TNM Classification for Gastric Cancer

The American Joint Committee on Cancer (AJCC) tumor/node/metastasis (TNM) classification and staging systems for gastric cancer are provided below.^[1]Post-neoadjuvant treatment staging classifications and overall survival data are also provided.^[2]

Table 1. TNM classification for gastric cancer (Open Table in a new window)

Primary tumor (T)
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in situ: intraepithelial tumor without invasion of the lamina propria
T1	Tumor invades lamina propria, muscularis mucosae, or submucosa
T1a	Tumor invades lamina propria or muscularis mucosae
T1b	Tumor invades submucosa
T2	Tumor invades muscularis propria
T3	Tumor penetrates subserosal connective tissue without invasion of visceral peritoneum or adjacent structures
T4	Tumor invades serosa (visceral peritoneum) or adjacent structures
T4a	Tumor invades serosa (visceral peritoneum)
T4b	Tumor invades adjacent structures
Regional lymph nodes (N)
NX	Regional lymph node(s) cannot be assessed
N0	No regional lymph node metastasis
N1	Metastasis in 1-2 regional lymph nodes
N2	Metastasis in 3-6 regional lymph nodes
N3	Metastasis in seven or more regional lymph nodes
N3a	Metastasis in 7-15 regional lymph nodes
N3b	Metastasis in 16 or more regional lymph nodes
Distant metastasis (M)
M0	No distant metastasis
M1	Distant metastasis

Table 2. Clinical stage/prognostic groups (cTNM) (Open Table in a new window)

Stage	T	N	M
0	Tis	N0	M0
I	T1	N0	M0
I	T2	N0	M0
IIA	T1	N1, N2, N3	M0
IIA	T2	N1, N2, N3	M0
IIB	T3	N0	M0
IIB	T4a	N0	M0
III	T3	N1, N2, N3	M0
III	T4a	N1, N2, N3	M0
IVA	Any T	Any N	M0
IVB	Any T	Any N	M1

Table 3. Pathological stage (pTNM) (Open Table in a new window)

Stage	T	N	M
0	Tis	N0	M0
IA	T1	N0	M0
IB	T1	N1	M0
IB	T2	N0	M0
II A	T1	N2	M0
	T2	N1	M0
	T3	N0	M0
II B	T1	N3	M0
	T2	N2	M0
	T3	N1	M0
	T4a	N0
	T4a	N0	M0
III A	T2	N3a	M0
	T3	N2, N1	M0
	T4a	N2	M0
	T4b	N0	M0
III B	T1, T2	N3b	M0
	T3	N3a	M0
	T4b	N1, N2	M0
III C	T3, T4a	N3b	M0
III C	T4b	N3a, N3b	M0
IV	Any T	Any N	M1

A Japanese group reported improved pretreatment discrimination of stage III/IV gastric cancer from stage I/II gastric cancer using a Clinical Stage Prediction score (CSP).^[3]See Table 4, below.

Table 4. Pretreatment gastric cancer Clinical Stage Prediction score (Open Table in a new window)

Clinical factor	Points
Carcinoembryonic antigen (CEA) elevation (≥ 5.1 ng/mL)	2
Tumor diameter ≥ 60 mm	8
Circumferential gastric involvement	2
Esophageal infiltration	2
Mucinous adenocarcinoma	1
Macroscopic type Type 0 Type 2 Type 3 Type 4	-7 10 16 10

Using a score cutoff of < 17 points for stage I/II gastric cancer and of ≥ 17 points for stage III/IV gastric cancer, the CSP had a sensitivity of 78.7%, specificity of 92.1%, positive predictive value of 86.0%, and negative predictive value of 87.5%.

Table 5. Post-neoadjuvant therapy staging and overall survival (ypTNM) (Open Table in a new window)

Stage	T	N	M	3-year survival (%)	5-year survival (%)
I	T1, T2	N0	M0	81.4	76.5
I	T1	N1	M0	81.4	76.5
II	T1	N2, N3	M0	54.8	46.3
	T2	N1, N2	M0
	T3	N0, N1	M0
	T4a	N0	M0
III	T2	N3	M0	28.8	18.3
	T3	N2, N3	M0
	T4a	N1, N2, N3	M0
	T4b	N0,N1,N2,N3	M0
IV	Any T	Any N	M1	10.2	5.7

Zhong et al developed and validated a modified ypTNM staging classification for gastric cancer, shown in Table 6, below (all stages are M0).^[4]

Table 6. Modified post-neoadjuvant therapy staging and overall survival (ypTNM) (Open Table in a new window)

Stage	T	N	5-year survival (%)
IA	T1	N0	79.1
IB	T2-3	N0	61.6
II	T1-3	N1	49.7
II	T4a	N0-1	49.7
IIIA	T1-2	N2-3	37.8
	T3-4a	N2
	T4b	N0-2
IIIB	T3-4b	N3	16.1

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Table 1. TNM classification for gastric cancer

Primary tumor (T)
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in situ: intraepithelial tumor without invasion of the lamina propria
T1	Tumor invades lamina propria, muscularis mucosae, or submucosa
T1a	Tumor invades lamina propria or muscularis mucosae
T1b	Tumor invades submucosa
T2	Tumor invades muscularis propria
T3	Tumor penetrates subserosal connective tissue without invasion of visceral peritoneum or adjacent structures
T4	Tumor invades serosa (visceral peritoneum) or adjacent structures
T4a	Tumor invades serosa (visceral peritoneum)
T4b	Tumor invades adjacent structures
Regional lymph nodes (N)
NX	Regional lymph node(s) cannot be assessed
N0	No regional lymph node metastasis
N1	Metastasis in 1-2 regional lymph nodes
N2	Metastasis in 3-6 regional lymph nodes
N3	Metastasis in seven or more regional lymph nodes
N3a	Metastasis in 7-15 regional lymph nodes
N3b	Metastasis in 16 or more regional lymph nodes
Distant metastasis (M)
M0	No distant metastasis
M1	Distant metastasis

Table 2. Clinical stage/prognostic groups (cTNM)

Stage	T	N	M
0	Tis	N0	M0
I	T1	N0	M0
I	T2	N0	M0
IIA	T1	N1, N2, N3	M0
IIA	T2	N1, N2, N3	M0
IIB	T3	N0	M0
IIB	T4a	N0	M0
III	T3	N1, N2, N3	M0
III	T4a	N1, N2, N3	M0
IVA	Any T	Any N	M0
IVB	Any T	Any N	M1

Table 3. Pathological stage (pTNM)

Stage	T	N	M
0	Tis	N0	M0
IA	T1	N0	M0
IB	T1	N1	M0
IB	T2	N0	M0
II A	T1	N2	M0
	T2	N1	M0
	T3	N0	M0
II B	T1	N3	M0
	T2	N2	M0
	T3	N1	M0
	T4a	N0
	T4a	N0	M0
III A	T2	N3a	M0
	T3	N2, N1	M0
	T4a	N2	M0
	T4b	N0	M0
III B	T1, T2	N3b	M0
	T3	N3a	M0
	T4b	N1, N2	M0
III C	T3, T4a	N3b	M0
III C	T4b	N3a, N3b	M0
IV	Any T	Any N	M1

Table 4. Pretreatment gastric cancer Clinical Stage Prediction score

Clinical factor	Points
Carcinoembryonic antigen (CEA) elevation (≥ 5.1 ng/mL)	2
Tumor diameter ≥ 60 mm	8
Circumferential gastric involvement	2
Esophageal infiltration	2
Mucinous adenocarcinoma	1
Macroscopic type Type 0 Type 2 Type 3 Type 4	-7 10 16 10

Table 5. Post-neoadjuvant therapy staging and overall survival (ypTNM)

Stage	T	N	M	3-year survival (%)	5-year survival (%)
I	T1, T2	N0	M0	81.4	76.5
I	T1	N1	M0	81.4	76.5
II	T1	N2, N3	M0	54.8	46.3
	T2	N1, N2	M0
	T3	N0, N1	M0
	T4a	N0	M0
III	T2	N3	M0	28.8	18.3
	T3	N2, N3	M0
	T4a	N1, N2, N3	M0
	T4b	N0,N1,N2,N3	M0
IV	Any T	Any N	M1	10.2	5.7