Accuracy of Modern Clinical Risk Score Including RAS Status Changes Based on Whether Patients Received Perioperative Chemotherapy for Colorectal Liver Metastases.

Background: A modified Fong clinical score (m-Fong CS) that includes the RAS mutation status has recently been proposed and offered an improved survival stratification of patients who undergo surgery and systemic chemotherapy for colorectal liver metastases (CLM). The aim of this study is to assess whether a CS that includes RAS status is influenced by whether patients receive perioperative chemotherapy. Methods: We created a new CS using multivariate analysis of data of patients who underwent hepatectomy for CLM for the first time between 2010 and 2016 at a single hospital (n = 341, 79% received perioperative chemotherapy). The resulting CS and m-Fong CS were then validated in the patient cohort at three other hospitals (n = 309). Furthermore, the applicability of the two CS in the total cohort (n = 650) was tested according to whether the patients received perioperative chemotherapy. Results: The new CS comprised mutant RAS status, ≥4 CLMs, and a CA19-9 level ≥100 U/mL (1 point per factor). Both the new CS and m-Fong CS failed to stratify the survival of the 309 patients in the validation cohort, including those who did not receive perioperative chemotherapy (29%). Both of the CS accurately stratified the survival of patients who underwent perioperative chemotherapy but not of those who underwent surgery alone. Conclusion: A CS that includes the RAS mutation status can stratify the survival of patients who undergo hepatectomy combined with perioperative chemotherapy, but it has limited value for patients who undergo surgery alone. [ABSTRACT FROM AUTHOR]