Selected Pathological Criteria That Predict Low Rates of Axillary Lymph Node Metastases Regardless of Patient Age: A Single Institution Study

BACKGROUND AND AIMS: Omission of sentinel node biopsy is increasingly offered to selected older women with cN0 low-risk breast cancer (BC). We hypothesized that some younger women might exhibit a low enough incidence of lymph node metastases to possibly justify excluding axillary surgery. METHODS: We statistically analyzed, using parametric and nonparametric tests as appropriate, multiple demographic and clinicopathologic variables in cT1-2 N0 M0 BC patients of all ages undergoing axillary LN excisional surgery from a long-term, prospectively maintained database. RESULTS: Patients with (816) and without (3617) LN metastases were compared. Although older patients were significantly (p < 0.0001) less likely to have LN metastases compared to younger patients, 3/61 (4.92%) of those < 50 years old with grade 1 tumors ≤ 1 cm in size (T1a and b) and no lymphovascular invasion had LN metastases compared to 30/504 (5.95%) ≥ 50. Patients aged 50 or older with Grade 2/3, < 1 cm, LVI-negative tumors had only 53/774 (6.85%) LN positive, compared to 19/131 (14.5%) in women < 50 with the same pathology. CONCLUSIONS: Women with grade 1, ≤ 1 cm invasive BCs, and no LVI had < 6% incidence of LN metastases regardless of age. Instead of excluding younger women from axillary node surgery de-escalation strategies, this study suggests that any woman with a tumor size ≤ 1 cm, Grade 1, and no LVI could be evaluated in prospective studies whose objective is to safely avoid axillary LN surgery.