ASO Visual Abstract: The Usefulness of Total Tumor Volume as a Prognostic Factor and in Selecting the Optimal Treatment Strategy of Chemotherapeutic Intervention in Patients with Colorectal Liver Metastases

Background Few reports have discussed the association between total tumor volume (TTV) and prognosis in patients with colorectal liver metastases (CRLM). The present study aimed to evaluate the usefulness of TTV for predicting recurrence-free survival and overall survival (OS) in patients receiving initial hepatic resection or chemotherapy, and to investigate the value of TTV as an indicator for optimal treatment selection for patients with CRLM. Patients and Methods This retrospective cohort study included patients with CRLM who underwent hepatic resection ( n = 93) or chemotherapy ( n = 78) at the Kobe University Hospital. TTV was measured using 3D construction software and computed tomography images. Results A TTV of 100 cm 3 has been previously reported as a significant cut-off value for predicting OS of CRLM patients receiving initial hepatic resection. For patients receiving hepatic resection, the OS for those with a TTV ≥ 100 cm 3 was significantly reduced compared with those with a TTV < 100 cm 3 . For patients receiving initial chemotherapy, there were no significant differences between the groups divided according to TTV cut-offs. Regarding OS of patients with TTV ≥ 100 cm 3 , there was no significant difference between hepatic resection and chemotherapy ( p = 0.160). Conclusions TTV can be a predictive factor of OS for hepatic resection, unlike for initial chemotherapy treatment. The lack of significant difference in OS for CRLM patients with TTV ≥ 100 cm 3 , regardless of initial treatment, suggests that chemotherapeutic intervention preceding hepatic resection may be indicated for such patients.