Prognostic nutritional index before neoadjuvant therapy in patients with locally advanced rectal cancer

The impact of nutritional and inflammatory parameters on prognosis in malignancy patients has been a subject of extensive research. Among these parameters, lymphocyte, neutrophil, platelet, and C-reactive protein levels are most commonly used, often evaluated in conjunction with various formulas. The Prognostic Nutritional Index (PNI) is an effective measure reflecting both nutritional status and immune system function. It has been demonstrated that PNI holds prognostic value for various gastrointestinal cancers. This study aims to evaluate the relationship between PNI and survival in patients with locally advanced rectal cancer. Our study included 108 patients with locally advanced rectal cancer who were followed up at the Tokat Gaziosmanpaşa University Medical Oncology Clinic between January 2013 and January 2024. We assessed the patients' demographic, clinical, and pathological characteristics, treatments received, prognostic nutritional index, prognostic markers, and survival. The relationship between pre-neoadjuvant chemotherapy PNI values and 5-year overall survival and disease-free survival was analyzed. ROC analysis of PNI based on radiological response was performed, with a cutoff value calculated at 43.06. When patients were grouped by survival and the relationship between PNI and survival was examined, it was found that patients who had died had lower PNI indices. Specifically, among living patients, 63.3% (n=50) had low PNI and 36.7% (n=29) had high PNI, whereas among deceased patients, 75.9% (n=22) had low PNI and 24.1% (n=7) had high PNI. No statistically significant relationship between PNI and survival was found in this study. Our findings indicate that patients with low PNI have significantly lower survival rates. This result highlights PNI as a critical indicator in cancer prognosis and confirms its reliability as a prognostic tool in line with other studies in the literature. Keywords: Rectal cancer, locally advanced, prognostic nutritional index, overall survival, disease-free survival