Disappearing Colorectal Liver Metastases after Chemotherapy: Should we be Concerned?

Background: With increasing efficacy of preoperative chemotherapy for colorectal cancer, more patients will present with one or more disappearing liver metastases (DLM) on preoperative cross-sectional imaging. Patients and Methods: A retrospective review was conducted evaluating the radiological response to preoperative chemotherapy for 168 patients undergoing surgical therapy for colorectal liver metastases at Johns Hopkins Hospital between 2000 and 2008. Results: Forty patients (23. 8%) had one or more DLM, accounting for a total of 127 lesions. In 22 patients (55%), all DLM sites were treated during surgery. Of the 17 patients with unidentified, untreated DLM, ten patients (59%) developed a local recurrence at the initial site, half of which also developed recurrences in other sites. While the intrahepatic recurrence rate was higher for patients with DLM left in situ (p = 0.04), the 1-, 3-, and 5-year overall survival rate was not significantly different for patients with DLM left in situ (93.8%, 63.5%, and 63.5%, respectively) when compared to patients with a radiological chemotherapy response in whom all original disease sites were surgically treated (92.3%, 70.8%, and 46.2%, respectively; p = 0.66). Conclusions: DLM were frequently observed in patients undergoing preoperative chemotherapy for liver metastases. Survival was comparable in patients with untreated DLM, in spite of high intrahepatic recurrence rates seen in these patients. Therefore, aggressive surgical therapy should be considered in patients with marked response to chemotherapy, even when all DLM sites cannot be identified.