Preoperative systemic immune-inflammation index and prognostic nutritional index predict prognosis of patients with pulmonary neuroendocrine tumors after surgical resection.

Background: Pulmonary neuroendocrine tumors (PNETs) are a special subtype of lung cancer with treatment methods are limited and prognostic indicators are insufficient. The preoperative systemic immune-inflammation index (SII) and prognostic nutritional index (PNI) are effective tumor biomarkers that have important significance for the prognosis of many malignant tumors. However, there is no similar research on the predictive value of SII and PNI for operable PNETs. Our study aimed to clarify the predictive value of SII and PNI in PNETs patients after surgical resection. Methods: This study retrospectively analysed the relevant clinical data of PNETs patients who received surgical treatment from 2005 to 2015, which was obtained from patient's clinical records, blood test results recorded on admission before surgical treatment, and follow-up by hospital records. Results: A total of 381 PNETs patients were enrolled in this study. Preoperative PNI was associated with age (P=0.001), T stage (P=0.001), tumor length (P=0.002), drinking status (P=0.013) and smoking status (P=0.049), while SII was significantly associated with T stage (P=0.001), tumor length (P=0.001) and TNM stage (P=0.001). There was significant difference between high SII and low PNI and worse OS of PENTs (P=0.001 and P<0.001). SII (P=0.002), neutrophil/lymphocyte ratio (NLR) (P<0.001), platelet/lymphocyte ratio (PLR) (P=0.001), lymph node metastasis (P<0.001), operation time (P=0.034<0.05), treatment (P<0.001) and PNI (P=0.044<0.05) were independent prognostic factors for PNETs identified by multivariate Cox regression analysis. Conclusions: High SII and low PNI indicated poor prognosis of patients with PNETs. Both of SII and PNI can predict the prognosis of PNETs and stratify patients for better treatment.