Appendiceal neuroendocrine tumors: Recent insights and clinical implications

Table 1 Classification and staging of appendiceal NETs according to the TNM system

Stage	T	N	M
I	Τ1	Ν0	Μ0
II	Τ1	Ν1	Μ0
	Τ2	Ν0	Μ0
III	Τ2	Ν1	Μ0
	Τ3	Any Ν	Μ0
IV	Any Τ	Any Ν	Μ1

NETs: Neuroendocrine tumors; T1: Tumor < 2 cm; T2: Tumor ≥ 2 cm but < 3 cm; T3: Tumor ≥ 3 cm; N0: No lymph node metastases; N1: Regional lymph node metastases; M0: No metastases; M1: Distant metastases.

Table 2 Recommended surgical strategies for appendiceal NETs based on specific clinical and histological characteristics

Indications	Type of operation
Tumor size < 1 cm	Appendicectomy
Tumor size 1-2 cm	Appendicectomy + Regular F/Up for 5 years
Tumor size > 2 cm	Right hemicolectomy
Location of the tumor at the base of the appendix	Right hemicolectomy
Infiltration of the cecum	Right hemicolectomy
Positive surgical resection margins	Right hemicolectomy
Appendiceal mesentery invasion	Right hemicolectomy
Metastatically infiltrated mesoappendiceal lymph node	Right hemicolectomy
Presence of undifferentiated or low differentiated cells	Right hemicolectomy
Presence of goblet cells
Goblet cell carcinoma in males	Right hemicolectomy
Goblet cell carcinoma in females (regardless of age)	Right hemicolectomy + Bilateral salpingo-oophorectomy
Peritoneal dissemination from goblet cell carcinoma	Cytoreductive surgery + Adjuvant intraperitoneal chemotherapy