Pretreatment albumin-to-globulin ratio as a predictive marker for tyrosine kinase inhibitor in non-small cell lung cancer.

BACKGROUND: A low albumin-to-globulin ratio (AGR) has been known as a prognostic factor for cancer-related mortality. However, no study has elucidated its usefulness as a predictive factor in the era of targeted therapy, and so, we evaluated this in the present study. METHODS: We retrospectively analyzed 2012 non-small cell lung cancer (NSCLC) patients treated with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). Among these patients, 645 patients who had EGFR mutation and suitable pretreatment laboratory values were included. AGR was calculated 2 months before treatment and 4 months after treatment in each patient. The optimal cutoff value of AGR, and progression free survival (PFS) were also determined. RESULTS: The optimal cutoff value of AGR was 1.17, which yielded a highest HR of 1.89 (P < 0.001) for poor PFS. The median PFS was 9.5 months (95% confidential interval [CI] 7.0-10.4) in patients with pretreatment AGR < 1.17 and 13.5 months (95% CI 11.9-14.7) in those with pretreatment AGR >= 1.17. Pretreatment AGR showed an independent predictive value (adjusted HR 1.80, P < 0.001) when age, performance status, and pre-TKI systemic treatment was adjusted for. CONCLUSIONS: We suggest that patients with NSCLC with EGFR mutations who have AGR values lower than 1.17 at the beginning of EGFR TKI treatment should be considered to have a high risk of early EGFR TKI failure.