Clinical implications of disappearing colorectal liver metastases have changed in the era of hepatocyte-specific MRI and contrast-enhanced intraoperative ultrasonography

Abstract

BackgroundClinical implication of disappearing liver metastases (DLMs) from colorectal cancer after chemotherapy needs to be reviewed in the era of modern imaging studies. MethodsBetween 2010 and 2015, 184 patients underwent curative hepatectomy for colorectal liver metastases following preoperative chemotherapy. The sites of metastases detected on pre-chemotherapy CE-CT were examined post-chemotherapy using CE-CT, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI), and contrast-enhanced intraoperative ultrasonography (CE-IOUS). DLMs were defined as tumors that disappeared on CE-CT post chemotherapy. The detection rate of DLMs with EOB-MRI and CE-IOUS were assessed, and the outcome of DLMs resected and those left in place were reviewed. ResultsA total of 275 DLMs were noted in 59 patients. On EOB-MRI, 71 lesions (26%) were visible and were resected, 92% (65/71) of which contained viable disease. Using CE-IOUS, an additional 94 lesions were identified. A total of 165 DLMs (60%) were identified and resected by sequential use of EOB-MRI and CE-IOUS, 77% (127/165) of which contained viable disease. Of 110 DLMs not identified, 68 were resected, 4% (3/68) of which contained viable disease. Among 42 lesions left in place, 6 (14%) recurred during the median follow-up period of 27 (9–72) months. DiscussionEOB-MRI and CE-IOUS exploration identified clinically relevant DLMs containing viable disease with a high level of accuracy.