# Peritoneal mesothelioma

Source: https://onco.cc/cancers/peritoneal-mesothelioma/  
OnCo record `peritoneal-mesothelioma` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Peritoneal mesothelioma grows in the lining of the abdomen, causing swelling, pain and fluid. Unlike its pleural cousin it is often treated with major surgery to strip the lining followed by heated chemotherapy washed through the abdomen, which can give long survival in fit patients with epithelioid disease.

## Summary

Peritoneal mesothelioma presents with abdominal distension from ascites, pain, weight loss or a mass found at surgery, and is diagnosed by laparoscopic biopsy with the same immunohistochemistry as pleural disease. Asbestos exposure is found in only a minority; BAP1 germline mutations account for some cases, and the disease is commoner in women than pleural mesothelioma. For fit patients with epithelioid histology and disease that can be removed, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) is the standard in specialist centres and gives median survival of five years or more in series, though no randomised trial exists. Patients who are not candidates receive platinum-pemetrexed chemotherapy, with immunotherapy increasingly used on the basis of small trials and the pleural data. Well-differentiated papillary and multicystic forms behave almost benignly and are managed separately.

## Fields

- Kind: Cancer
- Last checked: 2026-09-16
- Also known as: Malignant peritoneal mesothelioma; MPeM; Diffuse malignant peritoneal mesothelioma
- Tags: subtype-page
- Group: gastrointestinal
- Burden: About one in ten mesotheliomas; a few hundred cases a year in the US. The asbestos link is weaker than in the pleura, it affects more women and younger people, and selected patients live many years after surgery.
- Subtypes: Epithelioid (most cases); Biphasic and sarcomatoid (rare, shorter survival); Well-differentiated papillary mesothelial tumour (indolent); Multicystic mesothelioma (indolent)
- Biomarkers: Histology and peritoneal cancer index at laparoscopy; BAP1 loss (somatic and germline); Ki-67 (prognostic after surgery); Completeness of cytoreduction score

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/peritoneal-mesothelioma/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/peritoneal-mesothelioma/#overview [3 state-of-the-art points]
- Types and stages (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/peritoneal-mesothelioma/#what-it-is [4 subtypes]
- Symptoms and diagnosis (on the hub): How this cancer shows itself, how the diagnosis is confirmed, and the biomarkers clinicians test for. https://onco.cc/cancers/peritoneal-mesothelioma/#finding-it [4 biomarkers]
- Treatment (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/peritoneal-mesothelioma/#treating-it [4 settings, 1 decision with options]
- Trials and papers (on the hub): Trials recruiting now, the landmark trials, the trials held by this cancer's subtypes, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/peritoneal-mesothelioma/#evidence [2 trials, 4 key papers, 4 milestones]
- Biology and targets (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/peritoneal-mesothelioma/#science [2 targets]
- Countries and centres (own page): Cases by country, the UK and NHS pathway and other country lenses, the expert centres with trials on record, and the centres named on this cancer's subtypes. https://onco.cc/cancers/peritoneal-mesothelioma/where-you-are/
- Decisions and support (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/peritoneal-mesothelioma/#living-with-it [14 questions, 6 red cards]
- Pipeline and open problems (own page): Everything in development, the medicines held by this cancer's subtypes, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/peritoneal-mesothelioma/coming/ [4 medicines, 2 trials, 1 idea, 3 open problems]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/peritoneal-mesothelioma/data/ [25 connected records]

## Standard of care

- Diagnosis: CT, laparoscopy with biopsy and scoring of disease extent; germline BAP1 testing when young or with a family history. ([Mesothelioma](https://onco.cc/cancers/mesothelioma/))
- Resectable epithelioid disease, fit patient: Cytoreductive surgery with HIPEC in an experienced centre; long-term survival in a substantial fraction. ([HIPEC / PIPAC (intraperitoneal chemotherapy)](https://onco.cc/technologies/hipec/))
- Unresectable or unfit: Platinum-pemetrexed chemotherapy; nivolumab plus ipilimumab or pembrolizumab combinations extrapolated from pleural trials and small peritoneal series. ([Pemetrexed](https://onco.cc/drugs/pemetrexed/), [Nivolumab](https://onco.cc/drugs/nivolumab/), [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/))
- Indolent variants: Well-differentiated papillary and multicystic tumours: surgical removal and surveillance; systemic therapy rarely needed. ([Active surveillance](https://onco.cc/technologies/active-surveillance/))

## State of the art

- Cytoreduction with HIPEC, pioneered by Sugarbaker, turned a disease with a median survival under a year into one where a substantial fraction of selected patients live five years or more.
- Immunotherapy is being adopted from pleural mesothelioma with encouraging early results, and peritoneal patients are now included in mesothelin-directed trials.
- Registries and consortia have replaced case series as the evidence base because randomised trials are so hard to run in a disease this rare.

## Open problems

- No randomised trial has compared surgery plus HIPEC with systemic therapy.
- Selection for surgery relies on centre experience rather than validated criteria.
- Peritoneal patients were excluded from the pleural immunotherapy trials, so their benefit is inferred.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Peritoneal_mesothelioma
- Wikipedia: https://en.wikipedia.org/wiki/Peritoneal_mesothelioma

## Connected records

- cancers: [Desmoplastic small round cell tumour](https://onco.cc/cancers/desmoplastic-small-round-cell-tumour/), [Low-grade appendiceal mucinous neoplasm and pseudomyxoma peritonei](https://onco.cc/cancers/low-grade-appendiceal-mucinous-neoplasm/), [Mesothelioma](https://onco.cc/cancers/mesothelioma/), [Pleural mesothelioma](https://onco.cc/cancers/pleural-mesothelioma/)
- terms: [BAP1 loss](https://onco.cc/terms/bap1-loss/), [CDKN2A/B homozygous deletion](https://onco.cc/terms/cdkn2a-homozygous-deletion/), [Cytoreductive surgery](https://onco.cc/terms/cytoreductive-surgery/), [Peritoneal cancer index](https://onco.cc/terms/peritoneal-carcinomatosis-index/)
- key papers: [Atezolizumab plus bevacizumab in advanced malignant peritoneal mesothelioma](https://onco.cc/key-papers/paper-raghav-atezolizumab-bevacizumab-peritoneal-mesothelioma-cancer-discov-2021/), [CheckMate 743: first-line nivolumab plus ipilimumab in unresectable pleural mesothelioma](https://onco.cc/key-papers/paper-checkmate-743-lancet-2021/), [Cytoreductive surgery and HIPEC for malignant peritoneal mesothelioma: multi-institutional registry](https://onco.cc/key-papers/paper-yan-peritoneal-mesothelioma-crs-hipec-jco-2009/), [Phase 3 trial of pemetrexed plus cisplatin versus cisplatin alone in malignant pleural mesothelioma](https://onco.cc/key-papers/paper-vogelzang-pemetrexed-mesothelioma-jco-2003/)
- technologies: [Active surveillance](https://onco.cc/technologies/active-surveillance/), [HIPEC / PIPAC (intraperitoneal chemotherapy)](https://onco.cc/technologies/hipec/), [HIPEC perfusion pumps and PIPAC nebulisers](https://onco.cc/technologies/hipec-pipac-devices/)
- ideas: [Antibody-drug conjugates for mesothelioma: why they have failed so far and how they could work](https://onco.cc/ideas/idea-adc-for-mesothelioma/)
- drugs: [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Nivolumab](https://onco.cc/drugs/nivolumab/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [Pemetrexed](https://onco.cc/drugs/pemetrexed/)
- trials: [Dual-Target MSLN/FAP CAR-NK Cells for Pleural and Peritoneal Mesothelioma](https://onco.cc/trials/nct07510815/), [Randomized, Double-blind Study Comparing Tremelimumab to Placebo in Subjects With Unresectable Malignant Mesothelioma](https://onco.cc/trials/nct01843374/)

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JSON: https://onco.cc/api/v1/entities/peritoneal-mesothelioma.json