Recurrence Patterns After Resection of Colorectal Liver Metastasis are Modified by Perioperative Systemic Chemotherapy

Background This study investigated the impact of perioperative systemic chemotherapy on the recurrence rate and pattern following resection of colorectal liver metastases. Methods A retrospective cohort study was conducted in two centers. Rates and patterns of recurrence and overall survival (OS) were compared between patients treated with and without perioperative systemic chemotherapy. The clinical risk score (CRS) was used to stratify patients in low risk (CRS 0-2) and high risk (CRS 3-5) of recurrence. Results A total of 2020 patients were included, of whom 1442 (71%) received perioperative systemic chemotherapy. The median follow-up was 88 months, and 1289 patients (64%) developed a recurrence. The recurrence pattern was independent of chemotherapy in low-risk patients: intrahepatic recurrences (30% vs. 30%, p = 0.97) and extrahepatic recurrences (38% vs. 39%, p = 0.52). In high-risk patients, no difference in intrahepatic recurrences was found (48% vs. 50%, p = 0.59). However, a lower rate of extrahepatic recurrences (43% vs. 55%, p = 0.007) was observed with perioperative systemic chemotherapy, mainly due to a reduction in pulmonary recurrences (25% vs. 35%, p = 0.007). In competing risk analysis, the cumulative incidence of extrahepatic recurrence was significantly lower with perioperative systemic chemotherapy in high-risk patients only (5-year cumulative incidence 44% vs. 59%, p < 0.001). Perioperative chemotherapy was associated with improved OS in high-risk patients (adjusted HR 0.73, 95% CI 0.57-0.94, p = 0.02), but not in low-risk patients (adjusted HR 0.99, 95% CI 0.82-1.19, p = 0.90). Conclusions Perioperative systemic chemotherapy had no association with intrahepatic recurrence, but was associated with fewer pulmonary recurrences and superior OS in high-risk patients only.