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SABCS Annual Symposium 2019: Preventing and treating hormone receptor-positive breast cancer

By BCRF | January 30, 2020

Researchers presented new findings on the management of ER-positive breast cancer.

The San Antonio Breast Cancer Symposium (SABCS) is the largest breast cancer meeting in the world. BCRF staff attends SABCS every year to hear updates on the latest breast cancer research, connect with BCRF researchers, and represent BCRF at advocacy events.

Highlights of the 2019 meeting, held on December 10th to the 14th, included updates on the treatment of ER-positive breast cancer and the prevention of recurrence:

Patients with high-risk estrogen receptor (ER)-positive breast cancers may be able to forgo chemotherapy prior to surgery.

ER-positive breast cancer, also referred to as luminal breast cancer, is the most commonly diagnosed form of the disease. When detected early, it typically has a very good 5-year prognosis. But not all luminal breast cancers have the same favorable prognosis. Luminal B breast cancer is typically more aggressive than luminal A breast cancer, and for this reason it is often treated with chemotherapy before surgery (neoadjuvant therapy).

The SOLTI-1402/CORALLEEN study (NCT03248427) is a Phase II study that aims to test whether neoadjuvant therapy with an anti-hormone drug (letrozole) plus a CDK4/6 inhibitor is just as effective in reducing the risk of recurrence as multi-drug chemotherapy in women with high-risk luminal B breast cancer. The investigators used the Prosigna® test (also known as PAM50) to determine a risk of relapse (ROR) score at the time of surgery.

Reporting at SABCS, the study investigators said they were encouraged to see similar clinical benefit (low ROR score) between the two therapeutic strategies and fewer side effects with the non-chemotherapy treatment. While these preliminary results need to be confirmed in additional studies and patient follow-up, the study also demonstrated the utility of molecular diagnostics in guiding treatment and assessing treatment response. This study was supported in part by BCRF and was published in The Lancet Oncology.

Breast cancer prevention benefits of aromatase inhibitor therapy continue long after stopping treatment.

Anti-hormone therapy with tamoxifen or an aromatase inhibitor (AI) is an effective prevention strategy in women at high risk of breast cancer or a breast cancer recurrence. The International Breast Cancer Intervention Study (IBIS-II) was designed to determine whether 5 years of the AI anastrozole can safely and effectively prevent breast cancer in postmenopausal women with a high risk of the disease as determined by family or personal history or presence of breast density. In the study, 3,864 high-risk women were randomized to receive anastrozole or placebo for 5 years.

The results, presented at SABCS by BCRF investigator, Jack Cuzick, PhD, FRS, CBE, reported on the incidence of breast cancer after a median of 10.9 years of follow-up, starting after treatment ended. The latest results confirmed earlier reports at 7 years of follow-up that 5 years of anastrozole reduced the risk of estrogen receptor-positive breast cancer by 54 percent. These results further support the use of anastrozole for prevention of ER-positive breast cancer in high-risk postmenopausal women.

To read more of our coverage from SABCS 2019, click the links below:

BCRF Researchers Honored at the 2019 San Antonio Breast Cancer Symposium

Highlights from SABCS Annual Symposium 2019: HER2-Positive Breast Cancer Updates

Highlights from SABCS Annual Symposium 2019: Examining the future of immunotherapy for breast cancer

Highlights from SABCS Annual Symposium 2019: Determining the Risk of Recurrence in Early-Stage Breast Cancer