Serum Ferritin as a Prognostic Biomarker for Survival in Relapsed or Refractory Metastatic Colorectal Cancer

Background: This study investigated the prognostic impact of serum ferritin for survival in patients with relapsed or refractory metastatic colorectal cancer (mCRC). Methods: This retrospective cohort study reviewed clinicopathological characteristics and laboratory biomarkers in 120 mCRC patients being treated with Korean Medicine (KM). The overall survival (OS) of patients was calculated using the Kaplan-Meier method, and statistical significance was assessed using the log-rank test. Univariate and multivariate analyses of Cox proportional hazards regression were used to evaluate the prognostic impact for survival in relapsed or refractory mCRC patients. Results: Of the patients, 62.5% had liver metastases, 74.1% underwent greater than second-line chemotherapy, and 80.8% underwent surgery. Median OS was 7.6 months for all patients after the initiation of KM treatment, which was begun 13.7 months, on average, after mCRC diagnosis. Concerning prognostic factors such as the presence of liver metastasis (p = 0.024), high carcinoembryonic antigen level (CEA > 5 ng/mL, p = 0.044), elevated C-reactive protein (CRP ≥ 10.0 mg/L, p = 0.000), high absolute monocyte count (AMC > 413.3 cells/μL, p = 0.034), elevated serum ferritin (ferritin ≥ 150 ng/mL, p = 0.002), low hemoglobin level (Hb < 12 g/dL, p = 0.026) and low albumin (albumin < 3.5 g/dL, p = 0.003) were associated with increased hazard ratios and poor survival. According to the multivariate proportional hazards model with backward and forward manners, albumin (albumin < 3.5 g/dL; hazard ratio (HR) 2.218, 95% confidence interval (CI) 1.135 - 3.990, p = 0.019), CRP (CRP ≥ 10.0 mg/L; HR 2.506, 95% CI 1.644 - 3.822, p = 0.000), CEA (CEA > 5 ng/mL; HR 2.040, 95% CI 1.203 - 3.460, p = 0.008), and serum ferritin (ferritin ≥ 150 ng/mL; HR 1.763, 95% CI 1.169 - 2.660, p = 0.007) were independent prognostic biomarkers of survival in mCRC patients. Conclusions: These results indicate that serum ferritin acts as an independent prognostic biomarker for survival in relapsed or refractory mCRC patients.