Somatostatin analogs for gastric carcinoids: For many, but not all

Table 1 Characteristics of gastric carcinoids according to the European Neuroendocrine Tumor Society guidelines[8]

	GC1	GC2	GC3
Proportion among g-NEN	70%-80%	5%-6%	14%-25%
Grading	NET G1	NET G1-G2	NEC G3
Associated conditions	CAG	Gastrinoma/MEN-1	None
Serum gastrin values	Elevated	Elevated	Normal
Metastases	2%-5%	10%-30%	50%-100%
Mortality rate	0%	< 10%	25%-30%

GC 1, 2 and 3: Type I, II and III gastric carcinoids; NENs: Neuroendocrine neoplasms; CAG: Chronic atrophic gastritis; MEN-1: Multiple endocrine neoplasia type I.

Table 2 Grading of neuroendocrine neoplasms according to the World Health Organization 2010 classification[8]

Histological classification	G1 (low grade)	G2 (intermediate grade)	G3 (high grade)
Mitotic rate (n/10 HPF)	< 2	2–20	> 20
Ki-67 index	< 3%	3%–20%	> 20%

Table 3 Scoring staging system according to tumor-node-metastasis[26]

T-primary tumor
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	In-situ tumor/dysplasia (< 0.5 mm)
T1	Tumor invades lamina propria or submucosa and < 1 cm
T2	Tumor invades muscularis propria or subserosa or > 1 cm
T3	Tumor penetrates serosa
T4	Tumor penetrates serosa and/or invades adjacent structures
N-regional lymph nodes
NX	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis
N1	Regional lymph node metastasis
M-metastases
MX	Distant metastasis cannot be assessed
M0	No distant metastases
M1	Distant metastases
Stage
0	Tis N0 M0
1	T1 N0 M0
2A	T2 N0 M0
2B	T3 N0 M0
3A	T4 N0 M0
3B	Any T N1 M0
4	Any T Any N M1