Biological characteristics and treatment outcomes of metastatic or recurrent neuroendocrine tumors: tumor grade and metastatic site are important for treatment strategy.
BACKGROUND
Studies about the biology, treatment pattern, and treatment outcome of metastatic/recurrent neuroendocrine tumor (NET) have been few.


METHODS
We enrolled patients with metastatic/recurrent NET diagnosed between January 1996 and July 2007 and retrospectively analyzed.


RESULTS
A total of 103 patients were evaluated. Twenty-six patients (25.2%) had pancreatic NET, 27 (26.2%) had gastrointestinal NET, 2 (1.9%) had lung NET, 28 (27.2%) had NET from other sites, and 20 (19.4%) had NET from unknown origin. The liver was the most common metastatic site (68.9%). Thirty-four patients had grade 1 disease, 1 (1.0%) had grade 2 disease, 15 (14.6%) had grade 3 disease, 9 (8.7%) had large cell disease, and 7 (6.8%) had small cell disease.Sixty-six patients received systemic treatment (interferon, somatostatin analogues or chemotherapy), 64 patients received local treatment (TACE, radiofrequency ablation, metastasectomy, etc.). Thirty-six patients received both systemic and local treatments.Median overall survival (OS) was 29.0 months (95% confidence interval, 25.0-33.0) in the 103 patients. OS was significantly influenced by grade (p = .001). OS was 43.0, 23.0, and 29.0 months in patients who received local treatment only, systemic treatment only, and both treatments, respectively (p = .245). The median time-to-progression (TTP) was 6.0 months. Overall response rate was 34.0% and disease-control rate was 64.2%. TTP was influenced by the presence of liver metastasis (p = .011).


CONCLUSIONS
OS of metastatic/recurrent NET was different according to tumor grade. TTP was different according to metastasis site. Therefore, development of optimal treatment strategy based on the characteristics of NET is warranted.
Kim
Su-Jung
SJ
Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.
Kim
Jin Won
JW
Han
Sae-Won
SW
Oh
Do-Youn
DY
Lee
Se-Hoon
SH
Kim
Dong-Wan
DW
Im
Seock-Ah
SA
Kim
Tae-You
TY
Seog Heo
Dae
D
Bang
Yung-Jue
YJ
D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000556:secondary* / Q000628:therapy; D001932:Brain Neoplasms / Q000556:secondary* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary* / Q000628:therapy; D008175:Lung Neoplasms / Q000556:secondary* / Q000628:therapy; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000628:therapy; D018358:Neuroendocrine Tumors / Q000473:pathology* / Q000628:therapy; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult