Pretreatment comprehensive nutritional index predicts survival in locally advanced rectal cancer after neoadjuvant chemoradiotherapy and surgery

Nutritional status significantly influences treatment tolerance and long-term outcomes in patients with locally advanced rectal cancer (LARC); however, individual nutritional markers may not fully capture overall nutritional reserves. This study aimed to evaluate the prognostic value of a comprehensive nutritional index (CNI), derived from principal component analysis, in patients with LARC undergoing neoadjuvant chemoradiotherapy (NCRT) followed by surgical intervention. We conducted a retrospective analysis of 336 patients with LARC who received NCRT followed by surgery between 2014 and 2019. The CNI was constructed using body mass index, usual body weight percentage, total lymphocyte count, serum albumin, and hemoglobin levels. Patients were categorized into low- and high-CNI groups based on an outcome-oriented cut point, and survival outcomes were assessed through Kaplan-Meier analysis and Cox regression. Patients with lower CNI scores exhibited significantly poorer overall survival and disease-free survival compared to those with higher CNI scores. Furthermore, CNI remained independently associated with both endpoints after adjusting for established pathological factors, including tumor regression grade and ypN stage. A nomogram that integrates CNI, tumor regression grade, and ypN stage demonstrated favorable discrimination and calibration during internal validation. These findings support the use of pretreatment CNI as a practical nutritional composite associated with prognosis in LARC patients treated with NCRT, and the proposed nomogram may enhance individualized risk estimation.