Tripathy Offers Insights on Future of Breast Cancer From SABCS, ASCO

Katie Kosko
Published: Wednesday, Apr 19, 2017
Debu Tripathy, MD

Debu Tripathy, MD

The 34th Annual Miami Breast Cancer Conference® featured a recap of significant research from the 2016 ASCO Annual Meeting and the 2016 San Antonio Breast Cancer Symposium (SABCS). Debu Tripathy, MD, of The University of Texas MD Anderson Cancer Center, provided highlights of those meetings (Table). Tripathy served as co-chair of the conference, which Physicians’ Education Resource® (PER®) sponsored March 9 to 12 in Miami Beach, Florida.

Clinically Noteworthy Research From 2016: Top Abstracts From ASCO and SABCS

Table. Clinically Noteworthy Research From 2016: Top Abstracts From ASCO and SABCS

Extended Adjuvant Aromatase Inhibitor Therapy

Tripathy highlighted 4 trials that looked at extending aromatase inhibitor (AI) therapy beyond 5 years. The first was the phase III MA.17R trial, which compared letrozole with placebo. It found that women who extended their adjuvant therapy with an AI to 10 years after treatment for their early-stage hormone receptor (HR)–positive breast cancer reduced their risk of recurrence by more than a third and experienced no new toxicities or worsening of quality of life. However, the impact on distant metastases was minimal.1

Whereas the MA.17R trial showed promising disease-free survival (DFS) results, 3 other trials found that extended hormonal therapy with an AI did not improve DFS rates in patients with HR-positive breast cancer. The multicenter phase III DATA study compared 3 versus 6 years of anastrozole after 2 to 3 years of tamoxifen in postmenopausal women with HR-positive early breast cancer. The study found that the 5-year adapted DFS, the primary endpoint of the study, was 79% in the 3-year anastrozole treatment group and 83% in the 6-year treatment arm.2

The IDEAL study compared 7.5 and 10 years of hormonal therapy. Patients were randomized to letrozole for 2.5 or 5 years of extended therapy. The 5-year DFS rate was 88.4% in patients receiving an additional 2.5 years of treatment and 87.9% for those receiving 5 more years of treatment with letrozole (HR, 0.96; P = .70). Overall survival (OS) rates were 93.5% and 92.6%, respectively (HR, 1.08; P = .59).3

Then, in the NSABP B-42 trial, the DFS at approximately 7 years was 84.7% with extended letrozole versus 81.3% with placebo (HR, 0.85; P = .048, which did not achieve statistical significance based on the analysis plan). OS was 91.8% with letrozole compared with 92.3% for patients on placebo (HR, 1.15; P = .22).4

“We have typically used 5 years [of hormonal therapy], but many patients recur after 5 years, even 10, 20 years out,” said Tripathy. “Perhaps we should be selective about whom we give 10 years of aromatase inhibitor versus just 5 years, because you do have more side effects when you keep them on for longer. This should probably be con ned to patients who have high-risk breast cancer, such as stage III or high-risk stage II.” Adjuvant Anthracycline Therapy Does the use of adjuvant anthracycline therapy contribute to better outcomes despite the associated toxicity profile? The Anthracyclines in Early Breast Cancer (ABC) trials examined this question in women with high-risk, HER2-negative breast cancer. A pooled analysis of 3 studies found that anthracyclines do appear to be slightly better for patients. The phase III trials (USOR 06-090, NSABP B-46I/USOR 07132, and NSABP B-49) compared docetaxel plus cyclophosphamide versus anthracycline/taxane- based chemotherapy regimens (TaxAC). With 397 invasive DFS events, the 3-year invasive DFS rate was 91.7% for cyclophosphamide versus 92.4% for TaxAC. For triple-negative breast cancer (TNBC), it was 86.6% versus 89.6%, and for HR-positive disease it was 94.1% versus 93.7%, respectively.5

“The large trial was designed to see if we do get noninferior results with nonanthracycline therapy, and the answer is no,” said Tripathy. “We cannot say that it is OK to omit an anthracycline; there is still a bene t. What we probably should be doing is offering nonanthracycline therapy only in lower-risk cancers. Higher-risk cancers should probably be getting anthracycline-based therapy even though there are more side effects.” Neoadjuvant HER2-Positive Therapy In a phase III study presented at ASCO, researchers looked at lapatinib as a component of neoadjuvant therapy for HER2-positive operable breast cancer.6

View Conference Coverage
Online CME Activities
TitleExpiration DateCME Credits
Community Practice Connections™: How Do We Leverage PARP Inhibition Strategies in the Contemporary Treatment of Breast Cancer?May 31, 20191.5
Community Practice Connections™: A Better Way to Stop Pain: Paths Toward Responsible Postsurgical Pain Management for Patients With Breast CancerMay 31, 20191.5
Publication Bottom Border
Border Publication