# Early gastric cancer

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

## TL;DR

Early gastric cancer has not grown beyond the submucosa, whatever the lymph nodes show. In Japan and Korea, where screening endoscopy finds most stomach cancers at this stage, many are removed through the endoscope without an operation, and the rest are cured by gastrectomy.

## Summary

Early gastric cancer is defined by depth: a tumour limited to the mucosa (T1a) or submucosa (T1b), regardless of nodal spread. Its detection depends on endoscopy in people without symptoms. Korea has offered biennial endoscopic screening to everyone from age 40 in its national programme since 1999, and Japan recommended endoscopy over barium radiography in 2016; as a result more than half of gastric cancers in both countries are early, against about one in five in Europe and North America. Helicobacter pylori causes most of these cancers, and eradication after endoscopic resection roughly halves the risk of a second primary tumour in the remaining stomach.

Endoscopic submucosal dissection removes the lesion in one piece with its margins. The Japanese Gastric Cancer Association criteria cover differentiated intramucosal tumours without ulceration of any size, differentiated ulcerated tumours up to 3 cm, and, after the JCOG1009/1010 trial, undifferentiated intramucosal tumours up to 2 cm without ulceration; when pathology shows deeper invasion, lymphovascular invasion or an involved margin (a high eCura risk), gastrectomy with lymph node dissection follows because the risk of nodal disease rises. Curative dissection preserves the stomach and its function with recurrence rates comparable to surgery in matched series.

For tumours outside those criteria, gastrectomy with D1+ node dissection is standard; laparoscopic distal gastrectomy proved non-inferior to open surgery for stage I disease in the Korean KLASS-01 and Japanese JCOG0912 trials and is now routine, with robotic surgery an alternative. Adjuvant chemotherapy is not given for stage I disease. Surveillance after endoscopic resection is annual endoscopy for metachronous lesions, and the whole model is being tested in Western trials of risk-based screening and in the gastric cancer arm of Lynch syndrome programmes.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: T1 gastric cancer; Intramucosal gastric cancer; Submucosal gastric cancer; Screen-detected gastric cancer
- Tags: subtype-page
- Group: gastrointestinal
- Burden: More than half of gastric cancers diagnosed in Japan and Korea, where endoscopic screening finds them, but a small minority in Western countries; five-year survival above 90 percent when the tumour is confined to the mucosa or submucosa.
- Subtypes: Intramucosal (T1a) differentiated early gastric cancer (endoscopic resection); Undifferentiated intramucosal cancer up to 2 cm (endoscopic resection after JCOG1009/1010); Submucosal (T1b) early gastric cancer (gastrectomy); Distal (antral) early gastric cancer, intestinal type; Screen-detected early gastric cancer (Japan and Korea); Metachronous early gastric cancer after resection
- Biomarkers: Depth of invasion, ulceration and size (endoscopic resection criteria); Differentiated versus undifferentiated histology; Lymphovascular invasion and margin status on the resected specimen (eCura risk); Helicobacter pylori status; Intestinal metaplasia and atrophy extent (Kimura-Takemoto, OLGA) for surveillance intervals

## 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/early-gastric-cancer/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/early-gastric-cancer/#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/early-gastric-cancer/#what-it-is [6 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/early-gastric-cancer/#finding-it [5 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/early-gastric-cancer/#treating-it [4 settings]
- 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/early-gastric-cancer/#evidence [2 trials, 4 key papers, 6 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/early-gastric-cancer/#science
- 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/early-gastric-cancer/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/early-gastric-cancer/#living-with-it [13 questions]
- 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/early-gastric-cancer/coming/ [2 trials, 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/early-gastric-cancer/data/ [19 connected records]

## Standard of care

- Within endoscopic criteria: Endoscopic submucosal dissection with en bloc resection and pathological assessment of depth, margins and lymphovascular invasion. ([Endoscopic resection (EMR / ESD)](https://onco.cc/technologies/endoscopic-resection/), [Endoscopy (EGD, EUS, ERCP)](https://onco.cc/terms/endoscopy/))
- Non-curative resection or outside criteria: Gastrectomy with D1+ lymph node dissection, laparoscopic or robotic (KLASS-01, JCOG0912). ([Gastrectomy](https://onco.cc/terms/gastrectomy/), [Lymphadenectomy (lymph node dissection)](https://onco.cc/terms/lymphadenectomy/), [Robotic & minimally invasive surgery](https://onco.cc/technologies/robotic-surgery/), [Japan Clinical Oncology Group (JCOG)](https://onco.cc/companies/jcog/))
- After resection: Helicobacter pylori eradication and annual endoscopic surveillance for metachronous cancer; no adjuvant chemotherapy for stage I. ([Endoscopy (EGD, EUS, ERCP)](https://onco.cc/terms/endoscopy/), [Chemoprevention & risk-reducing surgery](https://onco.cc/technologies/chemoprevention/))
- Screening: Biennial endoscopy from age 40 in Korea and from 50 in Japan; risk-based screening for people of East Asian origin and with atrophic gastritis elsewhere. ([Screening](https://onco.cc/terms/screening/), [Endoscopy (EGD, EUS, ERCP)](https://onco.cc/terms/endoscopy/))

## State of the art

- Endoscopic submucosal dissection, developed in Japan, cures the majority of early gastric cancers without removing the stomach.
- Population endoscopic screening has made early-stage diagnosis the norm in Korea and Japan and is the reason their survival figures lead the world.
- Helicobacter pylori eradication after resection is proven to prevent second cancers.

## Open problems

- Western countries have no screening and diagnose most gastric cancers late.
- Predicting nodal spread in submucosal tumours to spare more patients surgery.
- Artificial intelligence detection of subtle lesions is promising but not yet proven to change outcomes.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Stomach_cancer
- Japanese gastric cancer treatment guidelines 2021 (6th edition): https://pubmed.ncbi.nlm.nih.gov/36342574/
- JCOG1009/1010 (Gastric Cancer 2020): https://pubmed.ncbi.nlm.nih.gov/32895785/
- Wikipedia: https://en.wikipedia.org/wiki/Stomach_cancer

## Connected records

- cancers: [Claudin 18.2-positive gastric cancer](https://onco.cc/cancers/gastric-cldn18-2-positive/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [HER2-positive gastric cancer](https://onco.cc/cancers/gastric-her2-positive/), [Microsatellite-unstable (MSI-high) gastric cancer](https://onco.cc/cancers/gastric-msi-high/), [PD-L1-high gastric cancer](https://onco.cc/cancers/gastric-pdl1-high/)
- trials: [KLASS-01](https://onco.cc/trials/klass-01/), [Magnetic-controlled Capsule Endoscopy vs. Gastroscopy for Detection of Gastric Diseases](https://onco.cc/trials/nct02219529/)
- key papers: [Incidence of lymph node metastasis from early gastric cancer: estimation from 5,265 patients at two large centres](https://onco.cc/key-papers/paper-gotoda-endoscopic-resection-criteria-gastric-cancer-2000/), [Japanese gastric cancer treatment guidelines 2021 (6th edition)](https://onco.cc/key-papers/paper-japanese-gastric-cancer-treatment-guidelines-2021-gastric-cancer-2023/), [JCOG0912: laparoscopy-assisted versus open distal gastrectomy for clinical stage IA or IB gastric cancer](https://onco.cc/key-papers/paper-jcog0912-katai-lancet-gastroenterol-hepatol-2020/), [KLASS-01: laparoscopic versus open distal gastrectomy for stage I gastric cancer, long-term survival](https://onco.cc/key-papers/paper-klass-01-kim-jama-oncol-2019/)
- technologies: [Chemoprevention & risk-reducing surgery](https://onco.cc/technologies/chemoprevention/), [Endoscopic resection (EMR / ESD)](https://onco.cc/technologies/endoscopic-resection/), [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/), [Robotic & minimally invasive surgery](https://onco.cc/technologies/robotic-surgery/)
- companies: [Japan Clinical Oncology Group (JCOG)](https://onco.cc/companies/jcog/)
- terms: [Depth of invasion (DOI)](https://onco.cc/terms/depth-of-invasion/), [Endoscopy (EGD, EUS, ERCP)](https://onco.cc/terms/endoscopy/), [Gastrectomy](https://onco.cc/terms/gastrectomy/), [Lymphadenectomy (lymph node dissection)](https://onco.cc/terms/lymphadenectomy/), [Screening](https://onco.cc/terms/screening/)
- people: [Hitoshi Katai](https://onco.cc/people/hitoshi-katai/), [Hyung-Ho Kim](https://onco.cc/people/hyung-ho-kim/)

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JSON: https://onco.cc/api/v1/entities/early-gastric-cancer.json