Retrospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 28, 2016; 22(16): 4211-4218
Published online Apr 28, 2016. doi: 10.3748/wjg.v22.i16.4211
Lymphocyte-to-monocyte ratio predicts survival after radiofrequency ablation for colorectal liver metastases
Antonio Facciorusso, Valentina Del Prete, Nicola Crucinio, Gaetano Serviddio, Gianluigi Vendemiale, Nicola Muscatiello
Antonio Facciorusso, Valentina Del Prete, Nicola Crucinio, Nicola Muscatiello, Gastroenterology Unit, Department of Medical Sciences, University of Foggia, 71100 Foggia, Italy
Gaetano Serviddio, Gianluigi Vendemiale, Internal Medicine Unit, University of Foggia, 71100 Foggia, Italy
Author contributions: Facciorusso A designed the study, performed the statistical analysis and wrote the paper; Crucinio N performed the treatment procedures; Del Prete V and Muscatiello N collected the data; Vendemiale G and Serviddio G revised the paper.
Institutional review board statement: This study was approved by the Institutional Review Board of the University of Foggia for retrospective evaluation of de-identified patients.
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: None of the authors have received fees for serving as a speaker or are consultant/advisory board member for any organizations. None of the authors have received research funding from any organizations. None of the authors are employees of any organizations. None of the authors own stocks and/or share in any organizations. None of the authors own patents.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Antonio Facciorusso, MD, Gastroenterology Unit, Department of Medical Sciences, University of Foggia, Viale L.Pinto, 1, 71100 Foggia, Italy. antonio.facciorusso@virgilio.it
Telephone: +39-881-732154 Fax: +39-881-732135
Received: December 12, 2015
Peer-review started: December 12, 2015
First decision: December 30, 2015
Revised: December 31, 2015
Accepted: January 30, 2016
Article in press: January 30, 2016
Published online: April 28, 2016
Processing time: 129 Days and 6.3 Hours
Abstract

AIM: To test the correlation between lymphocyte-to-monocyte ratio (LMR) and survival after radiofrequency ablation (RFA) for colorectal liver metastasis (CLMs).

METHODS: From July 2003 to Feb 2012, 127 consecutive patients with 193 histologically-proven unresectable CLMs were treated with percutaneous RFA at the University of Foggia. All patients had undergone primary colorectal tumor resection before RFA and received systemic chemotherapy. LMR was calculated by dividing lymphocyte count by monocyte count assessed at baseline. Treatment-related toxicity was defined as any adverse events occurred within 4 wk after the procedure. Overall survival (OS) and time to recurrence (TTR) were estimated from the date of RFA by Kaplan-Meier with plots and median (95%CI). The inferential analysis for time to event data was conducted using the Cox univariate and multivariate regression model to estimate hazard ratios (HR) and 95%CI. Statistically significant variables from the univariate Cox analysis were considered for the multivariate models.

RESULTS: Median age was 66 years (range 38-88) and patients were prevalently male (69.2%). Median LMR was 4.38% (0.79-88) whereas median number of nodules was 2 (1-3) with a median maximum diameter of 27 mm (10-45). Median OS was 38 mo (34-53) and survival rate (SR) was 89.4%, 40.4% and 33.3% at 1, 4 and 5 years respectively in the whole cohort. Running log-rank test analysis found 3.96% as the most significant prognostic cut-off point for LMR and stratifying the study population by this LMR value median OS resulted 55 mo (37-69) in patients with LMR > 3.96% and 34 (26-39) mo in patients with LMR ≤ 3.96% (HR = 0.53, 0.34-0.85, P = 0.007). Nodule size and LMR were the only significant predictors for OS in multivariate analysis. Median TTR was 29 mo (22-35) with a recurrence-free survival (RFS) rate of 72.6%, 32.1% and 21.8% at 1, 4 and 5 years, respectively in the whole study group. Nodule size and LMR were confirmed as significant prognostic factors for TTR in multivariate Cox regression. TTR, when stratified by LMR, was 35 mo (28-57) in the group > 3.96% and 25 mo (18-30) in the group ≤ 3.96% (P = 0.02).

CONCLUSION: Our study provides support for the use of LMR as a novel predictor of outcome for CLM patients.

Keywords: Colorectal liver metastasis, Radiofrequency ablation, Survival, Prognosis, Regression

Core tip: This is a retrospective study to test the correlation between baseline lymphocyte-to-monocyte ratio (LMR) and survival outcomes in colorectal liver metastasis patients treated with radiofrequency ablation. Median overall survival (OS) was 55 mo in patients with LMR > 3.96% and 34 mo in patients with LMR ≤ 3.96% (P = 0.007). Time to recurrence (TTR) was 35 mo in the group > 3.96% and 25 mo in the group ≤ 3.96% (P = 0.02). Nodule size and LMR were the only significant predictors either for OS and for TTR in multivariate analysis. LMR was useful as clinical predictor of survival outcomes.