Postoperative prognostic nutrition index predicts survival in patients with small bowel adenocarcinoma after surgical resection

Background: Surgical resection (SR) is the main treatment for small bowel adenocarcinoma (SBA), but it increases metabolic demand, systemic inflammation, and digestive dysfunction, resulting in major impacts on the postoperative outcomes of patients. In this study, we aimed to investigate the role of the postoperative prognostic nutritional index (PNI), a surrogate marker of inflammation and nutrition, in patients with SBA after resection. Methods: From June 2014 to March 2022, 44 consecutive patients who underwent SR for SBA in Taipei Veterans General Hospital were retrospectively reviewed. Factors associated with survival including PNI were analyzed. Results: PNI decreased in patients after SR for SBA (median change: −1.82), particularly in those who underwent Whipple operation or developed postoperative pancreatic fistula. Postoperative PNI <45.2 best predicted overall survival (OS) (area under the receiver operating characteristic curve [AUROC]: 0.826, p = 0.001). Patients with lower postoperative PNI had significantly worse OS compared to those with higher postoperative values (median OS: 19.3 months vs not reached, p < 0.001). Low postoperative PNI (hazard ratio [HR]: 11.404, p = 0.002), tumoral lymphovascular invasion (HR: 8.023, p = 0.012), and adjuvant chemotherapy (HR: 0.055, p = 0.002) were independent risk factors for OS. Postoperative PNI also significantly predicted recurrence-free survival independent of lymphovascular invasion and adjuvant chemotherapy (HR: 6.705, p = 0.001). Conclusion: PNI commonly decreases in patients with SBA who undergo Whipple surgery or develop postoperative pancreatic fistula. Postoperative PNI independently predicts survival and may serve as a clinical marker to optimize patient outcomes.