title: Trends in incidence and survival for anal cancer in New South Wales, Australia, 1972-2009.
abstract: BACKGROUND
  Little is known about the incidence and survival of anal cancer in New South Wales (NSW), Australia, as anal cancer cases are often grouped together with other colorectal cancers in descriptive epidemiological analyses.
  
  
  METHODS
  We studied patterns and trends in the incidence and survival of people diagnosed with anal cancer in NSW, Australia, 1972-2009 (n=2724). We also predicted anal cancer incidence in NSW during 2010-2032. Given the human papilloma virus-associated aetiology for most anal cancers, we quantified these changes over time in incidence and survival by histological subtype: anal squamous cell carcinoma (ASCC); and anal adenocarcinoma (AAC).
  
  
  RESULTS
  There was a linear increase in incident anal cancer cases in NSW with an average annual percentage change (AAPC) of 1.6 (95% CI 1.1-2.0) such that, in combination with age-period-cohort modelling, we predict there will be 198 cases of anal cancer in the 2032 calendar year (95% CI 169-236). Almost all of these anal cancer cases are projected to be ASCC (94%). Survival improved over time regardless of histological subtype. However, five-year relative survival was substantially higher for people with ASCC (70% (95% CI 66-74%)) compared to AAC (51% (95% CI 43-59%)), a 37% difference. Survival was also greater for women (69% (95% CI 64-73%)) with ASCC compared to men (55% (95% CI 50-60%)). It was not possible to estimate survival by stage at diagnosis particularly given that 8% of all cases were recorded as having distant stage and 22% had missing stage data.
  
  
  CONCLUSIONS
  Aetiological explanations, namely exposure to oncogenic types of human papillomavirus, along with demographic changes most likely explain the actual and projected increase in ASCC case numbers. Survival differences by gender and histological subtype point to areas where further research is warranted to improve treatment and outcomes for all anal cancer patients.
authors.affiliation: Cancer Epidemiology and Services Research (CESR), Sydney School of Public Health, Sydney Medical School, University of Sydney, NSW, Australia. Electronic address: jane.young@sydney.edu.au.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Soeberg
authors.affiliation: Cancer Epidemiology and Services Research (CESR), Sydney School of Public Health, Sydney Medical School, University of Sydney, NSW, Australia.
authors.forename: Kris
authors.initials: K
authors.lastname: Rogers
authors.affiliation: Cancer Institute NSW, Australia.
authors.forename: David C
authors.initials: DC
authors.lastname: Currow
authors.affiliation: Cancer Epidemiology and Services Research (CESR), Sydney School of Public Health, Sydney Medical School, University of Sydney, NSW, Australia; Surgical Outcomes Research Centre (SOuRCe), Sydney Local Health District and University of Sydney, NSW, Australia.
authors.forename: Jane M
authors.initials: JM
authors.lastname: Young
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology* / Q000821:virology; D000367:Age Factors; D000368:Aged; D001005:Anus Neoplasms / Q000453:epidemiology* / Q000821:virology; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology* / Q000821:virology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D027383:Papillomaviridae; D030361:Papillomavirus Infections / Q000150:complications / Q000453:epidemiology; D012737:Sex Factors
keywords: Adenocarcinoma; Anal cancer; Australia; Incidence; Relative survival; Squamous cell carcinoma