BackgroundThe prognostic nutritional index (PNI) is a valuable marker for evaluating the nutritional status associated with postoperative complications and the prognosis of patients with cancer. However, the role and clinical value of PNI in infection after lung cancer surgery remains unclear. This study examined the association between PNI and infection after lobectomy for lung cancer, focusing on the predictive value of PNI. MethodsWe conducted this retrospective cohort study on 139 patients with non-small cell lung cancer (NSCLC) who underwent surgery between September 2013 and December 2018. Two groups were composed according to their PNI values (≥ 50 or <50 ), and the relationship was assessed with infection after lobectomy. ResultsOnly PNI values, atelectasis, and prolonged air leaks were significantly associated with the development of infection. The median preoperative PNI was 52.97±5.69. Postoperative infection was seen in patients (15.5%) with PNI≥ 50 and 38.1% in patients with PNI <50. The mean PNI in patients with postoperative infection, empyema, and prolonged air leakage was lower than in patients without these conditions. ConclusionsMalnutrition is commonly seen in patients with malignancy. The overall malnutrition rate is 45% in lung cancer patients. Patients with metastatic diseases are malnourished in a 73% ratio compared to 5% for localized diseases. Furthermore, malnutrition increases the tendency of postoperative infection and reduces wound healing. We aim to determine whether PNI can be a predictive index marker for postoperative infection in patients with NSCLC who underwent lobectomy. Postoperative infection was seen in 15.5% of patients with PNI>50 and 38.1% in patients with PNI <50.