Abstract P3-01-13: FNAC: A predictor of final number of involved nodes at axillary clearance

Abstract

Abstract BACKGROUND: A vital part of pre-operative breast cancer assessment is axillary staging. Fine needle aspiration cytology (FNAC) is performed on clinically or radiologically positive axillary nodes in breast cancer. Our study looks at the sensitivity of performing FNAC in these patients and whether positive FNAC of axillary nodes can predict the final number of diseased nodes on completion axillary clearance (ANC). METHODS: All primary breast cancer patients undergoing FNAC between Oct 2009 to Oct 2011 were identified from electronic computer records. Data was collected on FNAC positivity, whether sentinel lymph node biopsy (SLNB) was performed, total number of nodes harvested at ANC and also the total number of diseased nodes at ANC. Patients who underwent neoadjuvant chemotherapy after a positive FNAC were analysed separately. RESULTS: Of the 230 patients who underwent FNAC, 130 were positive (56.5%). Of those who had a negative FNAC, 32% had a positive SLNB. We compared the ANC results of those who were FNAC positive (Group 1) with those who were FNAC negative but SLNB positive (Group 2). There was no significant difference in the mean number of harvested nodes at ANC between the two groups (mean= 17, p=0.14 on t-test). There was a significant difference in the number of diseased nodes in group 1 (mean = 7 nodes) compared with group 2 (mean = 3 nodes). In group 1, 56% of patients had 4 ≥ diseased nodes compared with 8.5% of patients in group 2. Neoadjuvant chemotherapy was given to 28 patients with a positive FNA. In this cohort, the mean number of positive nodes at axillary clearance was 2 and 10 % of patients had 4≥ diseased nodes on ANC. There was no significant difference in mastectomy versus breast conserving surgery rates between FNA positive and negative patients (p= 0.28 on Chi Square). The sensitivity of performing an FNAC was 81% in this study. Outcome of Patients undergoing Axillary Fine Needle Aspiration Cytology Group 1:FNAC positiveGroup2: FNAC negative, SLNB positive Mean No Harvested Nodes at ANC1816p=0.14Mean No of diseased nodes at ANC73p<0.05% of Patients with 4 or more diseased nodes at ANC568.5p<0.05% of Patients who had Breast Conserving Surgery5453p=0.28Key: FNAC:fine needle aspiration cytology, SLNB: Sentinel lymph node biopsy, ANC: Axillary clearance CONCLUSION: This study provides a predictor of the number of diseased axillary nodes in those with positive FNAC preoperatively. Over 50% of patients with a positive FNA have four or more diseased nodes compared with less than 10% in the FNAC negative but SLNB positive group. After neoadjuvant chemotherapy, FNA positive patients have a similar disease burden in the axilla as the FNAC negative but SLNB positive patients. This information can help to guide pre-operative discussions on the likely disease burden and need for adjuvant therapies such as chemotherapy and radiotherapy. Being able to predict the need for radiotherapy in particular can guide surgical decisions regarding type and timing of reconstructions to reduce the risk of surgical complications. Citation Format: Khan A, Hussain N, Irvine T. FNAC: A predictor of final number of involved nodes at axillary clearance [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-01-13.