title: Survival Impact of Extracolorectal Malignancies in Colorectal Cancer Patients.
abstract: OBJECTIVE
  Colorectal cancer (CRC) patients are at high risk for developing extracolorectal malignancies (EMs). Although development of a second primary cancer and deaths thereof are included as events of disease-free survival (DFS) and overall survival (OS), the role of EMs in these survival end points has not been fully investigated.
  
  
  METHODS
  A total of 1,625 CRC patients who underwent surgery from April 2004 to March 2014 were retrospectively evaluated. EMs were classified as preoperative metachronous EMs (pre-MEMs), synchronous EMs (SEMs) and postoperative metachronous EMs (post-MEMs).
  
  
  RESULTS
  A total of 145 pre-MEMs (134 patients), 132 SEMs (125 patients) and 97 post-MEMs (89 patients) were observed. The incidence of SEM correlated with male sex, age >70 years and absence of distant metastasis. In patients undergoing curative surgery (n = 1,550), the 5-year CRC- and EM-related death, CRC-specific recurrence and post-MEM development rates were 10.4, 2.6, 27.9 and 7.3%, respectively. SEM strongly and independently correlated with shorter OS and DFS (hazard ratios, 2.52 and 1.54, respectively). Moreover, patients with SEM or those aged >70 years were at high risk for developing post-MEM.
  
  
  CONCLUSIONS
  Because the presence of SEM strongly indicates shorter DFS and OS, exploration of EMs prior to colorectal surgery is important.
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Kawai
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ishihara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nozawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hata
authors.forename: Tomomichi
authors.initials: T
authors.lastname: Kiyomatsu
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishikawa
authors.forename: Kensuke
authors.initials: K
authors.lastname: Otani
authors.forename: Koji
authors.initials: K
authors.lastname: Yasuda
authors.forename: Koji
authors.initials: K
authors.lastname: Murono
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Sasaki
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D016609:Neoplasms, Second Primary / Q000401:mortality*; D012189:Retrospective Studies; D012307:Risk Factors