Use of VEGF expression to predict for first-line treatment chemotherapy regimen in metastatic colorectal cancer.

Abstract

e14695 Background: In metastatic colorectal cancer treatment more successful results are achieved by adding anti-angiogenic therapy to the chemotherapy. Over expression of VEGF in colorectal cancer is known to be a poor prognosis factor but its effects on designating the therapy is not clear. In this study, results of the patients receiving FOLFIRI + Bevacizumab or XELOX + Bevacizumab were compared for VEGF expression. Methods: VEGF was assessed immunohistochemically in primary tumors of the 53 metastatic colorectal cancers. Severity and conformity of VEGF expression was evaluated. Results were used to assess the association with the therapy response, progression free survival (PFS) and overall survival (OS). Results: The median age of the patients was 55 (range, 32-79). In combination with bevacizumab 38 patients received FOLFIRI and 15 patients received XELOX. In 30 patients (57%) there was a strong expression of VEGF and in 23 patients (23%) the expression was weak. In the high VEGF expression group, PFS was 11 months in FOLFIRI receiving patients and 8 months in XELOX receiving ones but in low expression group PFS was 8 months in patients receiving either one of the two treatment protocols. In high expression group, PFS in FOLFIRI-bevacizumab combination receiving patients was different and this difference was statistically significant (p=0.009). Overall survival in FOLFIRI receiving patients with high VEGF expression was 26 months and with low VEGF expression it was 16 months (p=0.04). Median OS was not reached in the XELOX receiving patient group. FOLFIRI regime clinical benefit was 58% in high VEGF expression group whilst it was 34% in low expression group. This difference was not statistically significant but it was close to the significance threshold (p=0.06). There was no association between the therapy responses and VEGF expression of the 15 patients who received XELOX. Conclusions: There is no difference in efficacy between the first line chemotherapy regimens of the metastatic colorectal cancer. In this study, in metastatic colorectal patients with over expressed VEGF first line FOLFIRI-bevacizumab combination led to better response and survival rates.