Early gastric cancer: A challenge in Western countries

Table 1 Vienna classification

Category	Definition	Treatment
1	Negative for dysplasia/neoplasia	No treatment
2	Indefinite for dysplasia/neoplasia	Follow-up, recheck
3	Non-invasive, low-grade dysplasia	Follow-up
4	Non-invasive, high-grade dysplasia	Endoscopic resection, surgery
4.1	High-grade adenoma/dysplasia
4.2	Non-invasive carcinoma (CIS)
4.3	Suspicious of invasive carcinoma
5	Invasive neoplasia	Surgery (recently ESD)
5.1	Intramucosal carcinoma
M1	Mucosa only
M2	Mucosa with preservation of muscularis mucosae
M3	Not further than muscularis mucosae
5.2	Submucosal carcinoma or beyond
sm1	Invasion of muscularis mucosae < 0.5 µm
sm2	Invasion of muscularis mucosae > 0.5 µm

CIS: Cancer in situ; ESD: Endoscopic submucosal dissection.

Table 2 Criteria for endoscopic mucosal resection, endoscopic submucosal dissection and surgery

	Mucosal cancer				Submucosal cancer
	No ulcer		Ulcer present		SM1	SM2
Size	≤ 20	> 20	≤ 30	> 30	≤ 30	Any size
Differentiated	Y	G	G	R	G	R
Undifferentiated	Gray	R	R	R	R	R

Y: Yellow is guideline criteria for endoscopic mucosal resection; G: Green is guideline criteria for endoscopic submucosal dissection; R: Red is surgery; Gray: Expanded indication for endoscopic submucosal dissection; SM1: Submucosal invasion < 500 µm; SM2: Submucosal invasion ≥ 500 µm.

Table 3 Laparoscopic endoscopic cooperative procedures

Procedure	Characteristics
Laparoscopic endoscopic cooperative surgery	Endoscopic dissection of the mucosal or submucosal layers with laparoscopic seromuscular resection.
Endoscope-assisted laparoscopic wedge resection	The procedure is performed to remove tumors with a laparoscope after localization by an intraoperative endoscope. EAWR is difficult to implement in sites where strictures may occur, such as pylorus and the gastroesophageal junction.
Laparoscopy-assisted endoscopic resection	The concept of LAER is contrary to that of EAWR. The procedure is an ESD procedure assisted by laparoscopy.
Endoscope-assisted laparoscopic transgastric resection	The procedure involves opening of the gastric wall under the direct view of an endoscope, tagging the tumor with a laparoscopic suture and performing wedge resection with a laparoscopic stapler.
Laparoscopic intragastric surgery	Procedure can be used in laparoscopic surgery performed within the stomach. The incision in the wall of the stomach is minimized and laparoscopic trocars are inserted into the gastric lumen.
Single-incision intragastric resection	This is a single-port laparoscopic surgery.
Endoscopic submucosal dissection with laparoscopic lymph node dissection	This procedure is the same as LAER with laparoscopic perigastric lymph node dissection. The advantage is that the stomach can be preserved. However, the main procedure is ESD, which requires a skilled endoscopist.
Single-incision endoscopic submucosa dissection with laparoscopic lymph node dissection	The procedure is similar to SI-IGR, where sentinel node navigation surgery with unilateral perigastric laparoscopic lymph node dissection is performed with a single-port. Then ESD is performed through a single-port.
Laparoscopy-assisted endoscopic full-thickness resection	If the tumor invades deeper than the muscle layer of the wall of the stomach, full-thickness resection with an endoscope is performed and a laparoscope is used for repair.
Non-exposed wall-inversion surgery	The procedure was developed so that EFTR could be performed without spillage. The disadvantages are that the procedure time is long, as it involves ESD and endoscopic closure, and it is difficult to apply to the pyloric area and gastroesophageal junction.
Clean no-exposure technique	Similar to NEWS, this procedure has also been developed to avoid cancer cell spillage. Clean-NET can be applied to EGCs in most locations, except for pyloric area and gastroesophageal junction.

EAWR: Endoscope-assisted laparoscopic wedge resection; LAER: Laparoscopy-assisted endoscopic resection; ESD: Endoscopic submucosal dissection; EATR: Endoscope-assisted laparoscopic transgastric resection; SI-IGR: Single-incision intragastric resection; EFTR: Endoscopic full thickness resection; NEWS: Non-exposed wall-inversion surgery; Clean-NET: Clean no-exposure technique; EGC: Early gastric cancer.

Table 4 Anatomical definitions of lymph node stations

Nr.	Definition
1	Right paracardial LNs, including those along the first branch of the ascending limb of the left gastric artery
2	Left paracardial LNs including those along the esophagocardiac branch of the left subphrenic artery
3	3a: Lesser curvature LNs along the branches of the left gastric artery; 3b: Lesser curvature LNs along the 2nd branch and distal part of the right gastric artery
4	(1) 4sa: Left greater curvature LNs along the short gastric arteries (perigastric area); (2) 4sb: Left greater curvature LNs along the left gastroepiploic artery (perigastric area); and (3) 4d: Right greater curvature LNs along the 2nd branch and distal part of the right gastroepiploic artery
5	Suprapyloric LNs along the 1st branch and proximal part of the right gastric artery
6	Infrapyloric LNs along the first branch and proximal part of the right gastroepiploic artery down to the confluence of the right gastroepiploic vein and the anterior superior pancreatoduodenal vein
7	LNs along the trunk of left gastric artery between its root and the origin of its ascending branch
8	8a: Anterosuperior LNs along the common hepatic artery; 8p: Posterior LNs along the common hepatic artery
9	Coeliac artery
10	Splenic hilar LNs including those adjacent to the splenic artery distal to the pancreatic tail, and those on the roots of the short gastric arteries and those along the left gastroepiploic artery proximal to its 1st gastric branch
11	(1) 11p: Proximal splenic artery LNs from its origin to halfway between its origin and the pancreatic tail end; and (2) 11d: Distal splenic artery LNs from halfway between its origin and the pancreatic tail end to the end of the pancreatic tail
12	(1) 12a: Hepatoduodenal ligament LNs along the proper hepatic artery, in the caudal half between the confluence of the right and left hepatic ducts and the upper border of the pancreas; (2) 12b: Hepatoduodenal ligament LNs along the bile duct, in the caudal half between the confluence of the right and left hepatic ducts and the upper border of the pancreas; and (3) 12p: Hepatoduodenal ligament LNs along the portal vein in the caudal half between the confluence of the right and left hepatic ducts and the upper border of the pancreas
13	LNs on the posterior surface of the pancreatic head cranial to the duodenal papilla
14	LNs along the superior mesenteric vein
15	LNs along the middle colic vessels
16	(1) 16a1: Paraaortic LNs in the diaphragmatic aortic hiatus; (2) 16a2: Paraaortic LNs between the upper margin of the origin of the celiac artery and the lower border of the left renal vein; (3) 16b1: Paraaortic LNs between the lower border of the left renal vein and the upper border of the origin of the inferior mesenteric artery; and (4) 16b2: Paraaortic LNs between the upper border of the origin of the inferior mesenteric artery and the aortic bifurcation
17	LNs on the anterior surface of the pancreatic head beneath the pancreatic sheath
18	LNs along the inferior border of the pancreatic body
19	Infradiaphragmatic LNs predominantly along the subphrenic artery
20	Paraesophageal LNs in the diaphragmatic esophageal hiatus

LNs: Lymph nodes.

Table 5 Extent of systematic lymphadenectomy according to the type (total or distal) of gastrectomy indicated

Lymphadenectomy	Gastrectomy
	Total	Distal
D1	Lymph node stations from N. 1 to 7	Lymph node stations N. 1, 3, 4sb, 4d, 5, 6 and 7
D1+	D1 stations plus stations N. 8a, 9 and 11p	D1 stations plus stations N. 8a and 9
D2	D1 stations plus stations N. 8a, 9, 10, 11p, 11d and 12a	D1 stations plus stations N. 8a, 9, 11p and 12a.