title: The importance of blood-borne viruses in elevated cancer risk among opioid-dependent people: a population-based cohort study.
abstract: OBJECTIVE
  To quantify cancer risk in opioid dependence and the association with infection by the oncogenic blood-borne viruses (BBVs) hepatitis C (HCV), hepatitis B (HBV) and HIV.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  New South Wales, Australia.
  
  
  METHODS
  All 45 412 adults aged 16 years or over registered for opioid substitution therapy (OST) between 1985 and 2007. Notifications of cancer, death and infection with HCV, HBV and HIV were ascertained by record linkage with registries.
  
  
  METHODS
  The ratios of observed to expected number of cancers, standardised incidence ratios (SIRs), and the average annual per cent change (AAPC) in overall age and sex-standardised cancer incidence.
  
  
  RESULTS
  Overall cancer risk was modestly increased compared to the general population (SIR 1.15, 95% CI 1.07 to 1.23). Excess risk was observed for 11 cancers, particularly lung (4.02, 95% CI 3.32 to 4.82), non-Hodgkin's lymphoma (1.51, 95% CI 1.20 to 1.88) and liver (8.04, 95% CI 6.18 to 10.3). Reduced risk was observed for six cancers, including prostate (0.16, 95% CI 0.06 to 0.32) and breast (0.48, 95% CI 0.35 to 0.62). Individuals notified with HCV or HBV had a markedly increased risk of liver cancer; lung cancer risk was also increased in those with HCV. HIV was associated with an elevated risk of liver, anus and kidney cancer, non-Hodgkin lymphoma and Kaposi sarcoma. Cancer risk was not increased in individuals without a BBV notification, apart from pancreatic cancer (3.92, 95% CI 1.07 to 10.0). Cancer incidence increased significantly over time (AAPC 9.4%, 4.2% to 15%, p=0.001).
  
  
  CONCLUSIONS
  BBVs play a major role in the cancer risk profile of opioid-dependent individuals registered for OST. To address the dramatic increasing trend in cancer incidence, the OST setting could be utilised for cancer prevention strategies.
authors.affiliation: Prince of Wales Clinical School, Adult Cancer Program, Lowy Cancer Research Centre, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Swart
authors.forename: Lucinda
authors.initials: L
authors.lastname: Burns
authors.forename: Limin
authors.initials: L
authors.lastname: Mao
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Grulich
authors.forename: Janaki
authors.initials: J
authors.lastname: Amin
authors.forename: Dianne L
authors.initials: DL
authors.lastname: O'Connell
authors.forename: Nicola S
authors.initials: NS
authors.lastname: Meagher
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Randall
authors.forename: Louisa
authors.initials: L
authors.lastname: Degenhardt
authors.forename: Claire M
authors.initials: CM
authors.lastname: Vajdic