Abstract PD4-01: Preservation of axillary lymph nodes compared to complete dissection in T1-T2 breast cancer patients presenting 1-2 metastatic sentinel lymph nodes : A multicenter randomized clinical trial. Sinodar One

Surgical Management of the Axilla for Breast Cancer

This review discusses the contemporary surgical management of the axilla in patients with breast cancer. Surgical paradigms are highlighted by clinical nodal status at presentation and treatment approach, including upfront surgery and neoadjuvant systemic therapy settings. This review focuses on the increasing opportunities for de-escalating the extent of axillary surgery in the era of sentinel lymph node biopsy, while also reviewing the remaining indications for axillary clearance with axillary lymph node dissection.

Contemporary Axillary Management in cT1-2N0 Breast Cancer with One or Two Positive Sentinel Lymph Nodes: Factors Associated with Completion Axillary Lymph Node Dissection Within the National Cancer Database

BACKGROUND

Management of the axilla in patients with cT1-2N0 breast cancer with one or two positive (+) sentinel lymph nodes (SLNs) is often debated, especially in patients undergoing mastectomy. In 2018, the National Cancer Database (NCDB) began collecting the number of +SLNs, enabling identification of patients with one or two +SLNs for the first time.

METHODS

From the 2018 NCDB participant user file (PUF), all cT1-2N0M0 patients with one or two +SLNs were identified. The rates of completion axillary lymph node dissection (cALND) after breast-conserving surgery (BCS) and mastectomy were determined, and logistic regression was used to assess factors associated with cALND.

RESULTS

Of 10,531 patients with one or two +SLNs, cALND was performed in 807/6498 (12.4%) BCS patients and 1845/4033 (45.7%) mastectomy patients (p < 0.001). Factors associated with cALND in BCS were cT2 versus cT1 (16.0% versus 11.1%, p < 0.001), two versus one positive SLN (20.7% versus 10.8%, p < 0.001), and higher tumor grade (grade 3: 15.4% versus grade 1-2: 11.7%, p = 0.002). Factors associated with cALND among mastectomy were cT2 versus cT1 (48.2% versus 43.7%, p = 0.004), two versus one positive SLN (56.6% versus 42.8%, p < 0.001), younger age (age < 50 years: 49.0%, age 50+ years: 44.1%, p = 0.004), and Hispanic ethnicity (55.7% versus 45.1%, p = 0.001). After adjusting for pN category, adjuvant radiation was significantly less likely after mastectomy if cALND was performed (odds ratio (OR) 0.51, p < 0.001).

CONCLUSIONS

Omission of cALND with one or two +SLNs in BCS is common. Deescalation of axillary therapy in mastectomy is slower, with a cALND rate of 45.7% in 2018. With the recent updates to the National Cancer Care Network (NCCN) guidelines, we anticipate continued deescalation of axillary therapy in mastectomy patients.