Not All Women Benefit from an Extra 5 Years of Anti-Estrogen Therapy

After surgery, most early stage, estrogen receptor positive (ER+), breast cancer patients are ready for this difficult period of their lives to be over.

But unfortunately, breast cancer isn’t that simple.

To prevent ER+ breast cancer from returning, most women are prescribed anti-estrogen therapy for at least 5 years.

No one wants menopause-like symptoms, osteoporosis, fatigue, mood swings, and more…but evidence from randomized control trials demonstrates that for most women, anti-estrogen therapy is the best way to remain disease-free.

Treating early stage, (ER+) breast cancer with anti-estrogen therapy for 5 years has been shown to significantly reduce the chance of cancer returning, and recent research has found that 10 years of therapy can further improve disease-free survival.

But only 3 – 5% of women actually benefit from an additional 5 years.1-5

Coupled with the potentially severe side effects, it’s important for you and your doctor to know your personal likelihood of benefit.

So how can you and your doctor decide which approach is right for you?

Fortunately, there’s a simple, test that uses your original biopsy specimen.

Results from Breast Cancer Index (BCI) can help you and your doctor determine if extending anti-estrogen therapy is likely to decrease your individualized risk of recurrence.

To learn more about BCI, visit

Tell Me More


  1. Davies C, et al. Lancet. 2013;381:805-816.
  2. Gray RG, et al., J Clin Oncol. 2013;31(suppl):abstract 5.
  3. Goss PE, et al. J Natl Cancer Inst . 2005;97:1262-1271.
  4. Jakesz R, et al., J Natl Cancer Inst. 2007;99:1845-1853.
  5. 5. Goss PE et al. N Engl J Med. 2016 DOI: 10.1056 NEJMoa1604700).