Survival outcome of bevacizumab followed by cetuximab in metastatic colorectal cancer patients.
529 Background: The molecular targeted agents, such as bevacizumab and cetuximab have been shown to improve overall survival of metastatic colorectal cancer (mCRC) patients. However, we still do not know what sequence is best to use the molecular targeted agents for mCRC especially in K-ras wild case. In this analysis, we evaluate the benefits of using bevacizumab followed by cetuximab for mCRC patients retrospectively. Methods: From July 2006 to September 2010, 60 chemotherapy-naive patients who were diagnosed as mCRC, received oxaliplatin based regimen for first line, did not respond to bevacizumab containing regimen used for first line or second line, and received cetuximab or continued bevacizumab, were eligible for this analysis. 28 patients received cetuximab as third line or fourth line chemotherapy due to K-ras wild type (Group A). And 32 patients continued bevacizumab-containing regimen in spite of disease progression (Group B). Results: The median number of cycles of bevacizumab containing regimen were 9 (range, 2-30) in group A and 8 (range, 2-27) in group B, and cetuximab 12(range, 3-32) in group A. The difference of the rate of serious adverse effects was not significant between two groups. Median overall survival was significantly higher in Group A than Group B (31.2 months (95%CI: 23.2-39.3 months) and 27.0 month (95%CI: 17.2-37.6), respectively) (P<0.001). Partial response rate of cetuximab was 18%(5/28) in group A. Median progression free survival of cetuximab in group A was 4.3 months (95%CI: 2.62- 6.06). Conclusions: Using cetuximab after progression with bevacizumab might be effective sequence to improve the overall survival of K-ras wild mCRC patients. But we need further prospective study to look for the best sequence in chemotherapy for mCRC patients.