Hepatic Arterial Embolization and Chemoembolization for the Treatment of Patients with Metastatic Neuroendocrine Tumors: Variables Affecting Response Rates and Survival

Background: The objective of this study was to determine the prognostic variables that influence response and survival in patients with metastatic neuroendocrine tumors who are treated with hepatic arterial embolization (HAE) or chemoembolization (HACE).

Methods: Patients with metastatic neuroendocrine tumors who underwent HAE or HACE were included in this retrospective study. Follow-up imaging studies were compared with baseline imaging to determine the radiologic response. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Univariate and multivariate analyses were performed to assess the prognostic variables that affected response and survival.

Results: The study included 69 patients with carcinoid tumors and 54 patients with pancreatic islet cell carcinomas. Patients who had carcinoid tumors had a higher response rate (66.7% vs. 35.2%; P = 0.0001) and had longer PFS (22.7 mos vs. 16.1 mos; P = 0.046) and OS (33.8 mos vs. 23.2 mos; P = 0.012) compared with patients who had islet cell carcinomas. For patients with carcinoid tumors, multivariate analysis identified male gender as the only independent risk factor for poor survival (P = 0.05). Octreotide was predictive marginally for PFS (P = 0.06). Patients who were treated with HAE had a higher response rate than patients who were treated with HACE (P = 0.004). For patients with islet cell carcinoma, an intact primary tumor, > or = 75% liver involvement, and extrahepatic metastases were associated with reduced OS in the univariate analysis; the presence of bone metastases was the only risk factor (P = 0.031) in the multivariate analysis. Patients who were treated with HACE had a prolonged OS (31.5 mos vs. 18.2 mos) and improved response (50% vs. 25%) compared with patients who were treated with HAE, although the differences did not reach statistical significance.

Conclusions: Patients with carcinoid tumors had better outcomes than patients with islet cell carcinomas. The addition of intraarterial chemotherapy to HAE did not improve the outcome of patients with carcinoid tumors, but it seemed to benefit patients with islet cell carcinomas. In patients who had carcinoid tumors, male gender predicted a poor outcome, and a trend toward prolonged PFS was observed in patients who received concomitant octreotide. An intact primary tumor, extensive liver disease, and bone metastases were associated with reduced survival in patients with islet cell carcinomas.