The Preoperative Lymphocyte-to-Monocyte Ratio is Prognostic of Clinical Outcomes for Patients with Liver-Only Colorectal Metastases in the Neoadjuvant Setting.

Background: Circulating monocyte-derived, tumor-associated macrophages are associated with a poor prognosis for various cancers. Conversely, circulating lymphocytes are the source of tumor-infiltrating lymphocytes, which are associated with an improved prognosis. This study evaluated the prognostic value of the preoperative blood lymphocyte-to-monocyte ratio (LMR) for patients undergoing hepatectomy for liver-only colorectal metastases.

Methods: This retrospective study examined 140 consecutive patients with liver-only colorectal metastases. Disease-free survival (DFS), post-recurrence survival (PRS), cancer-specific survival (CSS), and overall survival (OS) were analyzed in relation to LMR values using both Kaplan-Meier and multivariate Cox-regression methods.

Results: In the multivariate analysis, high LMR (>3) was significantly associated with increased OS [hazard ratio (HR), 2.43; 95 % confidence interval (CI), 1.32-4.48; P = 0.004], CSS (HR 2.15; 95 % CI 1.13-4.10; P = 0.020), and PRS (HR 2.15; 95 % CI 1.15-4.01; P = 0.016) but not with DFS. An LMR lower than 3 may have been associated with decreased CSS and PRS by increasing the rate of multifocal recurrence (P = 0.063). In the multivariate analysis comparing LMR, the neutrophil-lymphocyte ratio, and the platelet-lymphocyte ratio, LMR remained the only significant prognostic variable of CSS.

Conclusion: This study identified preoperative LMR as an independent prognostic factor for PRS, CSS, and OS but not for DFS in patients undergoing hepatectomy for liver-only colorectal metastases. In the future, interventions to augment immune function could improve survival for low-LMR patients.