Efficacy of risk-stratified indicators for adjuvant chemotherapy with fluorouracil and oxaliplatin after hepatectomy for colorectal cancer liver metastasis Running title: Risk-stratified indication for doublet AC after hepatectomy for CRLM

Background: The recurrence rate after hepatectomy for colorectal cancer liver metastasis (CRLM) is high, and there is no consensus regarding the effect of adjuvant chemotherapy (AC) using oxaliplatin (doublet AC) in these patients.Methods: The present study included 91 patients who underwent hepatectomy for complete resection at our hospitals between 2008 and 2018. Based on whether or not they had undergone doublet AC, patients were divided into AC (n=35) and non-AC (n=56) groups. Recurrent risk was evaluated by Memorial Sloan Kettering Cancer Center clinical risk score (MSKCC-CRS).Results: The number of females and median age were higher in the AC group (51.4% vs 25.0%, p=0.010 and 67 vs 61 years, p=0.012, respectively). Doublet AC was an independent prognostic factor for 5-year relapse-free survival (hazard ratio, 0.225; 95%CI, 0.097–0.522; p