Abstract P1-01-07: Pre-operative selection of patients with limited disease of the axilla using ultrasonography of the axilla: Might additional lymph node dissection (ALND) be safely omitted in the future?

Abstract

Background: The sentinel lymph node biopsy (SLNB) procedure is the method of choice for the identification and monitoring of regional lymph node metastases in patients with breast cancer. In the case of a positive sentinel node additional lymph node dissection is still warranted for regional control, though 40-65% have no additional axillary disease. Recent studies showed that after breast-conserving surgery, SLNB and adjuvant systemic therapy there is no significant difference between recurrence-free interval and overall survival if there are 2 or less positive axillary nodes. Purpose: Preoperative identification of patients with limited axillary disease (≤ 2 macrometastases) using ultrasonography (US). Method: Between January 2007 and August 2011, data from 1103 consecutive primary breast cancer patients who underwent surgery in our hospital were collected into a single database. Patients were selected by clinical tumours smaller than 50mm (cT1-2), no palpable adenopathy (cN0) and a maximum of 2 SLNs containing macrometastases. The variable of interest was ultrasonography of the axilla. The population was divided into two groups: the group with 2 or fewer positive nodes and the group with more than 2 positive nodes in the axilla after ALND. Results: After selection, 1060 patients remained of which 102 (9.6%) had more than 2 positive axillary nodes on SLNB or ALND. Selected by unsuspected US, the chance of having more than 2 positive lymph nodes is substantially lower (4.2%). This is significant on univariate and multivariate analysis. The chance of more than 2 positive lymph nodes was 12.8 times as big in case of a positive axillary US. When we select this subgroup even further by excluding the patients with extra capsular extension (ECE) on SLN, the chance of more than 2 positive lymph nodes is only 2.6%. Subdivided by clinical tumour size the chances are 0.96% in case of cT1 tumour and 7.0% in case of a cT2 tumour. For pathological T-status the numbers are respectively 0.87% en 5.0%. For pT1-2 this is 2.2%. Conclusion: The risk of more than 2 positive axillary nodes is relatively small in patients with cT1-2 breast cancer. Ultrasonography of the axilla helps in further identifying patients with a minimal risk of additional axillary disease, putting ALND up for discussion. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-01-07.