Outcomes After Transarterial Embolization of Neuroendocrine Tumor Liver Metastases Using Spherical Particles of Different Sizes.

PURPOSE: To evaluate initial response and overall survival of neuroendocrine tumor (NET) liver metastases initially treated with transarterial embolization (TAE) using spherical particles of different sizes.
METHODS: A single-institution retrospective review was performed of 160 patients with NET liver metastases initially treated with TAE using < 100 µm (n = 77) or only ≥ 100 µm (n = 83) spherical particles. For each patient, we evaluated: initial response by mRECIST, time to progression, overall survival, complications, primary site, tumor grade and degree of differentiation, volume of liver disease, extrahepatic disease, NET-related symptoms, comorbidities, Child-Pugh score, performance status, lobar versus selective embolization, and arteriovenous shunting.
RESULTS: Initial response was higher for TAE using particles < 100 versus TAE using only particles ≥ 100 μm (64 vs 42%, p = 0.007). Multivariate logistic regression showed that use of particles < 100 μm and liver < 50% replaced with tumor were independent predictors of a better initial response rate. There was no difference in major or minor complications between the two particle size groups. Median overall survival after TAE was 55 months for well- to moderately differentiated NET and 13 months for poorly differentiated or undifferentiated NET. There was no significant difference in survival between TAE patients treated with < 100 versus only ≥ 100-μm particles.
CONCLUSION: NET patients treated with TAE using particles < 100 μm had better initial response, but the same overall survival, compared to TAE using only particles ≥ 100 μm.