HR+ breast cancer: study nixes link between lower BMD and better survival

  • van Hellemond IEG & al.
  • Breast Cancer Res Treat
  • 2 Mar 2020

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

  • A prospective cohort study embedded within the DATA trial finds no relationship between reduced bone mineral density (BMD) and distant recurrence-free survival (DRFS) in postmenopausal patients with hormone receptor-positive (HR+) breast cancer.
  • The study also finds no relationship between bisphosphonate use and DRFS.

Why this matters

  • Study calls into question previous studies suggesting that use of bisphosphonates, and possibly lower BMD, improves breast cancer outcomes.

Study design

  • Prospective cohort preplanned substudy within the DATA phase 3 clinical trial comparing 6 vs 3 years of adjuvant anastrozole after 2-3 years of tamoxifen.
  • 1142 patients had dual-energy X-ray absorptiometry scans, which measures BMD, conducted before randomization to the 6- and 3-year groups.
  • Normal BMD T-score ≥−1.0; osteopenia T-score −2.5; osteoporosis T-score ≤−2.5.
  • Funding: AstraZeneca NL.

Key results

  • BMD was normal in 38.2%, osteopenia in 49.5%, and osteoporosis in 12.3%.
  • After a median follow-up of 5 years:
    • Compared with normal BMD, no relationship (adjusted HRs; 95% CIs) in the 6-year group between DRFS and:
      • Osteopenia: 0.82 (0.45-1.49).
      • Osteoporosis: aHR, 1.10 (0.26-4.67).
    • Compared with normal BMD, no relationship (adjusted HRs; 95% CIs) in the 3-year group between DRFS:
      • Osteopenia: 0.75 (0.40-1.42).
      • Osteoporosis: 1.86 (0.43-8.01).
    • No relationship between bisphosphonate use (vs no use) before randomization and DRFS.

Limitations

  • Observational design.