title: Primary tumor location is an important predictive factor for wild-type KRAS metastatic colon cancer treated with cetuximab as front-line bio-therapy.
abstract: BACKGROUND
  Left- and right-sided colon cancers were significantly different in epidemiologic, clinical and histological parameters. However, the impact of primary tumor location in metastatic colon cancer treated with front-line targeted triplet regimens is unclear, particularly in Asian populations.
  
  
  METHODS
  A total of 121 patients with KRAS exon 2 codon 12/13 wild-type metastatic colon cancer were enrolled between January 2007 and December 2013. All patients received one target agent, such as cetuximab or bevacizumab, as a front-line targeted triplet regimen. The impact of primary tumor location for cetuximab and bevacizumab groups was analyzed, respectively.
  
  
  RESULTS
  In cetuximab group, left-sided metastatic colon cancer was superior to right-sided metastatic colon cancer in objective response rate (70.1% vs 33.3%, P = 0.024), progression-free survival (15.0 vs 5.3 months, P < 0.001) and overall survival (35.8 vs 14.4 months, P = 0.031). Primary tumor location was an independent prognostic factor for progression-free survival (hazard ratio 0.240, 95% confidence interval 0.114-0.508, P < 0.001). However, in the bevacizumab group, there were no differences in outcomes for either side. Primary tumor location was insignificant for progression-free survival and overall survival in univariate analysis.
  
  
  CONCLUSIONS
  Left-sided primary tumors were favored in cetuximab-based front-line targeted triplet regimen for metastatic colon cancer.
authors.affiliation: Division of Hematology and Oncology, Show Chwan Memorial Hospital, Changhua, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.|Program in Molecular Medicine, School of Life Sciences, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Hsueh-Ju
authors.initials: HJ
authors.lastname: Lu
authors.affiliation: Division of Colon and Rectum Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Jen-Kou
authors.initials: JK
authors.lastname: Lin
authors.affiliation: Division of Colon and Rectum Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Wei-Shone
authors.initials: WS
authors.lastname: Chen
authors.affiliation: Division of Colon and Rectum Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Jeng-Kai
authors.initials: JK
authors.lastname: Jiang
authors.affiliation: Division of Colon and Rectum Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Shung-Haur
authors.initials: SH
authors.lastname: Yang
authors.affiliation: Division of Colon and Rectum Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yuan-Tzu
authors.initials: YT
authors.lastname: Lan
authors.affiliation: Division of Colon and Rectum Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Division of Colon and Rectum Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Shih-Ching
authors.initials: SC
authors.lastname: Chang
authors.affiliation: Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan.|Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.|School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Hao-Wei
authors.initials: HW
authors.lastname: Teng
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000068258:Bevacizumab / Q000627:therapeutic use; D016022:Case-Control Studies; D000068818:Cetuximab / Q000627:therapeutic use*; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D012189:Retrospective Studies
chemical_list: D000970:Antineoplastic Agents; C117307:KRAS protein, human; D000068258:Bevacizumab; D016283:Proto-Oncogene Proteins p21(ras); D000068818:Cetuximab
keywords: KRAS wild-type; cetuximab; metastatic colon cancer; primary tumor location