Management of the Axilla in Early-Stage Breast Cancer: Ontario Health (Cancer Care Ontario) and the American Society of Clinical Oncology Joint Guideline

Guideline Objective

This clinical practice guideline was produced jointly by Ontario Health (CCO) and the American Society of Clinical Oncology. The aim of this work is to provide recommendations on the best strategies for the management, and on the best timing and treatment (surgical and radio-therapeutic) of the axilla in early-stage breast cancer. Specific objectives are: 1) To determine which patients with early-stage breast cancer require axillary staging; 2) To determine whether any further axillary treatment is indicated for women with early-stage breast cancer who did not receive neoadjuvant chemotherapy (NAC) and are sentinel lymph node negative at diagnosis; 3) to determine which axillary strategy is indicated for women with early-stage breast cancer who did not receive NAC and are pathologically sentinel lymph node-positive at diagnosis (after a clinically node-negative presentation); 4) to determine what axillary treatment is indicated and what is the best timing of treatment for women with early-stage breast cancer treated with NAC; and 5) to determine which are the best methods for identifying sentinel nodes.

Patient Population

Patients with early-stage breast cancer (i.e., stages I, IIA, IIB; and prognostic groups T1, T2, N0, N1mi, N1, M0; and primary tumour size ≤5 cm).

Intended Guideline Users

General surgeons, radiation oncologists, medical oncologists, and other clinicians involved in the management of women with early-stage breast cancer (e.g., pathologists, radiologists, oncology nurses, genetic counselors).

Research Questions

1. Which patients with early-stage breast cancer require axillary staging (i.e., SLNB, ALND, or US)?
2. For women with early-stage breast cancer who did not receive NAC, and are sentinel lymph node negative at diagnosis:
   1. Is further axillary treatment (i.e., radiation, or surgery) indicated?
   2. What sentinel node-negative patient subgroups are most likely to benefit from further axillary treatment with radiation therapy?
3. For women with early-stage breast cancer who did not receive NAC and are pathologically sentinel lymph node positive at diagnosis:
   1. Which axillary strategy is indicated?
   2. What sentinel node-positive patient subgroups are most likely to benefit from further axillary treatment either with radiation or with surgery or both?
4. For women who were treated with NAC:
   1. If the lymph node is negative at diagnosis, what axillary treatment (i.e., radiation or surgery) is indicated after chemotherapy?
   2. If the lymph node is positive at diagnosis, what axillary treatment (i.e., radiation or surgery) indicated after chemotherapy?
   3. When is the best timing for performing sentinel node excision: prior or following NAC?
5. Among patients with early breast cancer appropriate for axillary staging:
6. Is there a better identification rate with single or dual tracer?
7. Is there a better identification rate with US-guided SLNB or traditional SLNB?
8. Is there a better identification rate with US or SLNB?