title: Proximal shift of colorectal cancer along with aging.
abstract: BACKGROUND
  Although several reports have documented the increased incidence of right-sided colorectal cancer (CRC) in the elderly, especially in women, the gender-specific, age-related changes in the characteristics of CRCs, especially related to the cancer localization, have not been fully investigated. This study evaluated the age-related changes in the clinicopathologic features of CRCs, according to the gender.
  
  
  METHODS
  A total of 1059 consecutive patients with CRCs who were admitted to the authors' surgical department between February 2005 and June 2012 were retrospectively reviewed. The patients were divided into male (n = 632) and female (n = 427) groups and then according to the age group, and the correlation between the age group and the other clinicopathologic features was analyzed by univariate and multivariate analysis.
  
  
  RESULTS
  The number of concomitant adenomas found was significantly increased along with increasing age in men, and the presence of concomitant adenoma was the only independent age-related factor of male CRC in the multivariate analysis (P = .0044). In contrast, in women, the location of the CRC progressively shifted to the right side (proximal colon) with increasing age, and the presence of right-sided CRC was the only independent factor of female CRC in the multivariate analysis (P < .0001).
  
  
  CONCLUSIONS
  There was a significant gender-specific difference in the age-related changes in the characteristics of CRC. Increasing the number of concomitant adenomas and the shift of CRC localization to the proximal colon were the gender-specific characteristics of male and female CRC, respectively.
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. Electronic address: yiida-tky@umin.ac.jp.
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Iida
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Kawai
authors.affiliation: Department of Transfusion Medicine, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Nelson H
authors.initials: NH
authors.lastname: Tsuno
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Sunami
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Joji
authors.initials: J
authors.lastname: Kitayama
authors.affiliation: Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000556:secondary*; D000236:Adenoma / Q000473:pathology*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012307:Risk Factors
keywords: Adenoma; Elderly; Gender; Proximal colon