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Ann Rheum Dis doi:10.1136/annrheumdis-2014-205745
  • Clinical and epidemiological research
  • Extended report

TNF inhibitor therapy and risk of breast cancer recurrence in patients with rheumatoid arthritis: a nationwide cohort study

  1. for the ARTIS Study Group
  1. 1Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet Stockholm, Sweden
  2. 2Clinical Pharmacology Unit Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
  3. 3Rheumatology Unit, Department of Medicine Solna, Karolinska Institutet Stockholm, Sweden
  1. Correspondence to Pauline Raaschou, Clinical Epidemiology Unit & Clinical Pharmacology Unit, Department of Medicine, Solna, Karolinska Institutet, T2:01, Stockholm SE-171 76, Sweden; Pauline.raaschou{at}karolinska.se
  • Received 14 April 2014
  • Revised 8 July 2014
  • Accepted 17 July 2014
  • Published Online First 8 August 2014

Abstract

Objective To investigate the risk of breast cancer recurrence in rheumatoid arthritis (RA)—patients with tumour necrosis factor inhibitor (TNFi) treatment and a history of breast cancer, taking several breast cancer, comorbidity and RA-related prognostic factors into account.

Methods 143 female TNFi-treated patients (1999–2010) with RA and a history of breast cancer before start of TNFi were identified through register linkages, and matched 1:1 from a cohort of 1598 comparable biologics-naive individuals. 120 TNFi-treated and 120 matched biologics-naive individuals with a history of equally recent/distant breast cancer met the eligibility criteria and comprised the final study population. The primary outcome was first recurrence of breast cancer. Through register-linkages and chart review, individuals were followed until 2011. HRs for recurrence were calculated using Cox regression.

Results The median time from breast cancer diagnosis until TNFi-treatment/start of follow-up was 9.4 years. Modest differences in breast cancer characteristics and/or treatment among TNFi-treated and biologics-naive individuals were noted at time of breast cancer diagnosis. Median follow-up from TNFi start was 4.9 years (4.6 years among biologics-naive). Among the TNFi-treated, 9 developed a breast cancer recurrence (crude incidence rate 15/1000 person-years) during follow-up, compared with 9 among the matched biologics-naive (16/1000 person-years). The adjusted corresponding HR was 1.1 (95% CI 0.4 to 2.8).

Conclusions Among patients with RA and a history of breast cancer, those who started TNFi-treatment did not experience more breast cancer recurrences than patients with RA treated otherwise. The generalisability of our findings to women with a very recent or a poor prognosis of breast cancer remains unknown.