Abstract P2-01-27: In patients with micrometastatic in sentinel lymph node biopsies, involvement of the non-sentinel lymph nodes cannot be predicted by clinicopathological variables

Abstract

Abstract Background: The Sentinel Lymph Node Biopsy (SLNB) procedure is recognised to be an accurate method of staging the axilla in patients with early stage breast cancer. There remains a debate as to whether patients with micrometastases should undergo completion axillary lymph node dissection (CALND). We aimed to assess the indicators for positive non-sentinel lymph nodes (n-SLN) following CALND. Methods: We retrospectively analysed our experience of SNLB between July 2008 to July 2013. A total of 1152 breast cancer patients underwent SLNB based on lymphoscintigraphy, intra-operative gamma probe detection, and blue dye mapping using 99mTc-nanocolloid and Patent Blue V injected peri-areola. Statistical analysis was performed using Fisher’s exact and c2 for categorical data. Results: Out of 1152 SLNB biopsies performed, 224 (19.5%) were positive for metastatic disease; macrometastases in 150 (67%), micrometastases in 72 (32%) and ITC in 2. CALND was not performed in 20 cases (9 macrometastases, 10 micrometastases, and 1 ITC), largely due to concerns regarding fitness for anesthesia. Macrometastases on SNLB were more likely to predict positive n-SLN on ANC {macrometastases; 39/141(27.7%) vs micrometastases; 9/62 (14.5%), p=0.029}. On univariate analysis, positive n-SLN in CALND for patients with micrometastases on SLNB was not predicted by grade (G0-G2; 6/43, and G3; 3/19, p=0.565), size of primary breast tumour (<40mm; 8/58, 340mm; 1/4, p=0.475), lymphovascular invasion (5/30 vs 4/31, p=0.503), age (<50 years; 3/24 vs 350 years; 6/38, p=0.496), or number of positive SLNB (all patients had <2 positive nodes on SLNB). Recurrences were detected in 4 patients, of which 1 was in a patient with micrometastases on SLNB. Out of the 4 recurrences, 3 were distant (liver and bone) and one was locoregional, with new disease in the contralateral breast). Conclusion In our series, 14.5% (9/62) of patients with micrometastases had positive n-SLB on CALND, which was not predicted by any clinicopathological characteristics. We have recently changed our practice toward not routinely offering CALND in patients with micrometastases, in keeping with current vogue. However, it is important to inform our patients that 14.5% of patients with micrometastases on SLNB may have positive n-SLN. Citation Format: Muhammad N Chauhan, Rajiv V Dave, Mauria Ghaus, Sana Ahmad, Craig Sayers, Zbigniew Kryjak, Deedar Ali. In patients with micrometastatic in sentinel lymph node biopsies, involvement of the non-sentinel lymph nodes cannot be predicted by clinicopathological variables [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-27.