Preoperative iron status is a prognosis factor for stage II and III colorectal cancer.

Iron deficiency anemia is represented in colorectal cancer (CRC) patients. Iron surplus load to increase non-transferrin bound iron (NTBI), and NTBI promotes cancer progression and influences microbiota. This study investigated whether preoperative serum iron status was associated with prognosis after CRC resection. We evaluated preoperative iron and transferrin saturation (TSAT), which was calculated as iron divided by total iron-binding capacity, in 327 patients who underwent surgery for Stage II–III CRC. Fe   40% were defined as low and high iron, respectively. The associations between iron status and overall survival (OS) were evaluated in univariate and multivariate Cox proportional hazards analysis. Of the 327 patients, 179 (54.7%), 124 (37.9%) and 24 (7.3%) had low, normal and high iron, respectively. In univariate analysis, low iron was associated with shorter OS (hazard ratio [HR] 2.821, 95% confidence interval [CI] 1.451–5.485, P = 0.002). High iron was also associated with shorter OS (HR 3.396, 95% CI 1.359–8.489, P = 0.009). In multivariate analysis, high age (P = 0.002), depth of invasion pT4 (P = 0.012), lymph-node metastasis presence (P = 0.035), low albumin (P = 0.011), low iron (HR 2.282, 95% CI 1.163–4.478, P = 0.016) and high iron (HR 3.757, 95% CI 1.486–9.494 P = 0.005) were independently associated with shorter OS. High iron was associated with the amount of intratumoral Fusobacterium nucleatum compared with normal iron. Both low and high preoperative iron in Stage II–III CRC patients were associated with unfavorable OS in univariate and multivariate analyses.