Treatment response to transcatheter arterial embolization and chemoembolization in primary and metastatic tumors of the liver

Introduction. Transcatheter arterial embolization (TAE) and chemoembolization (TACE) are increasingly used to treat unresectable primary and metastatic liver tumors. The purpose of this study was to determine the objective response to TAE and TACE in unresectable hepatic malignancies and to identify clinicopathologic predictors of response. Materials and methods. Seventy-nine consecutive patients who underwent 119 TAE/TACE procedures between 1998 and 2006 were reviewed. The change in maximal diameter of 121 evaluable lesions in 56 patients was calculated from pre and post-procedure imaging. Response rates were determined using Response Evaluation Criteria in Solid Tumors (RECIST) guidelines. The Kaplan-Meier method was used to compare survival in responders vs. non-responders and in primary vs. metastatic histologies. Results. TAE and TACE resulted in a mean decrease in lesion size of 10.3%±1.9% (p<0.001). TACE (vs. TAE) and carcinoid tumors were associated with a greater response (p<0.05). Lesion response was not predicted by pre-treatment size, vascularity, or histology. The RECIST partial response (PR) rate was 12.3% and all partial responders were in the TACE group. Neuroendocrine tumors, and specifically carcinoid lesions, had a significantly greater PR rate (p<0.05). Overall survival, however, was not associated with histology or radiologic response. Discussion. TAE and TACE produce a significant objective treatment response by RECIST criteria. Response is greatest in neuroendocrine tumors and is independent of vascularity and lesion size. TACE appears to be superior to TAE. Although an association of response with improved survival was not demonstrated, large cohort studies are necessary to further define this relationship.