title: Endocarditis and risk of cancer: a Danish nationwide cohort study.
abstract: BACKGROUND
  Endocarditis may be a marker for bacteremia-associated occult cancer. Intensive antibiotic treatment in endocarditis is suggested to reduce long-term cancer risk. We examined these hypotheses in a nationwide cohort study.
  
  
  METHODS
  Endocarditis patients and cancer cases were identified from the Danish National Registry of Patients and the Danish Cancer Registry during 1978-2008. We compared the incidences of various cancers among study subjects to expected incidences based on national age-, sex-, and site-specific rates.
  
  
  RESULTS
  We observed 997 cancers among 8445 endocarditis patients (median follow-up of 3.5 years), reflecting an increased standardized incidence rate (SIR) of 1.61 (95% confidence interval [CI], 1.51-1.71). Cancer risk was highly elevated during the first 3 months of follow-up (SIR=8.03; 95% CI, 6.92-9.26), partly due to a 15- to 30-fold increased risk of hematological or liver cancers. Between 3-month and 5-year follow-ups, cancer incidence remained 1.5-fold higher than expected, including 2- and 4-fold increased SIRs for colorectal and liver cancers, respectively. Beyond 5 years of observation, the overall cancer SIR was 1.21 (95% CI, 1.10-1.34). Long-term associations were weak for several cancers hypothesized to be associated with antibiotic use, including prostate, gastric, and breast cancer.
  
  
  CONCLUSIONS
  Endocarditis is a substantial clinical marker for presence of occult cancer. We found no evidence of decreased long-term cancer risk after antibiotic treatment for endocarditis.
authors.affiliation: Department of Clinical Epidemiology, Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark. rwt@dce.au.dk
authors.forename: Reimar Wernich
authors.initials: RW
authors.lastname: Thomsen
authors.forename: Dóra Körmendiné
authors.initials: DK
authors.lastname: Farkas
authors.forename: Søren
authors.initials: S
authors.lastname: Friis
authors.forename: Claus
authors.initials: C
authors.lastname: Sværke
authors.forename: Anne Gulbech
authors.initials: AG
authors.lastname: Ording
authors.forename: Mette
authors.initials: M
authors.lastname: Nørgaard
authors.forename: Henrik Toft
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D004696:Endocarditis / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents