ASCO and Ontario Health (Cancer Care Ontario) have collaborated to release a new clinical practice guideline on the management of the axilla in early-stage breast cancer.1
“A lot has changed in the past several years with regard to de-escalating the amount of treatment women are offered in the axilla without any guidelines to consolidate the evidence,” said Guideline Working Group Chair Muriel Brackstone, MD, PhD, of London Health Sciences Centre, London, Ontario. “We felt that this guideline would provide clinicians with direction as they navigate some of these changes.”
Muriel Brackstone, MD, PhD
The convened Working Group and Expert Panel conducted a review and evaluation of available scientific literature for the management of patients with early-stage breast cancer requiring axillary staging. Where existing evidence may have been lacking, Dr. Brackstone said, expert opinion and consensus were used to draft recommendations.
The recommendations included in the guideline are for patients with early-stage breast cancer: stage I, IIA, IIB, and prognostic groups T1, T2, N0, N1mi, N1, M0, and those with primary tumors of 5 cm or less.
Staging and Treatment Recommendations
The guideline includes recommendations that addressed five objectives. The first objective was to determine which patients with early-stage breast cancer required axillary staging. Here, the guideline recommended that patients younger than age 70 without significant competing comorbidities should undergo sentinel lymph node biopsy for axillary staging, and patients aged 70 or older with clinically node-negative invasive disease that is hormone receptor–positive and HER2-negative forgo sentinel lymph node biopsy.
“We wanted to base the treatment decisions on the patient’s clinical presentation at diagnosis; whether they are clinically node-positive or clinically node-negative,” Dr. Brackstone said. “If they are clinically node-negative with early-stage breast cancer, we don’t necessarily need to interrogate the axilla further with ultrasound and find microscopic disease. We will identify small amounts of disease in the lymph nodes by sampling them using the standard sentinel node procedure, rather than committing them to an axillary lymph node dissection simply because they are found to be lymph node–positive before surgery.”
The Working Group wanted to determine whether any further axillary treatment is indicated for women with early-stage disease who did not receive neoadjuvant chemotherapy and are sentinel lymph node–negative at diagnosis. For these patients, the recommendation is that clinicians should not recommend an axillary lymph node dissection for women who do not have nodal metastases; however, in select patients—for example those with medially or centrally located tumors—it is reasonable to offer the option of locoregional nodal irradiation.
The Working Group also provided recommendations for women who did not receive neoadjuvant chemotherapy but were sentinel lymph node–positive at diagnosis.
In this situation, clinicians should not recommend axillary lymph node dissection for women with early-stage disease who have one or two sentinel lymph node metastases and who will receive breast-conserving surgery with whole-breast radiotherapy. However, they noted that it is reasonable to offer the option for treating the axilla with radiotherapy in addition to breast or chest wall irradiation after surgery, particularly in patients with medial/central tumors and those with high-risk features (such as the triple-negative tumor subtype or high-grade disease). Locoregional nodal irradiation may be omitted in these patients if they have unilateral cancer of small size, favorable tumor features, clear margins, and one to three positive nodes.
Next, recommendations addressed what axillary treatment is indicated and the best timing of this treatment in women who undergo neoadjuvant chemotherapy. Patients who are initially node-negative and those with suspicious nodes deemed to be pathologically negative and were treated with neoadjuvant chemotherapy should receive sentinel lymph node biopsy at surgery as their axillary staging procedure, the Expert Panel recommended. Much more nuanced decision-making is required for patients who are initially node-positive. The patients who responded well to chemotherapy should undergo a sentinel lymph node biopsy as a restaging procedure, and those who did not should undergo an axillary lymph node dissection. Clinicians are advised then to treat both groups with locoregional nodal irradiation until any ongoing clinical trials provide data to the contrary. The Expert Panel recommended against performing lymph node sampling twice, before and after neoadjuvant treatment.
Finally, the guideline addresses how to determine the best methods for identifying sentinel nodes. Specific recommendations are given for using a single tracer with upfront surgery and dual tracer (and localizing clip where available) when surgery follows neoadjuvant chemotherapy.
Ongoing Trials
Dr. Brackstone acknowledged that there is still much ongoing research in this area that future guidelines or recommendations will have to consider. For example, the NSABP B51 trial (ClinicalTrials.gov identifier NCT01872975) and the Alliance A011202/MAC19 trial (NCT01901094) are looking into further de-escalation of axillary surgery for patients who are biopsy-proven lymph node–positive at diagnosis and become clinically node-negative after neoadjuvant treatment.
“These trials may show us that instead of having a knee-jerk reaction to do a complete lymph node dissection, these patients may only need additional radiation or no additional treatment at all,” Dr. Brackstone said.
REFERENCE
Originally published in ASCO Daily News. © American Society of Clinical Oncology. ASCO Daily News, July 21, 2021. All rights reserved.
