Back December 19, 2016

Highlights from the San Antonio Breast Cancer Symposium (SABCS)

Last week marked another busy and exciting few days at the 2016 San Antonio Breast Cancer Symposium (SABCS), a five-day conference geared toward an international community of more than 7,000 physicians, researchers, and advocates. The purpose of the annual meeting is to share and discuss data and insights from groundbreaking research on breast cancer biology, prevention, and therapy. The meeting and related events and activities provide a collaborative forum to learn and communicate about breast cancer research and advancements from all around the world.

One of the hottest topics of the conference for ER+ breast cancer was the topic of extended anti-estrogen therapy. For those interested in hearing more, we’ve selected some highlights below.

Sessions We Can’t Stop Talking About

Data Presented on Extended Aromatase Inhibitor Therapy1

One of the key points of discussion for ER+ breast cancer at this year’s SABCS was the topic of extended treatment with an aromatase inhibitor, or AI, which works by stopping the production of estrogen in postmenopausal women. Results were presented from three extended anti-estrogen therapy trials – NSABP B-42, DATA and IDEAL – that assessed extended AI therapy beyond 5 years.  In the NSABP B-42 trial, the largest of the three, nearly 4,000 post-menopausal patients who completed 5 years of anti-estrogen therapy with either five years of an AI or three years of tamoxifen followed by an AI (for a total of 5 years) were randomized to receive either another 5 years of an AI or 5 years of a placebo.

Here are the highlights from the studies:

  • None of the three studies presented achieved their primary goal, to demonstrate a significant benefit in the entire study cohort. However, the results of two of the studies (B-42 and DATA) were generally consistent with previous extended anti-estrogen therapy trials showing that extended anti-estrogen therapy reduced the proportion of ER+ breast cancer patients that had a recurrence by ~3-4%
  • In the B-42 study there was a statistically significant benefit in terms of prevention of metastatic (distant) recurrences (3.9% with letrozole compared to 5.8% with placebo).

So what does this mean? In light of the trial results, treatment with an AI therapy for more than 5 years will likely not be recommended by most physicians for all patients. Rather, many physicians will look to try to identify which patients are most likely to benefit from extended treatment.

Dr. Eleftherios Mamounas of the University of Florida, and principal investigator of the B-42 trial, said, “. . .genomic classifiers that predict risk of late recurrence and benefit from extended anti-estrogen therapy may help to further individualize the recommendation for extended aromatase inhibitor therapy.”

During a post-plenary session, Dr. Michael Gnant of the Medical University of Vienna further highlighted the Breast Cancer Index (BCI) as the only available test with predictive data for likelihood of benefit from extended endocrine therapy.

BCI is a unique genomic test to help understand an individual woman’s likelihood of benefit from extended anti-estrogen therapy. To learn more about the genomic tests that can help with the extended anti-estrogen treatment decision, visit

Learn more about the data presented at SABCS. Learn More

Comparison of Biomarkers for Assessment of Risk of Recurrence in ER+ Early-Stage Breast Cancer2

An analysis comparing six different biomarkers (CTS [an algorithm using clinical variables], IHC4, OncotypeDx, Breast Cancer Index, Prosigna, and EndoPredict) and their ability to assess risk of recurrence in ER+ breast cancer was presented Friday afternoon during SABCS.  The biomarkers were evaluated for performance in assessing risk of recurrence in years 0-10 and 5-10 following initial diagnosis for both lymph node-negative (LN-) and lymph node-positive (LN+) patient groups.

For LN- patients:

All six biomarkers were able to assess risk of metastatic recurrence over years 0-10 following initial diagnosis, while only Breast Cancer Index, Prosigna, and EndoPredict* were able to significantly predict risk of metastatic recurrence between years 5-10.

For LN+ patients:

The study showed that predicting risk of recurrence is greatly improved when genomic tests are combined with clinical factors. Both Prosigna and EndoPredict were evaluated in this way and demonstrated the ability to assess risk of recurrence between years 0-10 and 5-10.  Notably, although it was not evaluated in this analysis, the Breast Cancer Index prognostic test for LN+ patients (1-3 nodes) also combines its genomic information with clinical factors to assess risk of late distant recurrence for LN+ (1-3 positive nodes) patients.

Understanding your personal risk of recurrence at different time points (0-10 years and 5-10 years) will help you and your doctor with two important treatment decisions:

  1. The evaluation of the tests’ ability to evaluate risk of metastatic recurrence from the time of diagnosis to year 10 helps determine which tests may be appropriate to help make initial treatment decisions regarding adjuvant chemotherapy.
  2. The evaluation of the tests’ ability to assess risk of late metastatic recurrence (between years 5-10) identifies which tests may help with the decision to 1wcontinue or stop anti-estrogen therapy after an initial 5 years of treatment.

It is important to understand that while this comparative analysis evaluates each test’s ability to assess risk of recurrence, when determining the best treatment plan for you, it is also important to understand whether or not you are likely to benefit from therapy.  Discuss the tests with your doctor to find out which one can provide the information you need to help with your treatment decisions.

Panel Discussion on Extended Anti-Estrogen Therapy

In a Biotheranostics-supported panel presentation entitled, “Extended Adjuvant Endocrine Therapy: A Panel Discussion on Balancing Risk vs. Benefit and Identifying the Right Women for Prolonged Therapy,” some of the top oncologists in breast cancer led a conversation about continued anti-estrogen treatment after an initial 5 years of therapy. Dr. Eleftherios Mamounas began the presentation by summarizing clinical trial data on extending anti-estrogen therapy. He again emphasized that use of more than 5 years of AI therapy may not be recommended to all patients, and genomic tests may help select individual patients who are likely to benefit.  Dr. Hope Rugo from the University of California San Francisco went into further depth about genomic testing, noting that while there are several tests that evaluate risk of recurrence after 5 years, only one test, the Breast Cancer Index, also has data demonstrating the ability to predict likelihood of benefiting from extended anti-estrogen treatment. Dr. William Gradishar from Northwestern University, closed out the presentation by providing a glimpse into the future for these genomic tests and the growing body of data that is likely to help further substantiate them.

Test for early-stage, ER+ Breast Cancer Therapy Evaluated for Impact on Physician Decision-Making3

A breast cancer test validated to assess risk of late recurrence and predict a patient’s likelihood to benefit from extended anti-estrogen therapy was tested in a prospective study designed to evaluate its impact on physician decision-making. The study looked at 141 patients with early-stage, hormone-receptor positive breast cancer who had completed at least 3.5 years of anti-estrogen therapy. Both patients and their healthcare providers completed pre- and post-test questionnaires, and patients also completed surveys related to anxiety levels and decision-making conflict.

Results showed that application of the tool in clinical practice had a significant impact on physician recommendations for extended anti-estrogen therapy, with recommendations changing in ~30% of cases. Furthermore, the study showed a significant increase in physicians’ confidence in decision-making, and a significant increase in overall patient satisfaction.

Partner Collaboration & Networking

SABCS provided many opportunities to connect with peers in breast cancer research, and welcomed patient advocates representing various advocacy, education and survivor support organizations. The San Antonio Breast Cancer Foundation hosted a number of mentoring sessions for these advocates throughout the week.

If you attended the conference as a patient advocate, we’d love to hear about your experience. Email us at

Be sure to check back for breast cancer tips and news. Remember to sign up for our newsletter to get the latest delivered right to your inbox – or talk to us on Twitter & Facebook!

This material was not created by Biotheranostics, Inc. The content, products and services discussed in this material are offered to educate healthcare providers and/or consumers on molecular diagnostic testing performed by Biotheranostics, and should not be considered or used as a substitute for medical advice, diagnosis or treatment for specific medical conditions.

The content, products and services discussed are offered to educate consumers on health care and medical issues that may affect their daily lives and should not be considered, or used as a substitute for, medical advice, diagnosis or treatment. You should always talk to your healthcare provider for diagnosis and treatment information, including your specific medical needs, and to answer any questions regarding personal health or medical conditions.
*Prosigna, and EndoPredict are trademarks of the respective owners of these products. EndoPredict is not commercially available in the US at this time.


  1. Mamounas EP et al. NSABP B-42. S1-05. SABCS 2016. Dec 7, 2016.
  2. Sestak I. Comprehensive comparison of prognostic signatures for breast cancer in TransATAC. S6-05. SABCS 2016. Dec 9, 2016.
  3. Sanft T, Hatzis C, Puztai. A multi-institutional, prospective study of incorporating the genomic platform Breast Cancer Index as a tool for decision-making regarding extension of adjuvant endocrine therapy. P2-09. SABCS 2016. Dec 8, 2016.