IL-8 and thrombospondin-1 as prognostic markers in patients with metastatic colorectal cancer receiving bevacizumab

PURPOSE: Bevacizumab (B) plus chemotherapy (CT) is a common choice for first-line treatment of metastatic colorectal cancer. Molecular predictors of B efficacy have still not been identified. We analyzed the role of 22 angiogenesis-associated proteins in patient outcome. PATIENTS AND METHODS: Serum samples collected at baseline and at the first clinical evaluation were available for 58 patients enrolled in the randomized multicenter ITACa trial and who received CT+ B. Serum protein levels were determined using multiplex ELISA. RESULTS: Patients with baseline ≥145 pg/mL IL-8 showed shorter median progression-free survival and overall survival (OS) than those with lower levels (6.5 vs 6. 12.6 months; HR 7.39, P<0.0001 and 8.7 vs 28.8 months, HR 7.68, P<0.001, respectively). Moreover, patients with baseline thrombospondin-1 levels ≥12,000 ng/mL had a better median OS than those with lower levels (34.5 vs 13.1 months, HR 0.43, P=0.007). Patients with a ≥20% reduction in IL-8 levels from baseline to first clinical evaluation showed a better progression-free survival and OS than the others (HR 0.41, P=0.005 and HR 0.43, P=0.007, respectively). CONCLUSION: Baseline IL-8 and thrombospondin-1 levels and reduced IL-8 during B treatment could represent potential prognostic markers in metastatic colorectal cancer.