title: Risk of anal cancer in HIV-infected and HIV-uninfected individuals in North America.
abstract: BACKGROUND
  Anal cancer is one of the most common cancers affecting individuals infected with human immunodeficiency virus (HIV), although few have evaluated rates separately for men who have sex with men (MSM), other men, and women. There are also conflicting data regarding calendar trends.
  
  
  METHODS
  In a study involving 13 cohorts from North America with follow-up between 1996 and 2007, we compared anal cancer incidence rates among 34 189 HIV-infected (55% MSM, 19% other men, 26% women) and 114 260 HIV-uninfected individuals (90% men).
  
  
  RESULTS
  Among men, the unadjusted anal cancer incidence rates per 100 000 person-years were 131 for HIV-infected MSM, 46 for other HIV-infected men, and 2 for HIV-uninfected men, corresponding to demographically adjusted rate ratios (RRs) of 80.3 (95% confidence interval [CI], 42.7-151.1) for HIV-infected MSM and 26.7 (95% CI, 11.5-61.7) for other HIV-infected men compared with HIV-uninfected men. HIV-infected women had an anal cancer rate of 30/100 000 person-years, and no cases were observed for HIV-uninfected women. In a multivariable Poisson regression model, among HIV-infected individuals, the risk was higher for MSM compared with other men (RR, 3.3; 95% CI, 1.8-6.0), but no difference was observed comparing women with other men (RR, 1.0; 95% CI, 0.5-2.2). In comparison with the period 2000-2003, HIV-infected individuals had an adjusted RR of 0.5 (95% CI, .3-.9) in 1996-1999 and 0.9 (95% CI, .6-1.2) in 2004-2007.
  
  
  CONCLUSIONS
  Anal cancer rates were substantially higher for HIV-infected MSM, other men, and women compared with HIV-uninfected individuals, suggesting a need for universal prevention efforts. Rates increased after the early antiretroviral therapy era and then plateaued.
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, CA 94612, USA. michael.j.silverberg@kp.org
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Silverberg
authors.forename: Bryan
authors.initials: B
authors.lastname: Lau
authors.forename: Amy C
authors.initials: AC
authors.lastname: Justice
authors.forename: Eric
authors.initials: E
authors.lastname: Engels
authors.forename: M John
authors.initials: MJ
authors.lastname: Gill
authors.forename: James J
authors.initials: JJ
authors.lastname: Goedert
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Kirk
authors.forename: Gypsyamber
authors.initials: G
authors.lastname: D'Souza
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Bosch
authors.forename: John T
authors.initials: JT
authors.lastname: Brooks
authors.forename: Sonia
authors.initials: S
authors.lastname: Napravnik
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Hessol
authors.forename: Lisa P
authors.initials: LP
authors.lastname: Jacobson
authors.forename: Mari M
authors.initials: MM
authors.lastname: Kitahata
authors.forename: Marina B
authors.initials: MB
authors.lastname: Klein
authors.forename: Richard D
authors.initials: RD
authors.lastname: Moore
authors.forename: Benigno
authors.initials: B
authors.lastname: Rodriguez
authors.forename: Sean B
authors.initials: SB
authors.lastname: Rourke
authors.forename: Michael S
authors.initials: MS
authors.lastname: Saag
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Sterling
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Gebo
authors.forename: Natasha
authors.initials: N
authors.lastname: Press
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Martin
authors.forename: Robert
authors.initials: R
authors.lastname: Dubrow
mesh_terms: D000328:Adult; D001005:Anus Neoplasms / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009656:North America / Q000453:epidemiology; D018570:Risk Assessment; D012725:Sexual Behavior / Q000706:statistics & numerical data