title: Overcoming the challenges of primary tumor management in patients with metastatic colorectal cancer unresectable for cure and an asymptomatic primary tumor.
abstract: BACKGROUND
  The management of asymptomatic primary tumor in patients with unresectable metastatic colorectal cancer remains inconsistent.
  
  
  OBJECTIVE
  This study aimed to determine the rate of symptom-directed surgery after systemic chemotherapy and to estimate the impact of initial primary tumor resection on survival in patients with unresectable metastatic colorectal cancer and an asymptomatic primary tumor.
  
  
  METHODS
  This was a single-institution, retrospective observational study.
  
  
  METHODS
  The study was conducted in a tertiary referral hospital.
  
  
  METHODS
  Between 2005 and 2011, 191 consecutive patients with newly diagnosed stage IV colorectal cancer were identified. Of the 191, we analyzed 94 patients with unresectable, asymptomatic colorectal cancer.
  
  
  METHODS
  We measured symptom-directed surgery and overall survival.
  
  
  RESULTS
  Forty-seven patients with an intact primary tumor received systemic chemotherapy (upfront chemotherapy group), 41 underwent primary tumor resection (upfront primary tumor resection group), and 6 underwent diversion enterostomy as first-line therapy. After excluding the 6 patients undergoing diversion enterostomy before systemic chemotherapy, this left 88 patients for final analysis. Twelve upfront chemotherapy patients required symptom-directed late surgery. Overall, 1-year and 2-year rates of symptom-directed surgery were 19.1% and 26.1%. In patients with nontraversable lesions by colonoscope at diagnosis, 64.3% required late intervention within 1 year. Competing risk regression analysis revealed that only colonoscopic traversability at diagnosis was significantly associated with symptom-directed late surgery (subhazard ratio, 7.9; p = 0.004). Median overall survival time was comparable between the 2 groups at 23.9 months for the upfront primary tumor resection group and 22.6 months for the upfront chemotherapy group (HR, 0.84; 95% CI: 0.51-1.39).
  
  
  CONCLUSIONS
  This study was limited by its retrospective nature and small sample size.
  
  
  CONCLUSIONS
  Approximately 75% of upfront chemotherapy patients with unresectable, asymptomatic stage IV colorectal cancer can be spared initial resection of the primary tumor. Colonoscopic findings of nontraversable lesions at diagnosis may predict the need for late surgical intervention.
authors.affiliation: 1Department of Surgery, Kyoto University Graduate School of Medicine, Kyoto, Japan 2Outpatient Oncology Unit, Kyoto University Hospital, Kyoto, Japan 3Department of Experimental Therapeutics, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Suguru
authors.initials: S
authors.lastname: Hasegawa
authors.forename: Shigemi
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Horimatsu
authors.forename: Kae
authors.initials: K
authors.lastname: Okoshi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamada
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawada
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Sakai
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000556:secondary / Q000601:surgery*; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D058070:Asymptomatic Diseases / Q000628:therapy; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery*; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D053208:Kaplan-Meier Estimate; D002955:Leucovorin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009944:Organoplatinum Compounds / Q000627:therapeutic use; D016016:Proportional Hazards Models; D012189:Retrospective Studies
chemical_list: D009944:Organoplatinum Compounds; D002955:Leucovorin; D005472:Fluorouracil