title: Increased cancer risks among arthroplasty patients: 30 year follow-up of the Swedish Knee Arthroplasty Register.
abstract: BACKGROUND
  An increasing number of young patients are undergoing knee arthroplasties. Thus, the long-term risks of having a knee prosthesis must be evaluated. This study focuses on the potential carcinogenic effects of the prosthesis; it is a long-term follow-up of all patients in Sweden between 1975 and 2006.
  
  
  METHODS
  The incidence of cancer in a total population of operated individuals was compared to the overall national cancer incidence in Sweden by means of standardised incidence ratios. Analysis of cancer latency period was performed to identify potential aetiological factors.
  
  
  RESULTS
  For male and female patients with rheumatoid arthritis (RA) or osteoarthritis (OA), the overall cancer risks were elevated, ranging from 1.10 (95% confidence interval (CI): 1.03-1.18) for men with OA to 1.26 (1.23-1.29) for men with RA. The greatest increases in risk were observed for the leukaemia subtypes, myelodysplastic syndromes (MDS) and essential thrombocytosis (ET), ranging from 3.31 (1.24-8.83) for ET in men with OA to 7.38 (1.85-29.51) for ET in women with RA. Increases in risk were also observed for breast cancer, prostate cancer and melanoma. The latency analysis revealed elevated risks late in the study period for both solid and haematopoietic cancers. However, only increases in MDS and possibly prostate cancer and melanoma rates appeared to be connected to the operation.
  
  
  CONCLUSIONS
  This study showed that OA and RA arthroplasty patients have a significantly higher risk of cancer than the general population. Elevated risks of MDS and possibly prostate cancer and melanoma indicated a potential connection to exposure to metals in the implant. The observed excessive incidence of ET was likely associated with the inflammatory disease.
authors.affiliation: Institute of Clinical Sciences Lund, Department of Orthopedics, Lund University Hospital, Lund University, Sweden. pw@nko.se
authors.forename: Philippe
authors.initials: P
authors.lastname: Wagner
authors.forename: Håkan
authors.initials: H
authors.lastname: Olsson
authors.forename: Lars
authors.initials: L
authors.lastname: Lidgren
authors.forename: Otto
authors.initials: O
authors.lastname: Robertsson
authors.forename: Jonas
authors.initials: J
authors.lastname: Ranstam
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000628:therapy; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007249:Inflammation; D007720:Knee Prosthesis / Q000009:adverse effects; D007938:Leukemia / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000150:complications / Q000209:etiology; D010003:Osteoarthritis / Q000150:complications / Q000628:therapy; D011471:Prostatic Neoplasms / Q000209:etiology / Q000628:therapy; D012042:Registries; D012306:Risk; D013548:Sweden; D013920:Thrombocythemia, Essential / Q000150:complications / Q000209:etiology