Prognostic value of serum bilirubin in southern Chinese patients with advanced nasopharyngeal carcinoma.

Background: We evaluated the prognostic value of serum bilirubin in advanced nasopharyngeal carcinoma (NPC) patients.

Methods: Seven-hundred fifty-nine advanced NPC patients treated with definitive chemoradiotherapy were retrospectively analyzed. Serum indirect bilirubin (IBIL) and direct bilirubin (DBIL) were measured before treatment. To evaluate different cutoff points for serum bilirubin, we utilized ROC curves. The Kaplan-Meier method and log-rank test were adopted to calculate and compare survival outcomes. Cox proportional hazard models were used to perform univariate and multivariate analyses.

Results: At 5 y, IBIL >7.15 μmol/l were significantly associated with superior progression-free survival (PFS, 83.6% vs 70.3%; P < .001), overall survival (OS, 88.6% vs 80.5%; P = .012), distant metastasis-free survival (DMFS, 90.3% vs 82.8%; P = .006), and locoregional relapse-free survival (LRFS, 92.1% vs 86.4%; P = .048) than IBIL ≤7.15 μmol/l. Similarly, patients with DBIL >2.65 μmol/l had better prognosis across all outcomes than those of patients with DBIL ≤2.65 μmol/l (all P < .05), except no difference was observed in LRFS (90.5% vs. 87.3%, P = .195). Multivariate analyses showed that IBIL >7.15 μmol/l was an independent protective prognostic factor for PFS (HR, 0.57; 95% CI, 0.40-0.81; P = .002), OS (HR, 0.67; 95% CI, 0.43-0.92; P = .041), and DMFS (HR, 0.63; 95% CI, 0.40-0.98; P = .034); while serum DBIL only remained significant for PFS (HR, 0.63; 95% CI, 0.44-0.89; P = .009).

Conclusions: Pretreatment IBIL and DBIL are potentially independent prognostic factors for patients with advanced NPC.