Background: The study aimed to evaluate patients' outcomes and prognosis with metastatic gastrointestinal neuroendocrine tumors (mgNET) who treated temozolomide and capecitabine (CAPTEM). Methods: The data of forty-three patients were retrospectively evaluated. Clinicopathological features and treatment approaches were recorded. Kaplan-Meier analysis was used for overall survival (OS) and progression-free survival (PFS). Prognostic factors were assessed with Cox-regression analysis. Results: Median age was 59 (27-85) years. The number of male and female patients was 23 (%53.5) and 20 (%46.5), respectively. Pancreas (%51.2) was the most common site of the tumor. The number of patients with well- and poorly-differentiated mgNET was 38 (%88.4) and 5 (%11.6), respectively. The most common metastatic sites were liver (%62.8), lymph node (%58.1), and bone (%18.6). Eleven (%25.6) of the patients previously had undergone surgery, and some patients received radiotherapy (%9.5), chemotherapy (%19), and nuclear therapy (%9.3). Also, patients received octreotide (%86) or lanreotide (%14) with CAPTEM. In patients with well-differentiated mgNET, median PFS was 17.4 months, and disease control ratio %79.4 (%3-complete response, %38.2-partial response, and %38.2-stable response). No response observed in patients with poorly differianted mgNET, and the median PFS was calculated as 4.5 months. Grade 1-2 toxicity was observed in 34 (%79.1) of the patients, and grade 3-4 toxicity in 8 (%18.6). Four (%9.5) patients discontinued therapy for the toxicity. The most common toxicities were anemia (%37.2), thrombocytopenia (%25.6), and fatigue (%16.3). At a median follow-up of 33.8 (2.9-172.73) months, the ratio of five-years OS was %61. In multivariate analysis; gender (p=0.008), age (p=0.007), and Ki-67 levels (p=0.011) were a statistically significant for OS. However, the site of the tumor (p=0.186), number of metastatic sites (p=0.255), and type of somatostatin receptor ligand (p=0.903) were not. Conclusions: In the study, we showed that CAPTEM + somatostatin receptor ligands (octreotide or lanreotide) were effective and well-tolerated in patients with well-differentiated mgNET. But, it was not effective in patients with poorly-differentiated mgNET. Male gender, aged over 60 years, and tumor with a high level of Ki-67 were negative prognostic factors.

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