Highlights From the San Antonio Breast Cancer Symposium 2020

This year’s San Antonio Breast Cancer Symposium was entirely virtual due to the COVID-19 pandemic.

The experience was very different this year without the in-person contact that all of us who attend are used to. I really missed having the opportunity to meet researchers and reconnect with fellow advocates and friends.

What wasn’t different though was the incredible amount of information being shared about advances in breast cancer research.

As I looked over my notes and thought about the takeaways I wanted to share, a theme seemed to emerge. It’s this: perhaps we’re finally beginning to see what’s referred to as “personalized medicine” become more of a reality in everyday breast cancer care. This is true for both early stage and advanced, or metastatic, breast cancer and for all sub-types, including triple negative breast cancer.

Personalized medicine is a fancy-sounding term, but what it means is that your treatment choices are based on the biology of your own cancer. So treatments you choose are more likely to help you. And you avoid wasting time–and dealing with the side effects–of treatments that are not likely to be beneficial.

With that theme in mind, here are my top three “take-home” highlights from the 2020 symposium.

Targeted Treatment for Triple Negative Metastatic Breast Cancer

Earlier this year, the FDA granted accelerated approval for a targeted treatment for triple negative metastatic breast cancer called sacituzumab govitecan (Trodelvy), an antibody-drug conjugate. I wrote about this development in a recent post on new treatments for triple negative breast cancer.

This was a very notable development because, until this approval, there had been fewer treatment options for TNBC compared to other types of breast cancer and they’ve been mostly limited to chemotherapy.

Researchers presented an analysis of certain findings from the ASCENT clinical trial, a Phase 3 trial which has confirmed significant overall survival benefits for metastatic TNBC patients receiving Trodelvy compared with standard chemotherapy.

In this analysis, the researchers focused on a biomarker called Trop-2 that is often expressed on TNBC cells (and in other cancers as well).

The results showed that patients whose cancers expressed medium to high levels of Trop-2 received the most benefit from Trodelvy, but that all patients benefited.

The side effects of this drug can potentially be serious, however, and patients receiving it need to be monitored carefully and any side effects addressed if they occur.

Do CDK 4/6 Inhibitors Help Those with Hormone Receptor-Positive Early Stage Breast Cancer with a Higher Risk of Recurrence?

A category of targeted therapies called CDK 4/6 inhibitors has been shown to be very effective in extending overall survival for patients with metastatic HR-positive breast cancer. Three of these drugs have been approved over the last few years.

A big outstanding question was whether CDK 4/6 inhibitors would help early stage HR-positive breast cancer patients who have a higher risk of recurrence to reduce that risk.

Results were presented from two clinical trials investigating that question.

The findings so far are mixed. Based on an interim analysis, the first trial, monarchE, found benefit for breast cancer patients receiving the drug abemaciclib (Verzenio) together with hormone therapy. The other trial, PENELOPE-B, however, did not show patients benefiting from palbociclib (Ibrance) together with hormone therapy.

Possible reasons given for the disparate findings, in additional to possible differences in the drugs themselves, included differences in the length of time that the treatments were given and differences in the length of follow up in these two trials.

Obtaining further results over time is going to be important. However, commenters were hopeful that, by finding biomarkers to identify the right subset of higher-risk patients in this group who can benefit most, these therapies can become a valuable option for some of these patients.

Personalized Therapy: Identifying More Individuals Who Do Not Need Chemotherapy

In the summer of 2018, the findings from the TAILORx clinical trial provided strong evidence that most women with HR-positive early stage breast cancer who have a midrange risk of recurrence will not benefit from chemotherapy and do not need it.

Risk of recurrence is measured by the Oncotype DX test, a 21-gene assay. This test scores recurrence risk on a scale of 1 to 100, with scores over 25 representing higher risk. I wrote about Oncotype DX and the TAILORx findings in this post.

After the TAILORx results came out, an important question remained to be answered. The women who participated in TAILORx all had stage I breast cancer with no lymph node involvement. Could women who have a small number of positive lymph nodes also safely avoid chemotherapy?

We heard results from the ongoing RxPONDER clinical trial, which is investigating whether patients with hormone receptor-positive breast cancer who have one to three positive lymph nodes–and a recurrence score of 25 or less–benefit from chemotherapy.

Results from RxPONDER were not expected for another two years. But the results so far were quite significant and the decision was made to report on those findings now.

The trial has revealed that post-menopausal women with HR-positive breast cancer who have one to three positive nodes and a recurrence score of 25 or less do not benefit from chemotherapy and do not need it.

The pre-menopausal women in the study as a group did benefit from chemotherapy. The trial organizers stressed there is more work to do to understand why these women are shown to benefit from chemotherapy, the role that ovarian suppression caused by chemotherapy may play, and whether some of these women can safely avoid chemo as well.

For More Information

If you’d like to read more about the research findings presented this year at San Antonio, here are some helpful resources:

• Living Beyond Breast Cancer – Highlights from the 2020 San Antonio Breast Cancer Symposium
• Breast Cancer Action – SABCS 2020
• Breastcancer.org – 2020 San Antonio Breast Cancer Symposium Coverage

Related Posts
Highlights from the San Antonio Breast Cancer Symposium 2019
New Treatments for Triple Negative Breast Cancer

Image Credit: Sean Pavone via Shutterstock