Repeat abdominal imaging with a contrast-enhanced CT scan of the abdomen in 3 to 4 months is most appropriate. This patient has an incidental finding of a metastatic low-grade carcinoid tumor that is asymptomatic and hormonally nonfunctional. It is impossible to know how long the tumor has been present. However, given the benign presentation and near-normal liver function studies, the tumor has probably been present for many years. Because urgent intervention is unlikely to be needed, expectant observation and repeat imaging studies in 3 to 4 months will be useful in establishing disease progression. For many patients, little or no change is seen on serial scans, and these patients may be followed with serial imaging studies two to three times each year. If substantial tumor progression or tumor-related symptoms develop, intervention should be considered.

Hepatic artery embolization may be effective in decreasing tumor volume in the liver or decreasing hormone production in patients with neuroendocrine tumors. However, this is an invasive procedure that carries risks of morbidity and mortality and would not be appropriate for an asymptomatic patient with small-volume, hormonally nonfunctional disease.

This patient does have a positive radiolabeled octreotide scan, indicating that somatostatin receptors are present on the tumor (as they are in most neuroendocrine tumors). Therefore, treatment with octreotide, a somatostatin analogue, could be considered in the future if the disease progresses. Although actual tumor regression following octreotide administration is rare, octreotide has been demonstrated to stabilize and delay progression of carcinoid tumors and would be an appropriate consideration if progression of this patient's tumor is seen on serial imaging.

Radiofrequency ablation is another invasive procedure that can be used to treat patients with a small number of liver lesions. However, it has no role in the treatment of patients with numerous lesions, such as the patient described here.

Systemic chemotherapy would also not be indicated in a patient with an asymptomatic neuroendocrine tumor in the absence of disease progression or disease-related symptoms.