Correlation of the controlling nutritional status score and the prognostic nutritional index with the prognosis of patients treated with radiotherapy for small-cell lung cancer

Background: We aimed to explore the associations between the controlling nutritional status (CONUT), the prognostic nutritional index (PNI), and prognostic outcomes in patients with small-cell lung cancer (SCLC) receiving radiotherapy. Methods: A total of 93 SCLC patients who received radiotherapy at the hematology department in the First Affiliated Hospital of Hainan Medical University were retrospectively included in this analysis. Patient CONUT and PNI values were calculated. Receiver operating characteristic (ROC) curves were utilized to determine the optimal cut-off, the area under the curve (AUC), sensitivity, and specificity of CONUT and PNI in discriminating patient outcomes. Kaplan-Meier curve analysis was performed, and overall survival (OS) was compared for patients with CONUT >3 and <= 3, or those with PNI >47.7 and <= 47.7. Univariate and multivariate analysis using the Cox proportional hazard model was performed to identify the risk factors for patient death. Results: The AUCs for CONUT and PNI were 0.95 and 0.82, respectively. The CONUT results indicated that patient OS decreased significantly from normal to mildly malnourished. Meanwhile, the OS for moderately malnourished patient decreased to severely malnourished (P for trend <0.001). Patients with CONUT >3 or PNI <= 47.7 had significantly shorter OS than those with CONUT <= 3 (median survival time 12 vs. 23 months; P<0.001) or with PNI >47.7 (median survival time 20 vs. 15 months; P=0.010). Multivariate analysis indicated that the TNM stage [hazard ratio (HR) =1.21; 95% confidence interval (CI): 1.03-1.66], CONUT score (HR =2.33; 95% CI: 1.76-3.91), and PNI <= 47.7 (HR =1.33; 95% CI: 1.09-1.99) were independent prognostic indicators for patient death. Conclusions: The CONUT and PNI were potential indicators for the outcome of patients with SCLC. CONUT >3 or PNI <= 47.7 indicated an unfavorable prognosis for SCLC patients.