Abstract: Objective To investigate the prognostic value of different stages of TNM in patients with appendiceal neuroendocrine tumors (NETs). Methods The clinical data of 40 cases of NETs were analyzed, and follow-up data were staged by the ENETS and AJCC TNM staging system. Kaplan- Miere survival curves were used to compare survival differences in patients with different stages of TNM. Results Of the 40 patients, no one was diagnosed as appendiceal NETs before surgery. Twenty-one patients were diagnosed as acute appendicitis, 16 were diagnosed as chronic appendicitis and 3 were suspected as appendiceal tumors due to thickening of the lumen before surgery. No clinical manifestations were found in 40 patients before surgery including diarrhea, abdominal pain, facial flushing, asthma- like seizures and other carcinoid syndrome performance. All patients underwent appendectomy, and appendix NETs were diagnosed by pathology after surgery. In 40 appendical NETs patients, 15 cases were classified as stage Ⅰ(37.5%), 10 cases were classified as stage ⅡA (25%), 2 cases were classified as stage ⅢA (5%), 13 cases were classified at stage ⅢB (32.5%), and no patients were classified as stage Ⅳ. The median survival times (months) were 27, 22, 21 and 18 for patients with different stages, and there were no significant differences in survival times between four stages (χ2=0.898 8，P>0.05). Conclusion The clinical features of appendical NETs are nonspecific. The diagnosis of appendical NETs is based on pathological examination and immunohistochemistry. There are no correlation between different TNM stages and prognosis of patients.

Key words: neuroendocrine tumors, appendix, neoplasm staging, prognosis, Kaplan-Meiers estimate, TNM staging