Prognostic significance of increased preoperative red cell distribution width (RDW) and changes in RDW for colorectal cancer

BACKGROUND: Increased preoperative red cell distribution width (RDW) is associated with poor prognosis in several cancers, but the relationships between preoperative RDW and changes in RDW (ΔRDW) and colorectal cancer (CRC) prognosis remain unclear. Our study aimed to demonstrate the prognostic significance of increased preoperative RDW and ΔRDW for CRC. METHODS: In this retrospective analysis, we enrolled 833 patients who underwent CRC surgery between 2015 and 2019 at the Affiliated Hospital of Xuzhou Medical University, China. ΔRDW in our study was defined as RDW at 1 month after discharge minus preoperative RDW. According to receiver operating characteristic (ROC) curve analysis, we used cut‐off values of 13.5% for RDW, 0.9% for ΔRDW. The cumulative survival rate was determined using the Kaplan–Meier method, and significant differences were evaluated by the log‐rank test. Multivariable Cox regression model was applied to clarify the independent risk factors for overall survival (OS), which were used to construct a nomogram prediction model. The competing risk method was also applied, and we analyzed only patients with early‐stage disease (stage 0‐II) for sensitivity analysis. RESULTS: Multivariable Cox regression analysis demonstrated that age, RDW, ΔRDW, postoperative adjuvant chemotherapy, CEA, CA19‐9, ASA, TNM stage, and pathological type were independent factors for OS in CRC patients (all p < 0.05). These prognostic factors were used to establish and verify the OS nomogram. Poorer OS was linked to higher RDW (HR = 1.52; 95% CI, 1.11–2.08; p < 0.01) and ΔRDW (HR = 1.65; 95% CI, 1.19–2.28; p < 0.01) in all‐stage patients, and was only linked to higher RDW in early‐stage patients. In competing risk model, H‐RDW and H‐ΔRDW were confirmed to be independent risk factors for CSS in CRC patients. CONCLUSIONS: High preoperative RDW and ΔRDW are both risk factors for OS and CSS in CRC.