Women with malignant pleural mesothelioma have a threefold better survival rate than men

Our plain-English summary of Women with malignant pleural mesothelioma have a threefold better survival rate than men, by E. Taioli, A.S. Wolf, M. Camacho-Rivera, et al (The Annals of Thoracic Surgery, 2014).

The study

• Authors: E. Taioli, A.S. Wolf, M. Camacho-Rivera, R.M. Flores
• Journal: The Annals of Thoracic Surgery
• Published: 2014;98(3):1020-4
• Cited by: 62 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Many studies have reported that women with malignant pleural mesothelioma (MPM) experience longer survival compared with men, whereas others have not. To date, no large population-based studies have evaluated MPM outcome and its determinants in female patients.

Methods: All pathologically confirmed cases of MPM in the Surveillance, Epidemiology and End Results database from 1973 to 2009 were evaluated. Age, year of diagnosis, race, stage, cancer-directed surgery, radiation, and vital status were analyzed according to gender. Cox proportional hazard models were derived to assess the association between prognostic factors and survival.

Results: There were 14,228 cases of MPM, of which 3,196 (22%) were women. Despite similar baseline characteristics for both genders, 5-year survival was 13.4% in women and 4.5% in men (p < 0.0001). The effect of female gender on survival persisted when stratified by age (dichotomized at 50 years), stage, or race, but differed depending on treatment. Even when adjusted for age, stage, race, and treatment, female MPM patients experienced longer survival than men (hazard ratio = 0.78; 95% confidence interval 0.75 to 0.82).

Conclusions: This large data set confirms that although MPM is less common in women, they present with similar stage and are offered similar treatment options compared with men. Nevertheless, survival is far better in women compared with men, independent of confounders such as age, stage, and treatment. Differences in asbestos exposure, tumor biology, and the impact of circulating hormones on host response must be investigated to understand this survival advantage and improve prognosis for patients of both genders.

Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

In plain English

This study used the US SEER cancer registry to compare survival in women and men with malignant pleural mesothelioma diagnosed 1973 to 2009. Of 14,228 adult cases, 3,196 (22%) were women. The study did not measure asbestos exposure. Stage at diagnosis was similar for both sexes, but more women had cancer-directed surgery (28.5% versus 21.8% of men). Five-year survival was 13.4% in women and 4.5% in men. After adjustment for age, stage, race and treatment, women's hazard ratio compared with men was 0.78 (95% confidence interval 0.75 to 0.82), meaning a lower risk of death. Women survived longer in both age groups (under 50, and 50 or older), though the gap was smaller in the older group. The authors reported no gender difference among Black or other-race patients, but their table showed five-year survival of 16.3% in women and 5.6% in men of other races (unadjusted p = 0.01). The authors noted that SEER lacks chemotherapy data and detailed tumor type and uses broad stage definitions. They concluded that differences in asbestos exposure, tumor biology and hormones should be investigated to explain women's longer 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 population-based analysis of a cancer registry database (SEER), using Cox proportional hazards models
• Who was studied: 14,228 adults (aged 18 or over) with pathologically confirmed malignant mesothelioma of the pleura and lung in US SEER registries, 1973 to 2009. Of these, 11,032 were men and 3,196 (22%) were women.
• Exposure: Asbestos exposure was not measured. The factor studied was gender (women compared with men), alongside age, year of diagnosis, race, stage, cancer-directed surgery and radiation.
• Main results:
  • Five-year survival was 4.5% in men and 13.4% in women (p less than 0.0001).
  • After adjustment for age, stage, race and treatment, women had longer survival than men: hazard ratio 0.78 (95% confidence interval 0.75 to 0.82).
  • Stage at diagnosis was similar for men and women. A higher proportion of women had cancer-directed surgery: 912 of 3,196 (28.5%) women versus 2,400 of 11,032 (21.8%) men (Table 1).
  • Women survived longer in each age category. The difference was less marked in patients aged 50 or older than in those under 50. Five-year survival under age 50 was 17.3% for men and 38.6% for women. At 50 or older it was 3.7% for men and 9.8% for women (Table 2).
  • The authors wrote that no gender differences in survival were observed among Black patients or patients of other races.
  • Table 2 does not fully match that statement for the other-races group. Five-year survival was 5.6% in men and 16.3% in women, with an unadjusted (univariate) p value of 0.01. One-year survival in that group was 35.8% in men and 42.4% in women (p = 0.4). For Black patients, five-year survival was 8.1% in men and 13.0% in women (p = 0.7).
  • The authors reported no survival differences between men and women who received neither surgery nor radiotherapy. They wrote that women showed longer survival at one and five years, particularly with surgery, with or without radiotherapy. In Table 2, five-year survival with surgery was 11.4% in men and 30.7% in women.
  • Mesothelioma incidence in women was about 0.4 cases per 100,000 people and did not change substantially over time. In men it has been stable at 1.8 per 100,000 for the past 10 years, after a peak of 2.5 per 100,000 in the early 1990s.
• The authors' conclusion: The authors concluded that women with MPM survived significantly longer than men in this large population-based cohort, even after adjustment for confounders. They said differences in asbestos exposure, tumor biology and circulating hormones must be investigated to understand this survival advantage.
• Limitations the authors state:
  • The role of tumor type (histology) could not be fully assessed, because almost two-thirds of SEER cases are classified as mesothelioma not otherwise specified.
  • Some relevant clinical information is missing or not collected in SEER.
  • SEER has no data on chemotherapy, and its broad stage definitions may cause some misclassification of stage. The authors argued this should not differ by gender.
  • Regarding incidence, the SEER areas may not reflect places where women are exposed to asbestos.

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, Epidemiology, Hazard Ratio, confidence interval, Asbestos Exposure, Prognosis.

Related studies

• Low homozygous/high heterozygous deletion status by p16 FISH correlates with a better prognostic group than high homozygous deletion status in malignant pleural mesothelioma — M. Hamasaki, S. Matsumoto, et al. (2016)
• Characteristics of malignant pleural mesothelioma in women — A.S. Wolf, W.G. Richards, et al. (2010)
• Phase II study of first-line bortezomib and cisplatin in malignant pleural mesothelioma and prospective validation of progression free survival rate as a primary end-point for mesothelioma clinical trials (European Organisation for Research and Treatment of Cancer 08052) — M.E. O'Brien, R.M. Gaafar, et al. (2013)
• 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)
• Differences in cancer survival by sex: a population-based study using cancer registry data — N. Afshar, D.R. English, et al. (2018)
• Loss of heterozygosity of chromosome 3p21 is associated with mutant TP53 and better patient survival in non-small-cell lung cancer — C.J. Marsit, M. Hasegawa, et al. (2004)

Browse more research in The Annals of Thoracic Surgery, or return to medical research.