title: Cancer risk in patients with rheumatoid arthritis treated with anti-tumor necrosis factor alpha therapies: does the risk change with the time since start of treatment?
abstract: OBJECTIVE
  To determine the short-term and medium-term risks of cancer in patients receiving anti-tumor necrosis factor alpha (anti-TNFalpha) therapies that have proven effective in the treatment of chronic inflammatory conditions.
  
  
  METHODS
  By linking together data from the Swedish Biologics Register, Swedish registers of RA, and the Swedish Cancer Register, we identified and analyzed for cancer occurrence a national cohort of 6,366 patients with RA who first started anti-TNF therapy between January 1999 and July 2006. As comparators, we used a national biologics-naive RA cohort (n = 61,160), a cohort of RA patients newly starting methotrexate (n = 5,989), a cohort of RA patients newly starting disease-modifying antirheumatic drug combination therapy (n = 1,838), and the general population of Sweden. Relative risks (RRs) were estimated using Cox regression analyses, examining overall RR as well as RR by time since the first start of anti-TNF therapy, by the duration of active anti-TNF therapy, and by the anti-TNF agent received.
  
  
  RESULTS
  During 25,693 person-years of followup in 6,366 patients newly starting anti-TNF, 240 first cancers occurred, yielding an RR of 1.00 (95% confidence interval 0.86-1.15) versus the biologics-naive RA cohort, and similar RRs versus the other 2 RA comparators. RRs did not increase with increasing time since the start of anti-TNF therapy, nor with the cumulative duration of active anti-TNF therapy. During the first year following the first treatment start, but not thereafter, dissimilar cancer risks for adalimumab, etanercept, and infliximab were observed.
  
  
  CONCLUSIONS
  During the first 6 years after the start of anti-TNF therapy in routine care, no overall elevation of cancer risk and no increase with followup time were observed.
authors.affiliation: Department of Medicine Solna, Karolinska University Hospital at Solna and Karolinska Institutet, Stockholm, Sweden. johan.askling@ki.se
authors.forename: Johan
authors.initials: J
authors.lastname: Askling
authors.forename: Ronald F
authors.initials: RF
authors.lastname: van Vollenhoven
authors.forename: Fredrik
authors.initials: F
authors.lastname: Granath
authors.forename: Pauline
authors.initials: P
authors.lastname: Raaschou
authors.forename: C Michael
authors.initials: CM
authors.lastname: Fored
authors.forename: Eva
authors.initials: E
authors.lastname: Baecklund
authors.forename: Christina
authors.initials: C
authors.lastname: Dackhammar
authors.forename: Nils
authors.initials: N
authors.lastname: Feltelius
authors.forename: Lars
authors.initials: L
authors.lastname: Cöster
authors.forename: Pierre
authors.initials: P
authors.lastname: Geborek
authors.forename: Lennart T
authors.initials: LT
authors.lastname: Jacobsson
authors.forename: Staffan
authors.initials: S
authors.lastname: Lindblad
authors.forename: Solbritt
authors.initials: S
authors.lastname: Rantapää-Dahlqvist
authors.forename: Tore
authors.initials: T
authors.lastname: Saxne
authors.forename: Lars
authors.initials: L
authors.lastname: Klareskog
mesh_terms: D000068879:Adalimumab; D000368:Aged; D000911:Antibodies, Monoclonal / Q000009:adverse effects* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents / Q000009:adverse effects / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000453:epidemiology; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D000068800:Etanercept; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000009:adverse effects* / Q000627:therapeutic use; D015994:Incidence; D000069285:Infliximab; D008297:Male; D008727:Methotrexate / Q000009:adverse effects / Q000627:therapeutic use; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab; D000068879:Adalimumab; D000068800:Etanercept; D008727:Methotrexate