Early breast cancer: no survival advantage from bilateral mastectomy

  • Kurian AW & al.
  • Cancer
  • 21 Nov 2019

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

  • Bilateral mastectomy (BLM) for early breast cancer (eBCa) is not associated with a survival advantage despite cutting the risk for second contralateral breast cancer (CBCa) by a small degree (around 34-43 cases per 10,000 person-years) relative to other surgical procedures.

Why this matters

  • BLM for eBCa is increasing in the United States.
  • This study suggests that BLM's lack of survival benefit should be weighed against its harms.

Study design

  • Retrospective cohort (n=245,418) of patients with eBCa stage 0-III from California (1998-2015) in the Surveillance, Epidemiology, and End Results database.
  • Absolute excess risk (AER) of CBC was assessed as the observed minus the expected number of BCas in the general population divided by 10,000 person-years at risk.
  • Funding: California Department of Public Health; CDC; NIH.

Key results

  • After a median follow-up of 6.7 years, 3.2% of the cohort developed CBCa.
  • AERs were greater after BCT (5.0 more cases per 10,000 person-years at risk) and after ULM (13.6 more cases per 10,000 person-years at risk) vs BLM (28.6 fewer cases per 10,000 years at risk).
  • BLM had no different risk for breast cancer death (HR, 1.03; 95% CI, 0.96-1.11) vs BCT.
  • ULM had higher risk for breast cancer death (HR, 1.21; 95% CI, 1.17-1.25) vs BCT.

Limitations

  • Retrospective observational design.