Background: To assess prospectively the safety and efficacy of Yttrium-90 microspheres in patients with unresectable liver metastases from neuroendocrine tumors.
Materials and methods: Microspheres were administered via a temporarily placed hepatic catheter. Patients were monitored prospectively. All patients were followed with laboratory and imaging studies at regular intervals to determine response rates. Toxicity and quality of life scores were measured.
Results: Nine patients (7 female) with a mean age of 58.8 years were enrolled in this prospective trial. The mean tumor load was 58.8%. The estimated percentage shunting to the lungs on MAA scans was 5.04 +/- 2.4%. Visceral artery embolization of extrahepatic arteries before treatment was performed in 6 patients. The median dose of microspheres was 2.1 +/- 0.4 GBq. A total of 12 therapy sessions was performed. The mean follow-up was 21.7 months. Technical success was 100%. No major complications occurred. Survival rates were 100, 57 and 57% for 1, 2 and 3 years, respectively. Three months after SIRT therapy partial response (PR) was seen in 6 patients (66%). Calculated reduction of liver metastasis volume was 49%. In 3 patients (33%) stable disease was seen with a calculated tumor reduction of 13%. The estimated time to progression was 11.1 months.
Conclusion: Radioembolization with (90)Y microspheres is safe and produces high response rates even with extensive tumor replacement for up to 1 year. Acute and late toxicity was very low. Further investigations compared with other local ablative techniques is warranted.