title: Long-term risk of receiving a total hip replacement in cancer patients.
abstract: OBJECTIVE
  To investigate whether cancer patients have an increased risk of receiving a total hip replacement compared to the standard population of Norway.
  
  
  METHODS
  By linking of The Cancer Register of Norway and The Norwegian Arthroplasty Register we obtained information on cancer diagnoses (type, date of diagnosis), total hip arthroplasties and date of death for all patients living in Norway. This includes 741,901 patients categorized into three groups: 652,197 patients with at least one cancer diagnosis but no hip arthroplasties, 72,469 patients with at least one hip arthroplasty but no cancer diagnosis and 17,235 patients who have at least one cancer diagnosis and at least one hip arthroplasty. Within this latter group, 8563 individuals had been diagnosed with cancer prior to a total hip arthroplasty. Statistical methods applied in this study were Cox interval censored regression models and standardized incidence ratios (SIR).
  
  
  RESULTS
  Cancer patients had a slightly increased risk of receiving a total hip arthroplasty compared to the Norwegian population (SIR=1.15 (95% CI, 1.12-1.17)). For primary tumours located cranially to the pelvic area there was no significant increase in risk for hip arthroplasty. An exception was breast cancer (SIR=1.13 (95% CI 1.08-1.18)). Cancer located in the pelvic region (SIR=1.20 (95% CI 1.16-1.24)), malignant lymphoma (SIR=1.30 (95% CI 1.15-1.46)) and leukaemia (SIR=1.17 (95% CI 1.01-1.34)) had an increased risk for receiving a total hip arthroplasty.
  
  
  CONCLUSIONS
  Cancer survivors, mainly those with pelvic and lympho-hematological malignancies, have a small statistically significant increase in risk for receiving total hip arthroplasty.
authors.affiliation: The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, N-5021 Bergen, Norway. Eva.Dybvik@helse-bergen.no
authors.forename: Eva
authors.initials: E
authors.lastname: Dybvik
authors.forename: Ove
authors.initials: O
authors.lastname: Furnes
authors.forename: Sophie D
authors.initials: SD
authors.lastname: Fosså
authors.forename: Clement
authors.initials: C
authors.lastname: Trovik
authors.forename: Stein Atle
authors.initials: SA
authors.lastname: Lie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007938:Leukemia / Q000150:complications* / Q000453:epidemiology; D008223:Lymphoma / Q000150:complications / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications* / Q000453:epidemiology; D009664:Norway / Q000453:epidemiology; D010386:Pelvic Neoplasms / Q000150:complications / Q000453:epidemiology; D016016:Proportional Hazards Models; D012042:Registries; D012044:Regression Analysis; D012306:Risk; D055815:Young Adult