Serum bilirubin level predicts postoperative overall survival in oral squamous cell carcinoma

BACKGROUND Aberrant level of serum bilirubin, marker of hepatobiliary and hematological disorders, was associated with patient prognosis in several human malignancies. In this study, we aim to evaluate the predictive value of serum bilirubin for clinicopathologic characteristics and survival of patients with oral squamous cell carcinoma (OSCC). METHODS This study retrospectively reviewed 129 patients with OSCC and 129 normal controls matched for age and sex. The association between levels of preoperative direct bilirubin (DBIL), indirect bilirubin (IBIL), total bilirubin (TBIL), and clinical variables was analyzed. A proportional hazards regression model was used to find out the independent predictors of survival. RESULTS Significantly lower TBIL (P = .009) and IBIL (P < .001) were found in OSCC patients compared with normal controls. DBIL (P = .011) and lymph-node metastasis (P = .031) were found to be independent prognostic factors. Patients with higher DBIL (≥4.0 μmol/L) had longer overall survival than those with lower DBIL (P = .002). Patients with both lymph-node metastasis and lower DBIL showed the shortest overall survival (P = .001). CONCLUSIONS Lower DBIL was associated with a poorer prognosis and may be regarded as an independent prognostic marker for patients with OSCC.