Using the combined C-reactive protein and controlling nutritional status index for elderly non-small cell lung cancer.

Background: We found that conventional controlling nutritional status (CONUT) score can serve as a sensitive prognostic marker. Some prognostic indicators do include C-reactive protein (CRP), such as the CRP-lymphocyte ratio (CLR), CRP-albumin-lymphocyte index (CALLY), and CRP-albumin ratio (CAR). However, CRP has not been combined with the CONUT score, which we believe could result in a more sensitive marker. This study evaluated the combined use of the CONUT score and CRP to predict prognostic outcomes in elderly non-small cell lung cancer (NSCLC) patients undergoing surgical resection.

Methods: This study involved the retrospective analysis of 114 NSCLC patients who were over 80 years old and underwent curative resection. The summation of the CRP score and CONUT score was defined as the combined CRP and controlling nutritional status (C-CONUT) score. The capacity of CRP, CONUT score, and C-CONUT score to predict overall survival (OS) was evaluated via receiver operating characteristics (ROC) curves. Prognostic markers for OS were then identified using the Cox proportional hazards regression model.

Results: The ROC curves identified the C-CONUT score as the most reliable marker of prognosis (area under the curve =0.745). Forty-seven patients were included in the high C-CONUT (≥3) group, while 67 patients were included in the low C-CONUT (0 to 2) group. Worse prognosis rates were observed in the high C-CONUT group in comparison to the low C-CONUT group in terms of OS (five-year OS: 39.8% versus 87.4%, P<0.001). Lymphatic invasion (P<0.001), histological findings (P=0.02), and C-CONUT score [hazard ratio (HR): 5.07, 95% confidence interval (CI): 2.39-10.8, P<0.001] were identified as exclusive markers for OS prognosis in the multivariate analysis.

Conclusions: Our current findings indicate that C-CONUT score may serve as an innovative prognostic marker in the elderly NSCLC population.