Postmortem findings of malignant pleural mesothelioma: a two-center study of 318 patients

Our plain-English summary of Postmortem findings of malignant pleural mesothelioma: a two-center study of 318 patients, by R.S. Finn, F.J.H. Brims, A. Gandhi, et al (Chest, 2012).

The study

• Authors: R.S. Finn, F.J.H. Brims, A. Gandhi, N. Olsen, A.W. Musk, N.A. Maskell, Y.C.G. Lee
• Journal: Chest
• Published: 2012;142(5):1267-1273
• Cited by: 92 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Malignant pleural mesothelioma (MPM) is an incurable cancer with a rising incidence. MPM is often perceived as a locally invasive cancer, and the exact cause of death is poorly understood.This two-center study describes the anatomic features of patients with MPM at postmortem.

Methods: The Western Australia Mesothelioma Registry (Australia) and Coroner’s Office reports from the Avon region (England) were interrogated for the postmortem records of confirmed mesothelioma cases.

Results: Postmortem records of 318 patients with pleural mesothelioma (169 from Western Australia and 149 from Avon) were identified. Most patients (91.5%) were men (mean age, 68.4 ± 11.5 years), and MPM was right-sided in 55.3%. Extrapleural dissemination of tumor was found in 87.7% of cases and lymph node involvement in 53.3%. Tumor dissemination in extra thoracicsites was common (55.4% of patients), and almost all organs were involved, including liver(31.9%), spleen (10.8%), thyroid (6.9%), and the brain (3.0%). Pulmonary emboli were found in 6% of cases and considered as directly contributing to death in 13 patients (4.1%). The precise cause of death could only be determined in 63 (19.8%) cases even after postmortem. The BMI was significantly lower in cases that had no identifiable anatomic cause of death at postmortem(18.8 ± 4.3 vs 21.0 ± 4.7, P = .034).

Conclusions: In this largest, to our knowledge, postmortem series on MPM, extrathoracic dissemination of mesothelioma was common and often under recognized. No anatomic cause of death was identified in the majority of patients even at autopsy, raising the possibility of physiologic and metabolic causes of death.

In plain English

The authors reviewed autopsy records of 318 people with malignant pleural mesothelioma: 169 from the Western Australia Mesothelioma Registry (1969 to May 2009) and 149 from coroner's records in Avon, England (2005 to 2008). They described exposure as mainly crocidolite in Western Australia and mainly chrysotile in Avon. They stated they could not examine whether fiber type explained group differences. Cancer had spread beyond the pleura on the side where it began in 278 patients (87.7%), to lymph nodes in 169 (53.3%), and to organs outside the chest in 165 (55.4%). These percentages were not out of all 318: the article did not say how many patients each was based on, and 19 autopsies examined only the chest. A definite cause of death was established in only 63 cases (19.8%). The authors concluded this raised the possibility of physiologic and metabolic causes of death. Pulmonary emboli (blood clots in the lungs) were considered to have contributed to death in 13 patients (4.1%). Body mass index was lower in patients with no identifiable anatomic cause of death (18.8 vs 21.0). They noted spread was likely underestimated.

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 observational review of postmortem (autopsy) records from two regional centers
• Who was studied: 318 patients with primary pleural mesothelioma and a complete postmortem record. 169 came from the Western Australia Mesothelioma Registry (searched from its establishment in 1969 to May 2009) and 149 from Coroner's Office records in the Avon area, England (deaths 2005 to 2008). 91.5% were men. 26 patients with primary peritoneal mesothelioma were excluded. In 19 Western Australia patients the postmortem examination covered only the chest.
• Exposure: Exposure was not measured in this study. The authors described the Western Australia cohort as exposed mainly to crocidolite and the Avon cohort as exposed predominantly to chrysotile imported for industrial use.
• Main results:
  • Mesothelioma had spread beyond the pleura on the side where it began in 278 patients (87.7%), as reported for the combined cohort. 278 out of 318 would be 87.4%, so the printed percentage rests on a slightly smaller, unstated number of patients.
  • Lymph node involvement was found in 169 patients (53.3%). The number of patients this percentage is based on was not stated; it is not 318.
  • Mesothelioma was found in organs outside the chest in 165 patients (55.4%). This percentage is not out of all 318 (165 of 318 would be 51.9%). The article does not state the number used, and 19 postmortems were limited to the chest. The most frequent sites were the liver (31.9%), peritoneum (24.4%) and bone (13.8%).
  • Nineteen postmortem examinations, all in the Western Australia cohort, were limited to the chest.
  • A precise cause of death could be determined in only 63 cases (19.8%), even after postmortem.
  • Pneumonia was recorded in 82 cases but was considered the cause of death in 54 (16.9%).
  • Pulmonary emboli were reported in 20 patients (6.3%) and were considered to have contributed to death in 13 (4.1%).
  • Cardiac tamponade contributed to death in six patients (1.9%).
  • BMI was lower in patients with no anatomic cause of death identified than in those with an apparent cause: mean 18.8 (SD 4.3) vs 21.0 (SD 4.7), P = .034. In the combined cohort, 25% of patients were cachectic, with a BMI below 17.
  • Lymph node involvement differed by tumor type. Table 4 gives 63 (67.0%) for epithelioid, 49 (65.3%) for biphasic and 21 (38.2%) for sarcomatoid tumors. Rates of any extrapleural spread showed no statistically significant difference between tumor types.
• The authors' conclusion: The authors concluded that extrathoracic spread of mesothelioma was common. Because no anatomic cause of death was identified in most patients even at autopsy, they raised the possibility of physiologic and metabolic causes of death.
• Limitations the authors state:
  • The true rate of spread beyond the pleura is likely underestimated in a retrospective series, because postmortem techniques and tissue sampling were not standardized.
  • Postmortem series cannot show when during the disease course findings such as distant spread developed.
  • Results from two regional centers were combined. The higher rate of spread in Western Australia may reflect local postmortem practice, and whether it relates to asbestos type could not be examined.

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, Mesothelioma, Autopsy.

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