Impact of the prognostic nutritional index on the recovery and long-term oncologic outcome of patients with colorectal cancer

Purpose: The prognostic nutritional index (PNI) has been reported to be a predictive marker for surgical outcomes and prognosis in gastrointestinal malignancies. In this study, we aimed to identify the impact of preoperative PNI on the recovery and long-term oncologic outcome of patients with colorectal cancer (CRC). Methods: A total of 3569 patients who underwent curative resection for CRC were enrolled, and their medical records were analyzed retrospectively. Preoperative PNI was calculated as 10× serum albumin concentration (g/dL) + 0.005 × total lymphocyte count (/mm³). The occurrence of postoperative complications, duration of hospital stay, disease-free survival, and overall survival were analyzed according to the preoperative PNI. In addition, PNI was compared according to the status of pathologic factors. Results: The postoperative complication rate and postoperative duration of hospital stay increased significantly as PNI increased. Patients with a lower PNI showed a worse survival outcome. Increased depth of tumor invasion, presence of distant metastasis, and poorer histologic grade were associated with a lower PNI. The cut-point of preoperative PNI was calculated as 50, and patients with PNI > 50 showed a markedly better survival outcome. Furthermore, patients with PNI > 50 showed better results in postoperative complication rate and postoperative duration of hospital stay. Conclusion: Preoperative PNI is a simple and efficient indicator (cut-point 50) for estimating the recovery and oncologic outcome of patients. A low PNI was associated with increased occurrence of postoperative complications, prolonged hospital stay, poor oncologic outcome, and aggressive tumor phenotypes.