Breast cancer tied to lower risk for 3 common autoimmune diseases

  • Chen HH & al.
  • PLoS ONE
  • 1 Jan 2019

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • Women with breast cancer appear to have lower risks for systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjögren's syndrome.
  • Risk for dermatomyositis /polymyositis was not affected.

Why this matters

  • First study of its kind suggests that impaired T-cell environment of breast cancer does not increase risk for major autoimmune diseases.

Study design

  • Population-based retrospective cohort (2007-2013) from the Taiwanese National Health Insurance Research Database.
  • Primary endpoint: incidence of major autoimmune diseases in women with breast cancer (n=54,311) vs noncancer control individuals (n=217,244) matched by age and the year of index date of major autoimmune diseases.
  • Funding: Taichung Veterans General Hospital, Taiwan.

Key results

  • Incidence rates per 100,000 women-years for women with vs without cancer:
    • SLE: 2.3 vs 10.0 (aHR, 0.04; 95% CI, 0.01-0.24).
    • RA: 19.3 vs 42.7 (aHR, 0.03; 95% CI, 0.02-0.04).
    • Sjögren's syndrome: 20.5 vs 38.2 (aHR, 0.21; 95% CI, 0.09-0.48).
  • No difference was observed between groups in incidence of dermatomyositis/polymyositis (2.3 vs 1.7 per 100,000 women-years; aHR, 0.37; 95% CI, 0.08-1.80).

Limitations

  • Retrospective, observational design.