ASCO Updates Guidelines for Early Breast Cancer Based on TAILORx, MINDACT Trials

July 1, 2019

ASCO has updated its endorsement of a guideline regarding adjuvant systemic therapy decisions for early-stage operable breast cancer.

The American Society of Clinical Oncology (ASCO) has updated its endorsement of a guideline regarding adjuvant systemic therapy decisions for early-stage operable breast cancer. The update includes guidance on who might be able to avoid chemotherapy, among other decisions.

ASCO published an endorsement of the Cancer Care Ontario (CCO) guideline on the role of patient and disease factors in adjuvant systemic therapy in July 2016. Since then, results from two large randomized trials (TAILORx and MINDACT) have prompted the update, focused entirely on the question, “What risk stratification tools may be used in determining the utility of certain systemic therapies in patients with early-stage breast cancer?” The update was published in the Journal of Clinical Oncology.

Among the updates is the recommended methods by which treatment decisions are made. “Shared decision making between clinicians and patients is appropriate for decisions concerning adjuvant systemic therapy for breast cancer,” wrote the authors, led by N. Lynn Henry, MD, PhD, of the University of Utah Huntsman Cancer Institute in Salt Lake City. That shared process can include medical oncologists, pathologists, surgeons, oncology nurses, as well as patients and other caregivers.

More specifically, the update focuses on how Oncotype DX and MammaPrint assay scores should guide treatment decisions; all recommendations are specific to patients with breast cancer where HER2 is not overexpressed. For patients older than 50 years and whose Oncotype DX recurrence score is less than 26, as well as for patients 50 years and younger whose score is below 16, “there is little to no benefit from chemotherapy.” Endocrine therapy alone can be offered to these patients.

For younger patients with scores of 16 to 25, chemoendocrine therapy may be appropriate. All patients with an Oncotype DX recurrence score above 30 should be considered candidates for chemoendocrine therapy, and this treatment can be offered to patients with scores of 26 to 30.

The MammaPrint assay can be used to determine whether to withhold adjuvant chemotherapy in patients with hormone receptor–positive, lymph node–negative breast cancer, and in certain patients with lymph node–positive disease. The assay has only been found to be clinically useful in patients at high clinical risk, and so ASCO’s expert panel does not recommend its use in those determined to be at lower clinical risk.

Following the release of the TAILORx results, which was among the largest breast cancer trials ever conducted, Joseph A. Sparano, MD, of the Albert Einstein College of Medicine in New York, told Cancer Network that the results are helping refine some of the gray areas in this setting. “I think at this point, clinicians can make decisions and treatment recommendations with a much higher level of evidence-really, an unprecedented amount of evidence-and we have a greater degree of precision than we’ve ever had,” he said.