Clinical Significance of Bone Metastases in Pleural Mesothelioma

Our plain-English summary of Clinical Significance of Bone Metastases in Pleural Mesothelioma, by M. Miyake, K. Kuribayashi, H. Doi, et al (Thoracic Cancer, 2025).

The study

• Authors: M. Miyake, K. Kuribayashi, H. Doi, A. Kubota, T. Otuski, Y. Negi, K. Mikami, R. Takahashi, A. Nakamura, Y. Nakajima, D. Fujimoto, K. Kitajima, T. Minami, T. Kijima
• Journal: Thoracic Cancer
• Published: 2025;16(5):e70033
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Bone metastasis (BoM) is common in advanced cancer, but its incidence in pleural mesothelioma (PM) remains unclear. This study aimed to determine the incidence of BoM in PM patients and assess its prognosis and risk factors to clarify its clinical significance.

Methods: A retrospective analysis was conducted on 515 histologically confirmed PM patients enrolled between January 2011 and December 2020. The cumulative incidence of BoM was calculated using the Kaplan-Meier method, with group differences assessed via log-rank tests. Risk factors for BoM were evaluated using multivariate logistic regression.

Results: The median follow-up was 13.3 months (range: 0.2-106.7 months). BoM was detected in 59 patients (11.5%) at diagnosis or during disease progression. Multivariate analysis identified non-epithelial histology (odds ratio [OR]: 2.189, 95% confidence interval [CI]: 1.179-4.065, p = 0.013) as an independent risk factor for developing BoM. Patients with BoM had worse overall survival (OS) compared to those without BoM (median OS: 18.6 months vs. 21.7 months, p = 0.03).

Conclusions: BoM in PM occurs less frequently than in primary lung cancer, with non-epithelial histology being more commonly associated with BoM. Patients with BoM had a poor prognosis, particularly when BoM was present at diagnosis. This study is limited by its retrospective design, which may introduce biases related to data collection and patient selection. Future prospective studies are needed to validate these findings.

© 2025 The Author(s). Thoracic Cancer published by John Wiley & Sons Australia, Ltd.

In plain English

This was a retrospective study from one hospital department in Japan (Hyogo Medical University) of 515 patients diagnosed with pleural mesothelioma between January 2011 and December 2020. It examined how often the cancer spread to bone and what that meant for survival. The study did not examine asbestos exposure. Bone spread (bone metastasis) was found in 59 patients: 14 at first diagnosis (2.7%) and 45 later, or 11.5% overall. Patients with bone spread had a median overall survival of 18.6 months, compared with 21.7 months for the 456 without it (p = 0.0294). Those with bone spread at diagnosis had a median survival of 4.0 months, against 22.0 months for those whose bone spread appeared later. In the multivariate analysis, non-epithelial histology was associated with bone spread (odds ratio 2.189, 95% CI 1.179 to 4.065). The authors concluded that the prognosis of these patients is poor. They noted that the study was small, single-center and retrospective. Most bone metastases were diagnosed by imaging, so some could be false positives.

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: Single-center retrospective study of patient medical records
• Who was studied: 515 patients with histologically diagnosed pleural mesothelioma (389 epithelial, 73 sarcoma, 42 biphasic, 11 desmoplastic types) seen between January 2011 and December 2020 at the Department of Respiratory Medicine and Hematology, Hyogo Medical University, Japan
• Exposure: Asbestos exposure was not studied; asbestos is mentioned only as background. The factor examined was bone metastasis, identified mainly by imaging (FDG-PET, X-ray, CT, MRI), not always confirmed by tissue biopsy.
• Main results:
  • Of 515 patients, 59 had bone metastasis: 14 at diagnosis and 45 during the course of disease. Crude incidence was 2.7% at diagnosis and 11.5% overall.
  • Median overall survival was 18.6 months in the 59 patients with bone metastasis and 21.7 months in the 456 without (p = 0.0294).
  • Median overall survival was 4.0 months in the 14 patients with bone metastasis at diagnosis and 22.0 months in the 45 whose bone metastasis appeared during the disease course (p less than 0.0001).
  • In the bone metastasis group, median survival after onset of bone metastasis was 4.03 months.
  • Non-epithelioid histology was more common in patients with bone metastasis than without (36% vs 23% per Table 2, p = 0.0346).
  • In multivariate analysis, non-epithelial histology was associated with bone metastasis (OR 2.189, 95% CI 1.179–4.065, p = 0.013, as given in the text).
  • Among patients with bone metastasis, survival did not differ between those with a single site (26) and multiple sites (33).
  • Skeletal-related events (such as fractures, spinal cord compression, or radiotherapy for bone lesions) occurred in 13 of the 59 patients with bone metastasis. The printed percentage, 2.52%, corresponds to 13 of all 515 patients.
• The authors' conclusion: The authors concluded that the prognosis of pleural mesothelioma patients with bone metastasis is poor and that bone metastasis severely affects quality of life and survival. They added that prognosis may differ depending on when bone metastasis first appears.
• Limitations the authors state:
  • Single-center retrospective design with relatively small numbers of patients and events, limiting statistical analysis
  • Most bone metastases were diagnosed by imaging, so false positives are possible
  • Follow-up was of medium length; longer follow-up is needed
  • Survivorship bias: patients who lived longer had more chance to develop bone metastasis
  • Possible underreporting of cases without symptoms (detection bias)
  • Skeletal-related events were likely underreported because of the retrospective design
  • Pain was assessed from patients' descriptions, without standardized measurement scales

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, Metastasis, Prognosis, Disease Progression, Multivariate Analysis, Histology, Odds Ratio, confidence interval.

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