M. L. Collins2, C. O’Donoghue1, W. Sun1, C. Laronga1, J. Zhou1, Z. Ma1, M. C. Lee1 1Moffitt Cancer Center,Tampa, FL, USA 2Morsani College Of Medicine,Tampa, FL, USA
Introduction: Sentinel lymph node (SLN) biopsy is the current prognostic tool for clinically node negative breast cancer patients. If the SLN reveals macrometastasis, axillary node dissection (ALND) is recommended. However, the use of ALND in patients with micrometastasis is debated. The objective of this study was to assess the utilization of ALND in the treatment of micrometastatic breast cancer.
Methods: An IRB approved, single-institution, retrospective study of a pooled dataset of breast cancer patients with micrometastatic disease on SLN biopsy pathology for incident, invasive breast cancer was performed. Patients diagnosed from 1999 – 2016 were identified via query of a single-institution NCCN breast cancer database as well as a prospective tumor board. Data collected included diagnostic and pathologic variables, surgery type, adjuvant treatment, recurrence, and outcomes. Neoadjuvant therapy cases were excluded. Demographics were summarized using descriptive statistics. Wilcoxon rank-sum and Kruskal-Wallis Test Fisher exact test were used.
Results: A total of 91 patients were diagnosed with micrometastatic nodal disease. 7 cases were ER/PR negative, and 5 cases were ER/PR, Her2Neu negative. 50/91 (54.9%) patients had an MRI preoperatively, and 34/91 (37.4%) patients had a preoperative axillary ultrasound; one patient was diagnosed by axillary FNA. The median age at diagnosis was 56 years (range 31-85); median follow up time was 47 months (range 0-203 months). The median number of resected SLN was 2 (range 1-8); 81/91 (89.1%) patients had intra operative touch prep of the nodes. On final pathology, 86/91 (94.5%) patients had 1 positive node, and 5/91 (5.49%) patients had 2 positive nodes. 43/91(47.3%) patients had ALND of which 36/43 (83.7%) were a second operation; 3/43 patients had additional positive nodes found at ALND. 7/91 (7.7%) patients had a recurrence, 5/7 local, including 1 axillary (patient declined ALND). 44/91 (48.4%) patients received radiation; 28/44 (63.6%) whole breast radiation, 16/44 (36.4%) chest wall radiation, and 20/44 (45.5%) also had directed nodal radiation.
Conclusion: Given that the risk of lymphedema after ALND ranges between 20-53%, the morbidity of ALND may far exceed the likelihood of detecting further nodal involvement in women with micrometastatic disease: 7% in this series. However, considering our small and highly selected single institution database, the decision to abandon ALND in patients with a micrometastatic SLNB needs further validation.
