Association of the prognostic nutrition index with overall survival time of the patients with brain metastases of lung adenocarcinoma

Abstract

Objective To explore the effect of prognostic nutrition index (PNI) on the overall survival time of patients with brain metastases of lung adenocarcinoma. Methods A retrospective analysis was performed on the clinic data of 274 patients who were admitted to our hospital and confirmed with brain metastases of lung adenocarcinoma from May 2013 to May 2016. The prognosic factors for brain metastases such as PNI, gender, age, smoking history, epidermal growth factor receptor (EGFR) mutation status, Karnofsky performance status (KPS) score, the number of brain lesions, treatment of brain lesions, extracranial metastases and the status of primary disease were analyzed. The receiver operating characteristic (ROC) curve was drawn to determine the optimal cut-off value of PNI, and the patients were divided into high PNI group and low PNI group. The univariate and multivariate prognostic analyses were performed by the Log-rank test and the Cox proportional hazards model. Results The patients were divided into high PNI (>50.45) group (n=72) and low PNI (≤50.45) group (n=202). The median overall survival (OS) was 11.20 months in all patients with brain metastases, and the median OS of the low PNI group and high PNI group were 10.13 months and 15.17 months respectively. The univariate analysis results showed that gender (χ2=5.459, P=0.019), age (χ2=3.986, P=0.046), smoking or not (χ2=6.878, P=0.009), EGFR mutation status (χ2=20.484, P<0.001), KPS score (χ2=126.573, P<0.001), extracranial metastases or not (χ2=4.403, P=0.036), treatment on the brain lesions (χ2=40.444, P<0.001) and PNI (χ2=7.972, P=0.005) were related to the prognosis. The Cox multivariate analysis results showed that age (HR=1.580, 95%CI: 1.104-2.295, P=0.012), EGFR mutation status (HR=0.549, 95%CI: 0.408-0.738, P<0.001), KPS score (HR=0.077, 95%CI: 0.045-0.134, P<0.001), treatment on brain metastases (HR=0.882, 95%CI: 0.789-0.987, P=0.029) and PNI (HR=0.614, 95%CI: 0.437-0.861, P=0.005) were related to the prognosis. Conclusion PNI is an independent prognostic predictor of brain metastases in patients with lung adenocarcinoma, and the high-PNI is correlated to the long OS of patients with brain metastases of lung adenocarcinoma, which has certain clinical practical value. Key words: Carcinoma, non-small-cell lung; Neoplasm metastasis, brain; Nutrition assessment; Prognosis