BACKGROUND: The importance of preoperative chemotherapy in a multimodality management of patients with colorectal liver metastases (CRLM) has been demonstrated. We analyse the carcinoembryonic antigen (CEA) changes following neoadjuvant chemotherapy in patients with CRLM who underwent liver resection.METHODS: The final cohort included 107 eligible patients. Increased CEA levels following neoadjuvant chemotherapy were defined as the increase of baseline CEA level at diagnosis of CRLM compared with the CEA level after completion of neoadjuvant chemotherapy. Disease-free survival (DFS), post-recurrence survival (PRS) and overall survival (OS) were calculated using both Kaplan-Meier and multivariate Cox-regression methods.RESULTS: CEA increase was associated with decreased PRS and OS (HR 2.69; 95 % CI, 1.28-5.63; p = 0.009, and HR 2.50; 95 % CI, 1.12-5.56; p = 0.025, respectively) in multivariate analysis, but there was no association between CEA changes and DFS. CEA increase was only associated with disease progression during preoperative chemotherapy (p = 0.014). Interestingly, this association was not absolute, as only 5 of the 11 patients with disease progression demonstrated CEA increase. Regarding the remaining 12 patients with CEA increase, according to RECIST criteria, eight patients demonstrated partial response and four patients stable disease.CONCLUSION: In this study, we demonstrated the CEA increase following neoadjuvant chemotherapy as an adverse prognostic factor for PRS, and OS but not for DFS in patients undergoing liver resection for liver-only colorectal metastases.