title: Clinical pattern and progression of ulcerative proctitis in the Japanese population: a retrospective study of incidence and risk factors influencing progression.
abstract: OBJECTIVE
  The rate of extension of proctitis in Western countries has been reported, but no data regarding long-term follow-up have been described for the Japanese population. Additionally, patients with long-standing or extensive ulcerative colitis have an increased risk for developing colorectal cancer. This study evaluated both the rate of extension of the disease and the development of neoplasia among patients with an initial diagnosis of ulcerative proctitis.
  
  
  METHODS
  We retrospectively investigated the medical charts of patients with proctitis from 1979 to 2014. The primary focus of this research was the extension of the inflammatory area. The secondary focus included risk factors for disease extension and the development of neoplasia.
  
  
  RESULTS
  Sixty-six patients satisfied the inclusion criteria. Proximal extension of the disease occurred in 34 patients: 19 patients had left-sided colitis and 15 had pancolitis. According to a multivariate analysis, disease extension was significantly higher in patients with disease onset before 25 years of age (P-value = 0.043). The cumulative rates of disease extension at 10 and 20 years were 33.8% and 52.2%, respectively. Three patients were diagnosed with dysplasia during follow-up, all of whom experienced disease extension before the development of dysplasia.
  
  
  CONCLUSIONS
  The rate of extension of ulcerative colitis in the Japanese population was comparable to that in Western countries. A younger age of disease onset was associated with disease extension. Extension of proctitis may be associated with an increased risk of colorectal cancer.
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Anzai
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hata
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kishikawa
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ishii
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nishikawa
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Tanaka
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kiyomatsu
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kawai
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nozawa
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kazama
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Sunami
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kitayama
authors.affiliation: Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011350:Proctocolitis / Q000150:complications / Q000453:epidemiology / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Dysplasia; progression of ulcerative colitis; younger age at symptom onset