Prognostic impact of immunonutritional status changes during preoperative chemoradiation in patients with rectal cancer

Purpose: Previous studies have demonstrated the prognostic impact of the prognostic nutritional index (PNI), a proposed indicator of immunonutritional statuses of surgical patients, on patients with various gastrointestinal cancers. Although the prognostic impact of the PNI on patients with colorectal cancer has been well established, its value has not been studied in patients treated with preoperative chemoradiation (pCRT). This study aimed to evaluate the prognostic impact of PNI on patients receiving pCRT for locally advanced rectal cancer (LARC). Methods: Patients with LARC who underwent curative pCRT followed by surgical resection were enrolled. The PNI was measured in all patients before and after pCRT, and the difference in values was calculated as the PNI difference (dPNI). Patients were classified according to dPNI (<5, 5-10, and >10). Clinicopathologic parameters and long-term oncologic outcomes were assessed according to dPNI classification. Results: No significant intergroup differences were observed in clinicopathologic parameters such as age, histologic grade, tumor location, tumor-node-metastasis stage, and postoperative complications. Approximately 53% of the patients had a mild dPNI (<5); only 15% had a high dPNI (>10). Univariate and multivariate analyses identified the dPNI as an independent prognostic factor for disease-free status (P < 0.01; hazard ratio [HR], 2.792; 95% confidence interval [CI], 1.577-4.942) and for cancer-specific survival (P = 0.012; HR, 2.469; 95%CI, 1.225-4.978). Conclusion: The dPNI is predictive of long-term outcomes in pCRT-treated patients with LARC. Further prospective studies should investigate whether immune-nutritional status correction during pCRT would improve oncologic outcomes.