Malignant peritoneal mesothelioma: a review

Our plain-English summary of Malignant peritoneal mesothelioma: a review, by G. Broeckx, P. Pauwels (Translational Lung Cancer Research, 2018).

The study

• Authors: G. Broeckx, P. Pauwels
• Journal: Translational Lung Cancer Research
• Published: 2018;7(5):537-542
• Type of article: Review
• Cited by: 78 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Malignant peritoneal mesothelioma (MPM) is a very rare malignancy of the peritoneum and has a poor prognosis. Of all mesotheliomas, pleural mesothelioma is more common than MPM. In comparison to pleural mesothelioma, the link with asbestos exposure is weaker (33-50% vs. >80%), but it is still the best-defined risk factor. MPM spreads predominantly expansive rather than infiltrative and symptoms are related to tumor spread within the abdominal cavity. Often, MPM is encountered incidentally by diagnostic imaging or by surgery. Computed tomography scan is widely accepted as a first line modality in diagnostic imaging. In diagnostic histopathology, MPM presents some challenges. Firstly, adequate clinical information is of utmost importance to consider the possibility of the diagnosis of MPM. Furthermore, a few morphological subtypes and variants exist. The most sensitive immunohistochemical markers are calretinin (100%), WT1 (94%) and CK5/6 (89%). The malignant character of immunohistochemically demonstrated mesothelial cells is not always obvious. This paradigm somewhat changed with the advent of immunohistochemical demonstration of BAP1 (BRCA-1 associated protein 1). Loss of BAP1 expression supports a diagnosis of malignancy. The gold standard in treatment remains cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Targetable molecular pathways in MPM are being identified. An exciting finding was the demonstration of ALK rearrangements in a small subset of patients with MPM and it is hoped for that at least this small subgroup of patients could benefit from treatment with ALK inhibitors. First-generation tyrosine kinase inhibitors against epidermal growth factor receptor (EGFR) did not show any significant activity in MPM. In contrast, nintedanib, an angiokinase inhibitor, improved progression-free survival and bevacizumab, a humanized anti-VEGF antibody increased overall survival in patients with MPM, when administered in combination with cisplatin and pemetrexed. Ongoing immunotherapy trials will offer a possible new treatment.

In plain English

This article was a narrative review of malignant peritoneal mesothelioma, a rare cancer of the lining of the abdomen, by two authors from the Department of Pathology at the University Hospital of Antwerp, Belgium. It summarized earlier published work and did not report new patient data. Citing other sources, it stated that 10–30% of mesothelioma cases arise in the peritoneum. It said the link with asbestos is weaker than for pleural mesothelioma (33–50% versus more than 80%), but asbestos is still the best-defined risk factor. It gave a latency between asbestos exposure and disease of 20 years, compared with 30–40 years for pleural mesothelioma. The review also covered symptoms, CT imaging, tissue markers including BAP1, staging, and treatment. It cited reports that, in selected patients, surgery to remove the tumor combined with heated chemotherapy inside the abdomen (HIPEC) extended median survival from 6 months in untreated patients to 34–92 months for those who had this treatment. The authors concluded that diagnosis remains challenging and that this combined treatment remains the gold standard.

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: Narrative review of published literature (no new data collected)
• Who was studied: No study population of its own. The review drew on published studies of patients with malignant peritoneal mesothelioma.
• Exposure: Asbestos exposure in general, discussed as a risk factor. No specific fiber types, products or jobs are named.
• Main results:
  • Citing an earlier source, the review stated that 10–30% of all mesothelioma cases originate from the peritoneum.
  • Citing an earlier review, the authors stated that the link with asbestos exposure is weaker in peritoneal than in pleural mesothelioma (33–50% vs. more than 80%), but asbestos is still the best-defined risk factor.
  • The review reported a shorter latency period between asbestos exposure and mesothelioma for the peritoneal form (20 years) than for pleural mesothelioma (30–40 years).
  • The review reported a lower median age at diagnosis for peritoneal than for pleural mesothelioma (63 vs. 71 years). Peritoneal mesothelioma was described as more frequent in females, and pleural as more frequent in males.
  • In a study by Tandon et al. of 244 peritoneal mesothelioma cases, the most sensitive tissue markers were calretinin (100%), WT1 (94%) and CK5/6 (89%). D2-40 was positive in 80% of cases.
  • Citing other studies, the review stated that in select patients, cytoreductive surgery with HIPEC extended overall survival from a median of 6 months in untreated patients to 34–92 months.
  • A meta-analysis of 20 studies (1,047 patients treated with CRS-HIPEC) showed 5-year survival of 42% among the 67% of patients who achieved complete or near complete cytoreduction.
  • Citing another study, the review reported ALK rearrangements in 3% of patients with peritoneal mesothelioma and in none with pleural mesothelioma. No asbestos fibers could be detected in the ALK-rearranged cases.
• The authors' conclusion: The authors concluded that malignant peritoneal mesothelioma is a very rare cancer with poor prognosis and remains challenging to diagnose. In their view, BAP1 staining helps distinguish benign mesothelial hyperplasia from the cancer, and cytoreductive surgery combined with HIPEC remains the gold standard treatment.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Peritoneum, Prognosis, Mesothelioma, Pleural Mesothelioma, Asbestos Exposure, Histopathology, Calretinin.

Related studies

• Peritoneal mesothelioma — M. Kannerstein, J. Churg (1977)
• Intraperitoneal chemotherapy for peritoneal surface malignancy: experience with 1,000 patients — E.A. Levine, J.H. Stewart, et al. (2014)
• Epidemiology of peritoneal mesothelioma: a review — P. Boffetta (2007)
• Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for malignant peritoneal mesothelioma: a systematic review and meta-analysis — J.H. Helm, J.T. Miura, et al. (2015)
• Absence of carcinogenic response to multiwall carbon nanotubes in a 2-year bioassay in the peritoneal cavity of the rat — J. Muller, M. Delos, et al. (2009)
• Papillary peritoneal tumors in women — A. Foyle, M. Al-Jabi, et al. (1981)

Browse more research in Translational Lung Cancer Research, or return to medical research.