0.86)
  • The association remained in the propensity score matched analysis (HR 0.85; 95% CI 0.80-0.89)
  • Females had a decreased hazard of death relative to males across all stages of disease
  • A statistically significant decreased hazard of death in females was found only for epithelioid histology (HR 0.80; 95% CI 0.75-0.86)
  • The difference was not statistically significant for biphasic histology (HR 0.89; 95% CI 0.75-1.05)
  • The difference was not statistically significant for sarcomatoid histology (HR 1.00; 95% CI 0.87-1.14)
  • In a sensitivity analysis that handled missing data by multiple imputation, female gender remained associated with a decreased hazard of death (HR 0.85; 95% CI 0.81-0.90)
  • The authors estimated that, in females, surgery and chemotherapy corresponded to absolute survival benefits of 6.7 and 10.8 months respectively
• The authors' conclusion: The authors concluded that surgery and chemotherapy are disproportionately underused in female patients with malignant pleural mesothelioma. Despite this, they found female gender independently associated with improved survival relative to males, and called for further research.
• Limitations the authors state:
  • Because the study is retrospective, there were baseline differences between the male and female groups that may have influenced results
  • Unmeasured confounders such as asbestos exposure, patient preferences and physician biases could not be accounted for
  • Chemotherapy was recorded only as yes or no, without type, number of cycles or duration
  • The number of women with non-epithelioid histologies was limited

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, Overall Survival, Histology, Epithelioid, Chemotherapy, Hazard Ratio, confidence interval, Biphasic Mesothelioma.

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• Malignant Peritoneal Mesothelioma: Patterns of Care and Survival in the Netherlands: A Population-Based Study — N.L. de Boer, J.P. van Kooten, et al. (2019)
• Survival by Histologic Subtype of Malignant Pleural Mesothelioma and the Impact of Surgical Resection on Overall Survival — V. Verma, C.A. Ahern, et al. (2018)
• Patterns of care and survival among patients with malignant mesothelioma in the United States — L. Enewold, E. Sharon, et al. (2017)
• Outcomes of Cytoreductive Surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) in patients older than 70 years; survival benefit at considerable morbidity and mortality — K.I. Votanopoulos, N.A. Newman, et al. (2013)
• Iterative cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for recurrent or progressive diffuse malignant peritoneal mesothelioma: clinicopathologic characteristics and survival outcome — C. Ihemelandu, L. Bijelic, et al. (2015)

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