The Role of Nutritional and Inflammatory Indices in Predicting Prognosis in Older Adults Undergoing Radiotherapy for Lung Cancer: NIRT-LC Study

Background/Objectives: The aim of this study was to identify which pre-radiotherapy (RT) immunonutritional indices best predict mortality and overall survival in geriatric patients with lung cancer (LC). Methods: This retrospective single-center study included LC patients aged ≥ 65 years who underwent RT between August 2020 and December 2024. Clinical records and laboratory data obtained within 14 days before RT were used to calculate immunonutritional indices. Survival and subgroup analyses evaluated prognostic significance. Results: Among the 174 patients included in the study, the median age was 69 years, and the median follow-up after RT was 8 months. Inflammatory indices were higher among non-survivors, whereas nutritional indices were lower (all p < 0.05). The ROC curve analyses identified the Prognostic Nutritional Index (PNI), Geriatric Nutritional Risk Index (GNRI), and CALLY (CRP–Albumin–Lymphocyte Index) as the strongest predictors of mortality (AUCs > 0.700). In adjusted Cox models, CALLY (HR = 0.652), PNI (HR = 0.939), and GNRI (HR = 0.950) were independently associated with reduced mortality risk. Conclusions: In older adults with LC undergoing RT, pre-treatment immunonutritional indices were independently associated with overall survival. Lower inflammatory burden and higher nutritional scores were linked to improved outcomes. These indices were associated with mortality before RT across LC types, independent of disease stage. Among them, CALLY, PNI, and GNRI showed the strongest associations with mortality, suggesting that these markers may be promising candidates for pre-RT risk assessment. However, further validation in prospective cohorts is required before routine clinical implementation.