# Prague C and M criteria (Barrett's oesophagus)

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

## TL;DR

The Prague C and M numbers on an endoscopy report give the length of Barrett's oesophagus in centimetres: C for the part that goes all the way round, M for the longest tongue.

## Summary

Barrett's oesophagus is a precancerous change for oesophageal adenocarcinoma. An international working group (Sharma and colleagues, Gastroenterology 2006) set criteria for recognising it at endoscopy and grading its extent as the circumferential (C) and maximum (M) length above the gastro-oesophageal junction. Scored on video recordings by 29 endoscopists, reliability was 0.95 for C and 0.94 for M; 97% and 95% of paired readings agreed within 2 cm.

## Fields

- Kind: Term
- Last checked: 2026-11-04
- Also known as: Prague C&M; Prague C and M criteria; Prague classification

## Sources

- Sharma et al., The development and validation of an endoscopic grading system for Barrett's esophagus: the Prague C & M criteria (Gastroenterology 2006): https://doi.org/10.1053/j.gastro.2006.08.032

## Connected records

- terms: [Barrett's oesophagus](https://onco.cc/terms/barretts-esophagus/), [Endoscopy (EGD, EUS, ERCP)](https://onco.cc/terms/endoscopy/), [Vienna classification of gastrointestinal epithelial neoplasia](https://onco.cc/terms/vienna-classification/)
- cancers: [Oesophageal and junctional adenocarcinoma](https://onco.cc/cancers/oesophageal-adenocarcinoma/)

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