title: Anal canal malignancies: a review in an Asian population.
abstract: BACKGROUND
  Anal canal malignancies are rare tumours of the gastrointestinal tract that represent less than five percent of anorectal malignancies.
  
  
  METHODS
  We retrospectively reviewed patients with anal canal malignancies who were treated from April 1989 to December 2008. Patients were identified from a prospective database and records were analysed for age, gender, presenting symptoms, duration of symptoms, mode of diagnosis, histological subtypes, stage of disease, treatment received, duration of follow-up, recurrence rates and survival.
  
  
  RESULTS
  A total of 61 patients were treated for anal canal malignancies, comprising 2.1 percent of all anorectal malignancies treated during the same period. There were 31 male and 30 female patients, with a median age at diagnosis of 61 (range 38-83) years. The commonest presenting symptoms were per rectal bleeding (69.4 percent) and pain (33.9 percent). The commonest histology was adenocarcinoma (50.8 percent) and squamous cell carcinoma (SCC) (40.3 percent). Patients underwent either surgery, radiotherapy, chemoradiation or a combination of modalities. The median duration of follow-up was 28 (range 1-120) months. Five patients developed recurrences after a median of 23 (range 2-36) months. The five-year overall survival and disease-free survival was 65.5 percent and 63.7 percent, respectively, with SCC showing a trend toward a better prognosis.
  
  
  CONCLUSIONS
  Anal canal tumours are a rare clinical entity. They are usually present in the elderly with per rectal bleeding. They are usually treated using a multimodality approach, after the accurate establishment of histological diagnosis, which can yield reasonable survival rates.
authors.affiliation: Department of Colorectal Surgery, Singapore General Hospital, Outram Road, Singapore 169608.
authors.forename: M T C
authors.initials: MT
authors.lastname: Wong
authors.forename: J F
authors.initials: JF
authors.lastname: Lim
authors.forename: K W
authors.initials: KW
authors.lastname: Eu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001003:Anal Canal / Q000473:pathology*; D001005:Anus Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000208:ethnology*; D018572:Disease-Free Survival; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000208:ethnology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D012846:Singapore; D016896:Treatment Outcome