title: Understanding the burden of human papillomavirus-associated anal cancers in the US.
abstract: BACKGROUND
  Anal cancer is an uncommon malignancy in the US; up to 93% of anal cancers are associated with human papillomavirus.
  
  
  METHODS
  Cases diagnosed between 1998 and 2003 from 39 population-based cancer registries were analyzed. The following anal cancer histologies were included in the analysis: squamous cell, adenocarcinoma, and small cell/neuroendocrine carcinomas. Incidence rates were age-adjusted to the 2000 US standard population.
  
  
  RESULTS
  From 1998 through 2003, the annual age-adjusted invasive anal cancer incidence rate was 1.5 per 100,000 persons. Squamous cell carcinoma (SCC) was the most common histology overall, accounting for 18,105 of 21,395 (84.6%) cases of anal cancer. Women had a higher rate of SCC (1.5 per 100,000) than men (1.0). Whites and blacks had the highest incidence rate (1.3), whereas Asians/Pacific Islanders (API) had the lowest rate (0.3). Incidence rates of anal SCC increased 2.6% per year on average. The majority of SCC cases were diagnosed at the in situ or localized stage (58.1%). API were more likely to be diagnosed with regional or distant stage disease than were other racial/ethnic groups (27.5% and 11.8%, respectively). Males had lower 5-year relative survival than females for all stages of disease.
  
  
  CONCLUSIONS
  Rates of anal SCC varied by sex, race, and ethnicity. A higher proportion of API were diagnosed at regional/distant stage. Men had lower 5-year survival rates than women. Continued surveillance and additional research are needed to assess the potential impact of the HPV vaccine on the anal cancer burden in the US.
authors.affiliation: Division of Cancer Prevention and Control, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Atlanta, Georgia 30341, USA. DAJoseph@cdc.gov
authors.forename: Djenaba A
authors.initials: DA
authors.lastname: Joseph
authors.forename: Jacqueline W
authors.initials: JW
authors.lastname: Miller
authors.forename: Xiaocheng
authors.initials: X
authors.lastname: Wu
authors.forename: Vivien W
authors.initials: VW
authors.lastname: Chen
authors.forename: Cyllene R
authors.initials: CR
authors.lastname: Morris
authors.forename: Marc T
authors.initials: MT
authors.lastname: Goodman
authors.forename: Jose M
authors.initials: JM
authors.lastname: Villalon-Gomez
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Williams
authors.forename: Rosemary D
authors.initials: RD
authors.lastname: Cress
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001005:Anus Neoplasms / Q000453:epidemiology* / Q000208:ethnology / Q000473:pathology / Q000821:virology*; D044383:Black People; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology* / Q000208:ethnology; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D044468:Native Hawaiian or Pacific Islander; D030361:Papillomavirus Infections / Q000150:complications* / Q000453:epidemiology* / Q000208:ethnology; D012042:Registries; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D001741:Black or African American