Safety and Feasibility of Integrating Yttrium-90 Radioembolization With Capecitabine-Temozolomide for Grade 2 Liver-Dominant Metastatic Neuroendocrine Tumors.

Objectives: An integrated protocol combining capecitibine-temozolomide with yttrium-90 radioembolization (CapTemY90) for liver-dominant grade 2 neuroendocrine tumors (NETs) was designed in the hope of achieving synergistic improvement in liver disease control with no more than additive toxicities. This report describes the feasibility and safety of this regimen.

Methods: Twenty-one patients with unresectable grade 2 NET liver-dominant metastases without contraindications to radioembolization or to CapTem initiated therapy with capecitabine 600 mg/m twice daily for 14 days and temozolomide 150 to 200 mg/m in 2 divided doses on days 10 to 14, with 14 days between cycles. During the first cycle, simulation angiography was performed. The dominant lobe was radioembolized on day 7 of the second cycle. In patients with bilobar disease, the other lobe was treated on day 7 of the third or fourth cycle.

Results: Nineteen of 21 patients completed the protocol. Adverse events were as expected. Objective response rate was 74% in the liver and 55% for extrahepatic tumor. Median progression-free survival was not reached. Progression-free survival at 3 years was 67%, with 74% progression-free in the liver.

Conclusions: CapTemY90 is feasible and safe for grade 2 NETs. Toxicities were additive. Oncologic outcomes suggest synergy.