E188: Outcomes after resection of solitary colorectal liver metastases: analysis of 535 consecutive cases

The median overall survival (OS) of the whole cohort was 10 years. On multivariate analysis, factors associated with worse OS included >3 positive lymph nodes in the colon primary (HR 1.71, p< 0.001), tumor size (HR 1.04, p=0.045) and positive margin (HR 2.57, p=0.006). Disease-free interval and preoperative CEA were not prognostic of OS. To understand the clinical significance of tumor size, analysis of OS, recurrence-free survival (RFS) and hepatic recurrence was performed on size quartiles. The top-quartile of tumor size consisted of tumor >5.4 cm and had a median OS of 6.8 years. At 5-years, 72% of all patients remained tumor-free in the liver across the quartiles and there was no association between hepatic recurrence and tumor size (HR 1, p=0.588). A third of patients received adjuvant hepatic artery infusion chemotherapy (HAIC) and this was associated with improved OS (HR 0.71, p=0.04) and reduced hepatic recurrence (HR 0.56, p=0.002).

Conclusions: Patients with resected solitary CLM have excellent long-term survival that is not well predicted by traditional preoperative prognostic factors and may reflect a distinct biology.  The hepatic recurrence pattern is consistent regardless of tumor size. This suggests that a proportion of patients with solitary CLM may be protected against metastases in the remaining liver.