Radioembolization with selective internal radiation microspheres for neuroendocrine liver metastases

There are limited effective treatment options available and a poor 5-year survival for patients with inoperable neuroendocrine liver metastases (NETLMs). In this study, the authors prospectively assessed the safety and efficacy of treatment with yttrium 90 ((90)Y) radioactive microspheres for patients with unresectable NETLMs.

Radioactive (90)Y resin microspheres (selective internal radiation [SIR-Spheres]) were administered through a temporarily placed percutaneous hepatic artery catheter concomitantly with a 7-day systemic infusion of 5-fluorouracil to patients with progressive, unresectable NETLMs. Patients were monitored prospectively, and the response to treatment was measured by using cancer markers and tumor size on computed tomography imaging studies.

Thirty-four patients (22 men) with a mean age 61 years (range, 32-79 years) who had unresectable NETLMs were treated between December 2003 and December 2005. The mean (+/-standard error) follow-up was 35.2 +/- 3.2 months. The site of the primary neuroendocrine tumor was the bronchus in 1 patient, the medullary thyroid in 2 patients, gastrointestinal in 15 patients, the pancreas in 8 patients, and of unknown origin in 8 patients. The tumors were classified as vipoma (1 tumor), somatostatinoma (1 tumor), glucagonoma (2 tumors), large cell (3 tumors), carcinoid (25 tumors), and of unknown origin (2 tumors). Complications after (90)Y radioembolization included abdominal pain, which was mild to severe; nausea and fever; and lethargy that lasted from 1 week to 1 month. Two patients developed biopsy-proven radiation gastritis, 1 patient developed a duodenal ulcer, and there was 1 early death from liver dysfunction and pneumonia. Subjective changes from recorded baseline hormone symptoms were reported every 3 months. Symptomatic responses were observed in 18 of 33 patients (55%) at 3 months and in 16 of 32 patients (50%) at 6 months. Radiologic liver responses were observed in 50% of patients and included 6 (18%) complete responses and 11 (32%) partial responses, and the mean overall survival was 29.4 +/- 3.4 months). In patients who had evaluable chromogranin A (CgA) marker levels, there was a fall in CgA marker levels after (90)Y radioembolization in 19 patients (26%) at 1 month, in 19 patients (41%) at 3 months, in 15 patients (43%) at 6 months, in 11 patients (42%) at 12 months, in 8 patients (38%) at 24 months, and in 3 patients (46%) at 30 months.

In this open study of 34 patients, the results demonstrated that radioembolization with (90)Y resin microspheres can achieve relatively long-term responses in some patients with nonresectable NETLMs.