According to clinical trials, most patients on extended endocrine therapy are not likely to benefit.

Across 4 major trials, only about
3-5% of patients
benefited from extended endocrine therapy1-5

Better patient selection is needed to target patients who would most likely benefit from extended endocrine therapy.

Modest patient benefit:*

  • • MA.17 trial: 1 in 221,2
  • • ATLAS trial: 1 in 274
  • • ABCSG-6a trial: 1 in 233
  • • aTTom trial: 1 in 255
Menopausal Status Extended Treatment Trial Size Median Follow-up Risk of Recurrence
(Extended vs. Not Extended)
MA.17 Post Letrozole (Sy) vs PBO 5,187 2.5 y
Year 5-9
ABCSG 6a Post Anastrozole (3y) vs no treatment 856 5.2 y
Year 5-10
ATLAS Pre- and Post- Tamoxifen (5y) vs no treatment 6,846 10+ y
Year 5-15
aTTom Pre- and Post- Tamoxifen (5y) vs no treatment 6956 8.6 y
Year 0-15
Extended therapy
No Extended therapy

*Absolute benefits in extended endocrine therapy trials: MA.17 trial- 4.6% absolute benefit, based on 4-year disease-free survival: 94.4% with letrozole vs 89.8% with placebo; ABCSG-6a trial- 4.4% absolute benefit, based on 5-year recurrence rates: 7.8% with 3 years of anastrozole vs 12.2% with no extended treatment; ATLAS trial- 3.7% absolute benefit, based on 10-year recurrence rates: 21.4%
with extended tamoxifen vs 25.1% with no extended treatment; ATTom trial- 2.6% absolute benefit, based on 10-year recurrence rates: 28.0% with extended tamoxifen vs 32.0% with no extended treatment.

  1. Davies C, et al. Lancet Oncol. 2013;381:805-816.
  2. Jakesz R, et al. J Natl Cancer Inst. 2007;99:1845-1853.
  3. Goss PE, et al. J Natl Cancer Inst. 2005;97:1262-1271.
  4. Goss PE et al. N Engl J Med. 2003;349. 5.
  5. Sgroi DC, et al. J Natl Cancer Inst. 2013;105:1036-1042.
  6. Femara prescribing information, January 2014.
  7. Crew KD, et al. J Clin Oncol. 2007 Sep 1;25(25):3877-83.
  8. Arimidex prescribing information.
  9. Fallowfield LJ, et al. Breast Cancer Res Treat. 1999;55(2):189-99.
  10. Aromasin prescribing information.
  11. Nolvadex (tamoxifen citrate) product information. AstraZeneca Pharmaceuticals, 8-27-04.
  12. Conzen, SD. Managing the side effects of tamoxifen. In: UpToDate, Dizon DS (Ed), UpToDate, Waltham, MA. (Accessed on March 11, 2015.)
Breast Cancer Index Intended Use and Limitations

The Breast Cancer Index (BCI) Risk of Recurrence & Extended Endocrine Benefit Test is intended for use in patients diagnosed with estrogen receptor-positive (ER+), lymph node-negative (LN-) or lymph node positive (LN+; with 1-3 positive nodes) early-stage, invasive breast cancer, who are distant recurrence-free. BCI provides: 1) a quantitative assessment of the likelihood of both late (post-5 years) and overall (0-10 year) distant recurrence following an initial 5 years of endocrine therapy (LN- patients) or 5 years of endocrine therapy plus adjuvant chemotherapy (LN+ patients), and 2) prediction of likelihood of benefit from extended (>5 year) endocrine therapy. BCI results are adjunctive to the ordering physician’s workup; treatment decisions require correlation with all other clinical findings.

This test was developed and its performance characteristics determined by Biotheranostics, Inc. lt has not been cleared or approved by the U.S. Food and Drug Administration. This test is used for clinical purposes. lt should not be regarded as investigational or for research. How this information is used to guide patient care is the responsibility of the physician. Biotheranostics is certified under the Clinical Laboratory lmprovement Amendments of 1988 to perform high complexity clinical laboratory testing.