Disappearing Colorectal Metastases After Chemotherapy: Should We Be Concerned?
Mark G. Van Vledder*, Mechteld C. De Jong, Timothy M. Pawlik, Richard D. Schulick, Luis Diaz, Michael a. Choti
Surgery, Johns Hopkins Hospital, Baltimore, MD
Background: With increasing efficacy of preoperative chemotherapy for colorectal liver metastases (CRLM), more patients will demonstrate a complete radiological response (rCR) in one or more lesions on preoperative cross-sectional imaging. We sought to investigate the rate in which these lesions remain undetected and untreated intraoperatively and the impact of residual rCR sites on postoperative outcome. Patients and Methods: Radiological response to preoperative chemotherapy was evaluated for 172 patients undergoing surgical therapy for CRLM in between 2000 and 2008. Pre-chemotherapy CT scans were compared to post-chemotherapy images and intraoperative findings. Furthermore, outcomes with regard to recurrence pattern and survival were determined.Results: rCR occurred in 179 of the 617 lesions (29%) of those treated with preoperative chemotherapy. Of these, 111 (62%) were detected intraoperatively using a combination of palpation and intraoperative ultrasonography. rCR of one or more lesions was observed in 54 patients (31%). In 26 of these patients (48%), all rCR lesions were detected intraoperatively. In 28 patients, at least one lesion remained undetected intraoperatively. Of these, 23 (82%) had rCR sites that were left untreated. When comparing outcomes between patients with completely treated vs. untreated rCR sites, one year intrahepatic recurrence rate was higher in those with untreated rCR sites (32% vs 43%, p=0.05). However, the majority of these patients were able to undergo repeat surgical therapy upon recurrence and the overall survival was not statistically different between groups (3-yr OS 78% vs. 66%, p=0.64) Conclusions: In our study, we found rCR to occur commonly in patients undergoing preoperative chemotherapy for CRLM. However, the majority of these rCR lesions were indentified intraoperatively. Among those patients with undetected and untreated lesions, long-term outcome was good despite a high rate of intrahepatic recurrence. This finding may be related to favorable tumor biology, patient selection, and opportunities for salvage surgery. Therefore, aggressive surgical therapy should be considered in patients with marked response to chemotherapy, even when all rCR sites cannot be identified.
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