Breast cancer: study nixes link between aromatase inhibitors, fracture

  • Leslie WD & al.
  • Oncologist
  • 10 Jul 2019

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

  • Aromatase inhibitor (AI) therapy for breast cancer (BCa) is not associated with higher risk for fracture, according to a Canadian registry-based cohort study.

Why this matters

  • Although findings may be offset by higher baseline BMI, bone mineral density (BMD), and lower prevalence of prior fracture in AI-treated women, the study challenges conventional wisdom that all women starting AI therapy are at high risk for fracture.

Study design

  • Population-based, registry-based cohort (n=36,996) of women entered into a BMD registry for Manitoba, Canada.
  • Women aged ≥40 years were divided into 3 mutually exclusive groups:
    • BCa with ≥12 months of AI therapy (n=1775).
    • BCa with no AI therapy (n=1016).
    • General population (n=34,205).
  • Participants were linked to hospital discharge and physician billing claims.
  • Funding: None disclosed.

Key results

  • At baseline, the AI group had higher BMI, higher BMD, lower osteoporosis prevalence, and fewer fractures than the other 2 groups (all P<.001>
  • Median total exposure to AI, 4.2 years.
  • In adjusted analysis, the AI group had similar risks as the general population for:
    • Major osteoporotic fracture (hip, clinical spine, forearm, and humerus; HR, 1.15; 95% CI, 0.93-1.42).
    • Hip fracture (HR, 0.90; 95% CI, 0.56-1.43).
    • Any fracture (HR, 1.06; 95% CI, 0.88-1.28).

Limitations

  • Observational design.