Hormone Replacement Therapy May Increase Breast Cancer Risk in Young Women

Strategic Insights -

A new study published in the journal Lancet Oncology has found that using certain types of hormone replacement therapy (HRT) before menopause may increase the risk of breast cancer in young women. The researchers, from the National Institute of Environmental Health Sciences in the US, analyzed data from 459,476 women aged 16 to 54 years old and found that oestrogen plus progestin hormone therapy increased the risk of young breast cancer by 10%, while oestrogen hormone therapy decreased the risk by 14%. The study suggests that while HRT is not broadly linked to young-onset breast cancer, using certain types before menopause could increase the risk of it developing in young women.

Key Takeaways:

  • The study found that oestrogen hormone therapy appeared to reduce the risk of young breast cancer by 14%, while oestrogen plus progestin hormone therapy increased the risk by 10%.
  • The researchers analyzed data from 459,476 women aged 16 to 54 years old, of whom 2% (8,455) developed young-onset breast cancer.
  • Oestrogen plus progestin hormone therapy was found to increase the risk of breast cancer in certain women, particularly those who used it for more than two years or had not undergone surgery to remove their uterus or both ovaries.
  • The findings suggest that HRT is not broadly linked to young-onset breast cancer, but using certain types before menopause may increase the risk of it developing in young women.
  • The study's results are largely in line with what is already known about taking HRT for menopausal symptoms and its effects on breast cancer risk.

Statistics:

  • 459,476 women aged 16 to 54 years old were analyzed in the study.
  • 2% (8,455) of the women developed young-onset breast cancer.
  • 15% of the women involved in the study reported using hormone therapy, with oestrogen plus progestin hormone therapy and oestrogen being the most common types.
  • The study found that oestrogen hormone therapy reduced the risk of young breast cancer by 14%, while oestrogen plus progestin hormone therapy increased the risk by 10%.

Sources:

  • "Hormone therapy and breast cancer risk in premenopausal women: a systematic review and meta-analysis" (Lancet Oncology)
  • Breast Cancer Now (UK)
  • National Institute of Environmental Health Sciences (US)