Effects of tumor characteristics and immunonutritional indices on survival in patients treated for breast cancer in our clinic

Objective: This study aimed to evaluate the effects of classical clinicopathological factors and immunonutritional indices (PNI and SII) on overall survival (OS) and progression-free survival (PFS) in 720 patients with breast cancer. Materials and Methods: İn this retrospective study, clinical, pathological, treatment-related, and laboratory data of 720 patients treated between 2010 and 2023 were analyzed. The effects of age, tumor grade, T/N stage, LVI, ECE, molecular subtype, Ki-67, oligometastatic status, PNI, and SII on OS and PFS were assessed using Kaplan–Meier analysis, log-rank tests, and Cox regression models. Cut-off values for PNI and SII were determined using ROC analysis. Results: Both classical clinicopathological variables and immunonutritional indices were found to influence survival outcomes in breast cancer. Age, tumor grade, T and N stage, molecular subtype, Ki-67, LVI, ECE, oligometastasis, and overall stage were significantly associated with OS and PFS. Among the immunonutritional indices, PNI emerged as an independent prognostic factor for both OS and PFS, whereas SII was independently associated with progression risk. Kaplan–Meier and ROC analyses demonstrated that these indices provided meaningful discriminatory value for survival outcomes. Conclusion: This study confirms the strong prognostic impact of established clinicopathological factors in breast cancer while demonstrating that PNI and SII serve as easily applicable biomarkers with additional prognostic value. The independent effects of PNI on both OS and PFS, and of SII particularly on PFS, suggest that these indices may be integrated into baseline risk assessment in clinical practice. Keywords: Breast cancer; Radiotherapy; Tumor-related prognostic factors; Immunonutritional indices