Integrating radioembolization into the treatment paradigm for metastatic neuroendocrine tumors in the liver.

Surgical resection of hepatic metastases from neuroendocrine tumors (mNETs) is controversial because the potential survival benefit of this intervention must be balanced against the risk of surgical morbidity and mortality. In patients with unresectable mNETs in the liver, radioembolization has been used to treat tumors from a range of primary sites, including carcinoid and islet cell carcinomas as well as nonfunctional, asymptomatic tumors. Initial clinical studies and retrospective studies on a large cohort of patients indicate that radioembolization is well tolerated and highly effective in achieving a durable hepatic tumor response and ameliorating symptoms. Radioembolization using Yttrium-90 ((90)Y)-labeled resin or glass microspheres offers effective disease control and possible improved quality of life and thus merits consideration as an option for both functional and nonfunctional mNETs. Benefits of this intervention seem to extend from use in early lines of treatment to salvage of refractory disease. Radioembolization also offers a potential somatostatin analog-sparing effect in symptomatic disease.