Brain metastases in malignant pleural mesothelioma

Our plain-English summary of Brain metastases in malignant pleural mesothelioma, by T. Yamagishi, N. Fujimoto, Y. Miyamoto, et al (Clinical & Experimental Metastasis, 2016).

The study

• Authors: T. Yamagishi, N. Fujimoto, Y. Miyamoto, M. Asano, Y. Fuchimoto, S. Wada, K. Kitamura, S. Ozaki, H. Nishi, T. Kishimoto
• Journal: Clinical & Experimental Metastasis
• Published: 2016;33(3):231-7
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The brain is a rare site of metastasis in malignant pleural mesothelioma (MPM), and its clinical features and prognosis remain unclear. The aim of this study was to investigate the incidence, prognosis, and risk factors for brain metastases (BM) in MPM patients. Between July 1993 and October 2014, 150 patients with histologically proven MPM were included in this retrospective study. The cumulative incidence of BM was estimated with the Kaplan-Meier method, and differences between groups were analyzed by the log-rank test. Multivariate logistic regression analysis was applied to assess risk factors for BM. The median follow-up time was 11 months (range 0-154.0 months). A total of eight patients (5.3 %) developed BM during the course of their illness. Multivariate analysis identified age <65 years (odds ratio [OR] = 5.83, p = 0.038) and International Mesothelioma Interest Group stage IV (OR = 1.69, p = 0.040) as independent factors related to increased risk of developing BM. The 1-and 2-year cumulative rates of BM were 4.0 % (95 % confidence intervals [CI] 1.4-8.5 %) and 5.3 % (95 % CI 2.3-10.2 %), respectively. Our study showed that the overall survival (OS) of patients with BM was worse than that of patients without BM (median OS 6.5 vs. 11.0 months, p = 0.037). The prognosis for BM in MPM patients is poor. Clinicians should perform careful screening for BM, especially in patients with risk factors.

In plain English

This retrospective study from one Japanese hospital examined how often malignant pleural mesothelioma spread to the brain, what was linked to it, and survival. It included 150 consecutive patients seen at Okayama Rosai Hospital from July 1993 to October 2014. Eight developed brain metastases: three at diagnosis and five later. The 1- and 2-year cumulative rates were 4.0% (95% CI 1.4 to 8.5%) and 5.3% (95% CI 2.3 to 10.2%). Median overall survival was 6.5 months with brain metastases and 11.0 months without (p = 0.037). In the multivariate analysis, two factors were associated with higher risk. One was age under 65 compared with 65 or older (odds ratio 5.83, 95% CI 1.10 to 30.73). The other was International Mesothelioma Interest Group stage IV compared with stages I to III (odds ratio 1.69, 95% CI 1.02 to 2.80). Histological subtype was not significantly associated. The authors concluded that the prognosis was poor and that clinicians should screen carefully, especially patients with these risk factors. They noted the small study size. They also noted that metastases without symptoms may have been missed, because brain scans after diagnosis were done only when suspected. Asbestos exposure was not reported.

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 (review of patients' medical records)
• Who was studied: 150 consecutive patients with histologically proven malignant pleural mesothelioma seen at Okayama Rosai Hospital, Japan, between July 1993 and October 2014. Median follow-up was 11.0 months (range 0 to 154.0 months).
• Exposure: Not studied. The study examined brain metastases in mesothelioma patients and did not report the patients' asbestos exposure. Asbestos is mentioned only in the introduction as associated with the disease.
• Main results:
  • Of 150 patients, 8 developed brain metastases: 3 at diagnosis of mesothelioma and 5 during the course of the illness.
  • The 1-year cumulative rate of brain metastases was 4.0% (95% CI 1.4 to 8.5%). The 2-year rate was 5.3% (95% CI 2.3 to 10.2%).
  • All 8 patients with brain metastases were men. Three had stage III disease and 5 had stage IV disease. Four of the 8 (50%) had symptoms of brain metastases.
  • Median overall survival was 11.0 months (range 0 to 154.0) in patients without brain metastases and 6.5 months (range 2.0 to 27.0) in patients with brain metastases (p = 0.037).
  • All patients with brain metastases died of progressive disease. Their median survival after the brain metastases developed was 3.5 months (range 1.0 to 5.0 months).
  • In the multivariate analysis, age under 65 years, compared with age 65 or older, was associated with a higher risk of brain metastases (odds ratio 5.83, 95% CI 1.10 to 30.73, p = 0.038).
  • In the multivariate analysis, International Mesothelioma Interest Group stage IV, compared with stages I to III, was associated with a higher risk of brain metastases (odds ratio 1.69, 95% CI 1.02 to 2.80, p = 0.040).
  • In the univariate analysis, nonepithelioid histology was not significantly associated with brain metastases compared with epithelioid histology (odds ratio 1.10, 95% CI 0.25 to 4.81, p = 0.895).
  • Cumulative incidence of brain metastases by risk-factor group: 0% for patients aged 65 or older with stage I to III; 8.1% for those under 65 with stage I to III; 8.3% for those aged 65 or older with stage IV; 18.7% for those under 65 with stage IV (p = 0.003, Fisher's exact test).
• The authors' conclusion: The authors concluded that the prognosis for mesothelioma patients with brain metastases is poor and that clinicians should screen carefully for brain metastases, especially in patients with risk factors. They suggested it may be reasonable to perform brain imaging in patients under 65 or with stage IV disease, even without neurological symptoms.
• Limitations the authors state:
  • Retrospective study at a single institution.
  • The small number of patients and events limited the statistical analysis.
  • Brain metastases without symptoms may have been missed. The authors linked this to detection based on patients' symptoms. The methods state that routine brain imaging was done at diagnosis but not during follow-up unless brain metastases were suspected.

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, Metastasis, Prognosis, Multivariate Analysis, Odds Ratio, Mesothelioma, confidence interval, Overall Survival.

Related studies

• Malignant mesothelioma with brain metastases — J.A. Kaye, A.M. Wang, et al. (1986)
• Brain metastases in malignant pleural mesothelioma. Case report and review of the literature — K.S. Sridhar, A.M. Hussein, et al. (1989)
• Response to chemotherapy of brain metastases from malignant pleural mesothelioma — M. Colleoni, G. Liessi, et al. (1996)
• Meningeal and brain metastases in primary malignant pericardial mesothelioma — U. Bohn, J.L. Gonzalez, et al. (1994)
• Prognostic significance of the lymphocyte-to-monocyte ratio in patients with malignant pleural mesothelioma — T. Yamagishi, N. Fujimoto, et al. (2015)
• Simian virus 40 transformation, malignant mesothelioma and brain tumors — F. Qi, M. Carbone, et al. (2011)

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