Elevated neutrophil to lymphocyte ratio might predict poor prognosis for colorectal liver metastasis after percutaneous radiofrequency ablation

Purpose: Elevated neutrophil to lymphocyte ratio (NLR) has been shown to be a predictor of poor survival in certain malignancies. We hypothesised NLR might predict prognosis for patients with colorectal liver metastasis (CRLM) undergoing percutaneous radiofrequency ablation (RFA). Patients and methods: A cohort of 92 consecutive patients with metachronous CRLM treated with RFA was retrospectively reviewed. Baseline clinico-pathological characteristics, recurrence, overall and disease-free survival were compared according to preoperative NLR level. Prognostic factors were assessed by multivariate analysis. Results: Elevated NLR (> 5) was recorded in 21 patients (22.8%). No correlations between NLR and clinico-pathological characteristics were identified. Complete ablation was achieved in 90 patients (97.8%). After RFA, extrahepatic metastases (p = 0.015) were significantly higher in the elevated NLR group whilst local (p = 0.526) and intrahepatic (p = 0.715) recurrence. The 1, 3 and 5 years overall survival rates of 92 patients were 86.5%, 74.1%, 36.3%, and disease-free survival was 64.3%, 32.8%, 22.4% respectively. Multivariate analysis showed that NLR was an independent prognostic factor for both overall (p = 0.039, HR = 3.59, 95% CI = 1.54-9.67) and disease-free survival (p = 0.022, HR = 3.19, 95% CI 1.87-8.24). The 1, 3, 5 years overall survival rates were 86.9%, 61.1%, 41.7% for the normal NLR group, and 85.2%, 53.2%, 18.4% for the elevated NLR group respectively (p = 0.036); the corresponding disease-free survival was 64.9%, 38.7%, 26.7% and 47.6%, 14.3%, 9.5% respectively (p = 0.047). Conclusion: Elevated NLR (> 5) might predict more extrahepatic metastasis and poorer survival for patients with CRLM after RFA.