Gastric Cancer — TNM

AJCC 8th edition (2017), pathological (pTNM) — gastric adenocarcinoma

T — primary tumour

Tis — carcinoma in situ / high-grade dysplasia

T1 — invades the lamina propria, muscularis mucosae or submucosa

T2 — invades the muscularis propria

T3 — penetrates the subserosal connective tissue

T4a — invades the serosa (visceral peritoneum)

T4b — invades adjacent structures or organs

N — regional lymph nodes

N0 — no regional lymph node metastasis

N1 — metastasis in 1–2 regional lymph nodes

N2 — metastasis in 3–6 regional lymph nodes

N3a — metastasis in 7–15 regional lymph nodes

N3b — metastasis in ≥ 16 regional lymph nodes

M — distant metastasis

M0 — no distant metastasis

M1 — distant metastasis (includes positive peritoneal cytology)

Evidence

Original publication

In H, Solsky I, Palis B, et al. Validation of the 8th edition of the AJCC TNM staging system for gastric cancer using the National Cancer Database. Confirmed that the 8th-edition pathological stage groups discriminate survival, with the largest changes affecting node-positive disease.

Annals of Surgical Oncology, 2017

Open source

Guideline

Amin MB, Edge SB, Greene FL, et al., eds. AJCC Cancer Staging Manual, 8th edition. Chicago: Springer; 2017. This tool uses the pathological (pTNM) table; separate clinical and post-neoadjuvant (yp) tables exist. Confirm against the manual.

Last reviewed: 2026-09

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