title: Prognostic value of resection of primary tumor in patients with stage IV colorectal cancer: retrospective analysis of two randomized studies and a review of the literature.
abstract: BACKGROUND
  In patients with metastatic colorectal cancer (mCRC) with an asymptomatic primary tumor, there is no consensus on the indication for resection of the primary tumor.
  
  
  METHODS
  A retrospective analysis was performed on the outcome of stage IV colorectal cancer (CRC) patients with or without resection of the primary tumor treated in the phase III CAIRO and CAIRO2 studies. A review of the literature was performed.
  
  
  RESULTS
  In the CAIRO and CAIRO2 studies, 258 and 289 patients had undergone a primary tumor resection and 141 and 159 patients had not, respectively. In the CAIRO study, a significantly better median overall survival and progression-free survival was observed for the resection compared to the nonresection group, with 16.7 vs. 11.4 months [P<0.0001, hazard ratio (HR) 0.61], and 6.7 vs. 5.9 months (P=0.004; HR 0.74), respectively. In the CAIRO2 study, median overall survival and progression-free survival were also significantly better for the resection compared to the nonresection group, with 20.7 vs. 13.4 months (P<0.0001; HR 0.65) and 10.5 vs. 7.8 months (P=0.014; HR 0.78), respectively. These differences remained significant in multivariate analyses. Our review identified 22 nonrandomized studies, most of which showed improved survival for mCRC patients who underwent resection of the primary tumor.
  
  
  CONCLUSIONS
  Our results as well as data from literature indicate that resection of the primary tumor is a prognostic factor for survival in stage IV CRC patients. The potential bias of these results warrants prospective studies on the value of resection of primary tumor in this setting; such studies are currently being planned.
authors.affiliation: Department of Medical Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Sabine
authors.initials: S
authors.lastname: Venderbosch
authors.forename: Johannes H
authors.initials: JH
authors.lastname: de Wilt
authors.forename: Steven
authors.initials: S
authors.lastname: Teerenstra
authors.forename: Olaf J
authors.initials: OJ
authors.lastname: Loosveld
authors.forename: Aart
authors.initials: A
authors.lastname: van Bochove
authors.forename: Harm A
authors.initials: HA
authors.lastname: Sinnige
authors.forename: Geert-Jan M
authors.initials: GJ
authors.lastname: Creemers
authors.forename: Margot E
authors.initials: ME
authors.lastname: Tesselaar
authors.forename: Linda
authors.initials: L
authors.lastname: Mol
authors.forename: Cornelis J A
authors.initials: CJ
authors.lastname: Punt
authors.forename: Miriam
authors.initials: M
authors.lastname: Koopman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017326:Clinical Trials, Phase III as Topic; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D012196:Review Literature as Topic; D015996:Survival Rate