Prognostic role of infracentimetric colorectal liver metastases

Background The number of lesions and the size of the largest (CRLMmax) have been widely investigated as prognostic factors in patients with colorectal liver metastases (CRLM). The aim of the present study was to assess whether, in patients undergoing curative liver resection, the presence of infracentimetric lesions could affect recurrence-free survival (RFS) and overall survival (OS). Methods Patients who underwent a liver resection for CRLM between 2001 and 2019 were included. The size of CRLM was measured on the surgical specimen. The best cut-off of the smallest lesion (CRLMmin) associated with RFS was determined through the time-dependent ROC analysis. A multivariate Cox regression analysis was carried out. Results Overall, 227 patients were included. Median follow-up time was 50 months [IQR 26–84]. Recurrence occurred for 151 (66.5%) patients (liver recurrence in 67.5%, while exclusive extra-hepatic recurrence in 32.5%). The best cut-off for CRLMmin associated with RFS was 9 mm, with 12- and 24-month td-AUC 0.56 and 0.52 respectively. CRLMmin ≤ 9 mm was found to be an independent prognostic factor that impairs RFS at multivariate analysis (HR 1.534 (1.02–2.32), p = 0.042). In particular, CRLMmin ≤ 9 mm was correlated with impaired hepatic RFS (HR 1.860 (1.15–3.01), p = 0.011), but not extra-hepatic RFS. Conclusions Infracentimetric metastases (≤ 9 mm) are an independent prognostic factor that impairs hepatic RFS. This result suggests the potential benefit of neoadjuvant chemotherapy (CT) also in selected patients with initially resectable lesions, in case of CRLM ≤ 9 mm on preoperative imaging.