ORIGINAL ARTICLE – THORACIC ONCOLOGY Risk Stratification According to the Prognostic Nutritional Index for Predicting Postoperative Complications After Lung Cancer Surgery Satoru Okada, MD 1 , Junichi Shimada, MD, PhD 1 , Satoshi Teramukai, PhD 2 , Daishiro Kato, MD, PhD 1 , Hiroaki Tsunezuka, MD, PhD 1 , Naoko Miyata, MD 1 , Shunta Ishihara, MD 1 , Tatsuo Furuya, MD 1 , Chiaki Nakazono, MD 1 , Narumi Ishikawa, MD 1 , and Masayoshi Inoue, MD, PhD 1 1 Division of Thoracic Surgery, Department of Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan; 2 Department of Biostatistics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan ABSTRACT Background. The prognostic nutritional index (PNI), an immune nutritional marker based on serum albumin levels and total lymphocyte count, predicts postoperative com- plications in various types of malignancies. However, the clinical significance of the PNI for postoperative compli- cations following lung cancer surgery is uncertain. Methods. Patients with resected non-small cell lung can- cer (n = 515) were retrospectively analyzed and the relationship between the preoperative PNI and postopera- tive complications was evaluated. Results. Multivariate logistic regression analysis revealed that a preoperative low PNI was a significant independent predictor of postoperative complications of Clavien–Dindo Grade C II (odds ratio: 1.06 per unit decrease, 95.0% confidence interval 1.01–1.11). Patients were divided into three groups according to the preoperative PNI: normal (C 50; n = 324), mildly low ( \ 50, C 45; n = 134), and severely low ( \ 45; n = 57). The incidence of postopera- tive complications of Grade C II and Grade C III in the normal, mildly low, and severely low PNI groups was 22.2, 39.6, and 42.1% and 7.1, 16.4, and 22.8%, respectively. The incidence of postoperative complications of Grade - C II and Grade C III was significantly higher in the mildly low and severely low PNI groups than in the normal PNI group (p \ 0.001 and p \ 0.001, respectively). The inci- dence of air leak, pneumonia, and extrapulmonary infection, but not arrhythmia, was significantly higher in the mildly low and severely low PNI groups than in the normal PNI group. Conclusions. The PNI could be a useful marker to predict the risk of postoperative complications after lung cancer surgery. Lung cancer is a leading cause of cancer-related deaths worldwide. 1 For lung cancer patients, postoperative com- plications after pulmonary resection may prolong the postoperative hospital stay and incur greater medical expenses. 2 For thoracic surgeons, it would be useful to have better preoperative parameters so that patients likely to have poor postoperative outcomes may be identified before surgery. Several predictive factors of postoperative complica- tions after pulmonary resection have been identified, including age, sex, smoking status, percent predicted forced expiratory volume in 1 s (FEV1), chronic obstruc- tive pulmonary disease (COPD), body mass index (BMI), advanced-stage disease, surgical approach (i.e., thoraco- tomy or video-assisted thoracoscopic surgery), mode of pulmonary resection, operative time, and B-type natriuretic peptide level. 3–11 The nutritional and immunological status of patients has been reported to influence postoperative outcomes. The prognostic nutritional index (PNI) proposed by Onodera et al. is calculated based on the serum albumin level and peripheral lymphocyte count. 12 The PNI represents an Ó Society of Surgical Oncology 2018 First Received: 24 October 2017 M. Inoue, MD, PhD e-mail: mainoue@koto.kpu-m.ac.jp Ann Surg Oncol https://doi.org/10.1245/s10434-018-6368-y