# Peritoneum and peritoneal metastases

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

## TL;DR

The thin membrane lining the abdominal cavity and covering the bowel. Cancers of the ovary, stomach, colon, appendix and pancreas seed it with small, poorly vascularised deposits that CT under-detects and drugs reach badly, which is why surgery with heated intraperitoneal chemotherapy (HIPEC) is used in appendiceal and selected ovarian cancers.

## Summary

Peritoneal metastases (carcinomatosis) cause ascites, bowel obstruction and cachexia, are under-detected by CT, and respond poorly to systemic therapy because deposits are small, poorly vascularised and bathed in a protective fluid space. Treatments include cytoreductive surgery with HIPEC (standard in appendiceal and selected ovarian cancers), intraperitoneal chemotherapy and PIPAC, and in gastric cancer the extent of peritoneal disease (P score, cytology) determines resectability. Mesothelioma can also arise from the peritoneum.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: peritoneal; peritoneal metastases; peritoneal carcinomatosis; carcinomatosis; peritoneal disease; peritoneal spread; peritoneal cavity; omentum; omental

## Sources

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

## Connected records

- terms: [Debulking (cytoreductive surgery)](https://onco.cc/terms/debulking/), [HIPEC (hyperthermic intraperitoneal chemotherapy)](https://onco.cc/terms/hipec-procedure/), [Intraperitoneal (IP) chemotherapy](https://onco.cc/terms/intraperitoneal-chemotherapy/), [Laparoscopy (keyhole surgery)](https://onco.cc/terms/staging-laparoscopy/), [Malignant pleural effusion and ascites](https://onco.cc/terms/pleural-effusion/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [Low-grade appendiceal mucinous neoplasm and pseudomyxoma peritonei](https://onco.cc/cancers/low-grade-appendiceal-mucinous-neoplasm/), [Mesothelioma](https://onco.cc/cancers/mesothelioma/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/)
- fronts: [Surgery & Interventional](https://onco.cc/fronts/surgery/)

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JSON: https://onco.cc/api/v1/entities/peritoneum.json