title: Evaluation of the necessity of primary tumor resection for synchronous metastatic colorectal cancer.
abstract: OBJECTIVE
  We evaluated the need for primary tumor resection in patients with colorectal cancer (CRC) and synchronous unresectable metastases who underwent chemotherapy, and identified the associations between the primary tumor characteristics and risk of intestinal obstruction or perforation.
  
  
  METHODS
  We retrospectively analyzed the survival and complication rates of patients with synchronous metastatic CRC treated between April 2005 and December 2011.
  
  
  RESULTS
  Of 131 patients, 68 underwent primary tumor resection before chemotherapy, and 63 were treated without resection before chemotherapy. The overall survival (OS) did not significantly differ between the two groups (log-rank P = 0.53). In the resection group, 12 patients (17.6%) developed postoperative complications. In the non-resection group, 16 patients (25.4%) required surgical intervention owing to obstruction or perforation during their treatment. Surgical intervention did not affect the OS. A circumferential tumor was a risk factor for obstruction or perforation of the colorectum in non-resected patients (odds ratio = 11.163; P = 0.006).
  
  
  CONCLUSIONS
  Resection of primary tumors before chemotherapy is unnecessary in selected patients with synchronous metastatic colorectal cancer. A circumferential tumor is a risk factor for obstruction or perforation during chemotherapy in cases without primary tumor resection.
authors.affiliation: Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto, 860-8556, Japan, yuji-miyamoto@live.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Watanabe
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: Hironobu
authors.initials: H
authors.lastname: Shigaki
authors.forename: Asuka
authors.initials: A
authors.lastname: Murata
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Sugihara
authors.forename: Kojiro
authors.initials: K
authors.lastname: Etoh
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Ishimoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Iwatsuki
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Baba
authors.forename: Shiro
authors.initials: S
authors.lastname: Iwagami
authors.forename: Naoya
authors.initials: N
authors.lastname: Yoshida
authors.forename: Hideo
authors.initials: H
authors.lastname: Baba
mesh_terms: D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002166:Camptothecin / Q000008:administration & dosage / Q000031:analogs & derivatives; D015179:Colorectal Neoplasms / Q000150:complications / Q000188:drug therapy / Q000556:secondary* / Q000601:surgery*; D013505:Digestive System Surgical Procedures; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D007415:Intestinal Obstruction / Q000209:etiology; D007416:Intestinal Perforation / Q000209:etiology; D000077146:Irinotecan; D002955:Leucovorin / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D000077150:Oxaliplatin; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D000077146:Irinotecan; D002955:Leucovorin; D005472:Fluorouracil; D002166:Camptothecin