Insulin-like growth factor (IGF) system is related to cell proliferation and tumor growth. We tested whether pretreatment plasma levels of IGF-1, IGF-2, and IGF binding protein (IGFBP)-3 would predict the prognosis in patients with advanced non-small cell lung cancer (NSCLC).

Plasma levels of IGF-1, IGF-2, and IGFBP-3 were measured using enzyme-linked immunoassays from 77 patients with advanced NSCLC enrolled in a phase II study of irinotecan plus cisplatin chemotherapy.

IGF-2 and IGFBP-3 levels were elevated in female patients, non-squamous cell carcinoma, and never smokers. In a univariate Cox proportional hazards model, higher levels of IGF-1, IGF-2, and IGFBP-3 were predictive of longer progression-free (P=0.001, 0.006, and 0.007, respectively) and overall survival (P=0.025, <0.0001, and 0.001, respectively). Multivariate analysis revealed that IGF-1 and IGFBP-3 are independent factors for progression-free survival (P<0.0001 and P=0.001, respectively). In addition, IGF-1, IGF-2, and IGFBP-3 are independently predictive for overall survival (P=0.004, 0.001, and 0.043, respectively).

High plasma levels of IGF-1, IGF-2, and IGFBP-3 were associated with good prognosis in patients with advanced NSCLC. Further validation of these results is needed to determine the prognostic significance of IGF system in advanced NSCLC.