Treatment Strategy For Metastatic Colorectal Cancer (Mcrc) Treated With Chemotherapy Plus Biological Targeted Agent: Is Strategy With Biological Targeted Agent Based On The Primary Tumor Lesion Possible?

769Background: The data from randomized trials suggested that primary tumor location (PTL) could represent a prognostic and predictive factor in mCRC patients, particularly during treatment with anti- EGFR therapy. However, it remains unclear whether anti-EGFR is effective for right- sided primary tumors (RT). Methods: Single-institution, retrospective, case-control study was reviewed. A total of 110 patients with mCRC were enrolled between January 2011 and December 2016. We evaluated the association between PTL and survival parameters in patients with previously untreated mCRC receiving first-line chemotherapy (FOLFOX/CapeOX or FOLFIRI/IRIS) plus cetuximab(Cmab) or bevacizumab(Bmab). The impact of PTL for Cmab and Bmab groups was analyzed, respectively. Results: 76 patients presented Left-sided primary tumors (LT) and 34 patients RT. Median PFS, median OS, and ORR were numerically superior in our study patients with LT compared with patients with RT (PFS, L vs R, 13.0 vs 6.8 M, p = 0.0040; OS, 36.2 vs 19...