Ablative therapies for liver metastases of gastroenteropancreatic endocrine tumors.

Hepatic metastases are frequent in patients with gastroenteropancreatic (GEP) endocrine tumors. The presence of hepatic metastases affects overall prognosis and quality of life especially in the presence of debilitating functional syndromes. Surgery, although the method of choice for hepatic metastases, is usually impossible due to disease extent. Results of systemic chemotherapy are also disappointing especially in patients with metastases from midgut GEP tumors. These latter patients usually have carcinoid syndrome which can be controlled by somatostatin analogues. Other therapeutic options in the treatment of highly vascular liver metastases from GEP tumors are locoregional strategies by inducing vascular occlusion resulting in ischemia and necrosis of tumoral tissue. Surgical ligation of the hepatic artery or transient hepatic ischemia has been replaced by transcatheter arterial chemoembolization (TACE). TACE has proven effective in controlling symptoms and gives objective tumor response in about half of patients. Other regional destructive methods, used either alone or in combination with surgery, include radiofrequency ablation and cryotherapy. The latter strategies are poorly evaluated to date and are usually adjuncts to surgery and reserved for limited disease.