NCCN Guideline Updates in HR+ Breast Cancer: Focus on Extended Adjuvant Therapy

In a recent OncView™ discussion, Lee S. Schwartzberg, MD, executive director of West Cancer Center and chief of the Division of Hematology & Oncology at The University of Tennessee Health Science Center in Memphis, addressed the National Comprehensive Cancer Network (NCCN) Guideline updates for hormone receptor (HR)-positive breast cancer, the use of extended adjuvant therapy for this disease, and the role of genomic assays in this therapy.

Schwartzberg explained that adjuvant endocrine therapy benefits breast cancer patients who are HR-positive, whether they have received chemotherapy or not; it is typically given for 5 years and is generally well tolerated. He highlighted that the therapy can have a carryover effect, working 5 years beyond the end of treatment. Moreover, trials in the 1990s and early 2000s showed that extending therapy beyond the initial 5 years can benefit patients modestly. Since these trials, clinicians have tried to determine which patients benefit most from extended adjuvant therapy, to minimize the toxicity of extended therapy, and to improve invasive disease-free survival.

Schwartzberg noted that newer genomic assays help clinicians to determine the prognostic and predictive value of adjuvant therapy. These assays look at an expression panel of genes in the tumor, help clinicians to make decisions about upfront chemotherapy, and are used broadly. However, he added, genomic expression profiles are not used to make decisions regarding adjuvant endocrine therapy because this therapy is typically offered to any patient who is HR-positive.

“I have used genomic assays since they first came on the scene, and I have found them extremely helpful over the years. That said, I don’t use them in every single patient with early-stage breast cancer,” Schwartzberg said.

He added that the NCCN recognizes several genomic assays, all of which are prognostic and some of which are predictive for chemotherapy. Moreover, Schwartzberg noted, the NCCN has expanded its genomic assay recommendations to include the Breast Cancer Index (BCI), which is prognostic and can predict the benefit of extended adjuvant endocrine therapy for a patient. The NCCN bases these updates upon recent clinical trial data, including those from the RxPonder and MINDACT trials (NCT01272037 and NCT00433589).

Schwartzberg noted that the NCCN guidelines accurately reflect the value of genomic assays, which helps clinicians to make decisions about extended adjuvant endocrine therapy. Such decisions can be especially difficult for patients at intermediate clinical risk for recurrence.

Schwartzberg concluded by emphasizing the value of genomic assays for patients with early-stage HR-positive breast cancer: “I have to underscore…that the majority of these patients do extremely well today because we have the tools now to know when to give them chemotherapy, when to give them adjuvant endocrine therapy, and when to give extended adjuvant endocrine therapy.”

REFERENCE

NCCN. Clinical Practice Guidelines in Oncology. Breast cancer, version 5.2021. Accessed July 17, 2021. https:// www.nccn.org/professionals/physician_gls/pdf/breast.pdf

Editor’s Note: Interview quotes slightly modified for readability

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