Bilirubin Can Be Used as a Prognostic Factor for Lung Adenocarcinoma Patients with EGFR Mutations

Non-small cell lung cancer (NSCLC) patients with an epidermal growth factor receptor (EGFR) mutation demonstrate only a median progression-free survival (PFS) of 8 to 10 months and undergo EGFR tyrosine kinase inhibitors (EGFR-TKIs) therapy. For decades, bilirubin has been reported to be associated with the onset and prognosis of lung cancer as a prooxidant. This study aimed to investigate the prediction of pretreatment circulating bilirubin for PFS in lung adenocarcinoma (LAC) patients who underwent EGFR-TKIs targeted therapy.

LAC cases diagnosed and undergone EGFR-TKIs targeted therapy at The First Affiliated Hospital of Zhengzhou University between 2013 and 2015 were retrospectively reviewed. A total of 180 patients were studied according to inclusion and exclusion criteria. Follow-up data were collected for all patients until the disease progressed.

Univariate analysis showed that the levels of pretreatment total bilirubin (TBIL), indirect bilirubin (IBIL) and direct bilirubin (DBIL) were related to PFS (all p<0.05). Considering the close relationship among the three factors, we combined TBIL, IBIL and DBIL into one total factor, which is called bilirubin. Kaplan-Meier survival curves and Log rank tests indicated that patients with lower bilirubin levels had a shorter median PFS than those with higher bilirubin levels (8 vs. 15 months; p=0.002). Multivariate analysis demonstrated that pretreatment bilirubin is an independent prognostic factor (HR=0.454, CI: 0.267-0.773, p=0.004).

This study confirms that bilirubin can predict the prognosis of LAC patients who had undergone EGFR-TKIs targeted therapy.