title: Lower body mass index predicts worse cancer-specific prognosis in octogenarians with colorectal cancer.
abstract: BACKGROUND
  High body mass index (BMI) is a risk factor for colorectal cancer. However, the prognostic impact of BMI and other factors may differ between elderly and younger colorectal cancer patients. We analyze here prognostic factors in the surgical management of octogenarians with colorectal cancer and clarify the prognostic impact of BMI.
  
  
  METHODS
  Cox regression analysis and propensity score methods were used to retrospectively examine the association of BMI with mortality in 1613 octogenarian patients who underwent curative surgery for stage 0-III colorectal cancer.
  
  
  RESULTS
  In the Cox regression analysis, lower BMI (<18.5 kg/m(2); p = 0.001), age ≥83 years (p = 0.008), American Society of Anesthesiology class ≥3: (p = 0.001), performance status ≥2 (p = 0.003), Union for International Cancer Control (UICC) stage ≥III (p = 0.001), and postoperative adverse events (p = 0.001) were independently associated with decreased overall survival. Lower BMI (p = 0.001) and UICC stage ≥III (p = 0.001) were independently associated with decreased cancer-specific survival. After covariate adjustment, lower BMI was a risk factor for overall [hazard ratio (HR) 1.62; 95 % confidence interval (CI) 1.26-2.05; p = 0.0004] and cancer-specific survival (HR 2.00; 95 % CI 1.39-2.87; p = 0.0038) compared with normal BMI (18.5-24.9 kg/m(2)).
  
  
  CONCLUSIONS
  Lower BMI is significantly and independently associated with increased mortality risk in octogenarians who undergo curative surgery for colorectal cancer. Lower BMI should be used for prognosis assessment in octogenarians with colorectal cancer.
authors.affiliation: Department of Gastroenterological and Transplant Surgery Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan. adachitomohiro@hiroshima-u.ac.jp.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Adachi
authors.affiliation: Department of Gastroenterological and Transplant Surgery Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Hinoi
authors.affiliation: Department of Colon and Rectal Surgery, Shizuoka Cancer Center, Shizuoka, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kinugawa
authors.affiliation: Department of Surgery, Toho University, Ohashi Medical Center, Tokyo, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Enomoto
authors.affiliation: Department of Surgery, Niigata Cancer Center Hospital, Niigata, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Maruyama
authors.affiliation: Department of Surgery, Kinan Hospital, Wakayama, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Hirose
authors.affiliation: Department of Surgery, Kitasato University, School of Medicine, Sagamihara, Kanagawa, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Naito
authors.affiliation: Department of General and Gastroenterological Surgery, Osaka Medical College, Osaka, Japan.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Surgery, Nishinomiya Municipal Central Hospital, Nishinomiya, Hyougo, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Miyake
authors.affiliation: Department of Surgery, Kitasato University, School of Medicine, Japan Society of Laparoscopic Colorectal Surgery, Sagamihara, Kanagawa, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D000367:Age Factors; D000369:Aged, 80 and over; D015992:Body Mass Index; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008297:Male; D009367:Neoplasm Staging; D011379:Prognosis; D057216:Propensity Score; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Body mass index; Cancer-specific survival; Colorectal cancer; Octogenarian; Prognosis