title: Observational cohort study focused on treatment continuity of patients administered XELOX plus bevacizumab for previously untreated metastatic colorectal cancer.
abstract: BACKGROUND
  There has been remarkable progress in systemic chemotherapy for metastatic colorectal cancer due to the widespread use of irinotecan, oxaliplatin, anti-vascular endothelial growth factor antibody, and anti-epidermal growth factor receptor antibody. It is important to continue treatment with the optimal combination of these drugs and prolong progression-free survival (PFS) to improve overall survival (OS). We conducted a prospective observational cohort study of 40 patients treated with XELOX plus bevacizumab for previously untreated metastatic colorectal cancer to investigate treatment continuity.
  
  
  METHODS
  Eligibility criteria were as follows: 1) histologically confirmed metastatic colorectal cancer; 2) lesions evaluable by imaging; 3) previously untreated; 4) suitable condition to receive XELOX plus bevacizumab; and 5) written informed consent. Outcomes were treatment continuity, overall response rate, resection rate, liver resection rate, time to treatment failure, PFS, and OS. Forty patients were enrolled and followed up for 2 years.
  
  
  RESULTS
  Between July 2010 and June 2012, 40 patients were enrolled. The median number of treatment cycles was 7.5, and the reasons for discontinuation of treatment were as follows: complete response (five patients), resection (ten patients), progression (15 patients), adverse events (seven patients), and patient refusal (three patients). The overall response rate was 57.5%, resection rate was 25%, and liver resection rate was 15%. After a median follow-up of 31.4 months, the median time to treatment failure, PFS, and OS were 5.3, 13.3, and 38.9 months, respectively.
  
  
  CONCLUSIONS
  Although the median time to treatment failure was 5.3 months, the median PFS and OS were prolonged to 13.3 and 38.9 months, respectively. This may have resulted from the chemotherapy-free interval due to complete response in five patients and resection in ten patients.
authors.affiliation: Gastrointestinal Cancer Center, Sano Hospital, Kobe, Hyogo.
authors.forename: Masahito
authors.initials: M
authors.lastname: Kotaka
authors.affiliation: Department of Surgery, Kohka Public Hospital, Koka, Shiga.
authors.forename: Fusao
authors.initials: F
authors.lastname: Ikeda
authors.affiliation: Department of Colorectal Surgery, Sakai City Medical Center, Sakai, Osaka.
authors.forename: Masaki
authors.initials: M
authors.lastname: Tsujie
authors.affiliation: Department of Surgery, Hyogo Prefectural Nishinomiya Hospital, Nishinomiya, Hyogo.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yoshioka
authors.affiliation: Department of Surgery, Seikei-kai Chiba Medical Center, Chiba, Chiba.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nakamoto
authors.affiliation: Department of Surgery, Kobe-Ekisaikai Hospital, Kobe, Hyogo.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Ishii
authors.affiliation: Department of Surgery, Nishikobe Medical Center, Kobe, Hyogo.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kyogoku
authors.affiliation: Department of Colorectal Surgery, Kansai Rosai Hospital, Amagasaki, Hyogo.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kato
authors.affiliation: Kagawa University Hospital Cancer Center, Kita-gun, Kagawa.
authors.forename: Akihito
authors.initials: A
authors.lastname: Tsuji
authors.affiliation: Department of Human Health and Medical Sciences, Kochi Medical School, Kochi University, Nangoku, Kochi, Japan.
authors.forename: Michiya
authors.initials: M
authors.lastname: Kobayashi
keywords: XELOX plus bevacizumab; metastatic colorectal cancer; observational cohort study; treatment continuity