Neutrophil-lymphocyte ratio as a prognostic factor for stereotactic body radiotherapy treatment of metastatic liver tumors

BACKGROUND: The neutrophil-lymphocyte ratio (NLR) has been proposed as an indicator of systemic inflammatory response and may be able to predict clinical outcomes in patients with malignant solid tumors. However, the relationship between NLR and the prognosis of liver metastasis after stereotactic body radiotherapy (SBRT) is not well established. METHODS: Patients with liver metastatic tumors who underwent SBRT in our center between 2015 and 2018 were enrolled, and their data were retrospectively analyzed. The patient’ baseline total white blood cell (WBC), neutrophil, lymphocyte, and platelet counts were recorded, along with their mean platelet volume (MPV) and red blood cell distribution width (RDW). The cut-off values for NLR and platelet-lymphocyte ratio (PLR) were determined by receiver operating characteristic (ROC) curves. Local control (LC) and overall survival (OS) were calculated using the Kaplan-Meier method. The Cox proportional hazards model was used to study significant variable line and factors associated with OS. RESULTS: A total of 65 patients with 82 lesions were enrolled. The median duration follow-up was 21 months. The local control (LC) rate was 76.8%, and the 1- and 2-year OS rates were 70.7% and 46.1%, respectively. The cut-off values of NLR and PLR were 3.16 and 201.33, respectively. Multivariate analysis identified the NLR cut-off value as a potential independent indicator of inferior OS [P=0.005, HR =3.317 (95% CI, 1.433–7.678)]. Biological effective dose (BED) was also associated with OS (P=0.035, HR =0.984 (95% CI, 0.969–0.999)]. CONCLUSIONS: NLR showed a strong association with LC and OS, which could serve as a predictive guide in the treatment of liver metastasis with SRBT. BED is also an independent factor affecting OS.