Abstract P2-18-05: Axillary nodal burden in patients with a positive pre-operative ultrasound guided fine needle aspiration cytology

Abstract

Abstract Introduction Recent years have seen a dramatic shift to more conservative management of the axilla and the presence of a positive sentinel lymph node biopsy does not now automatically mandate an axillary clearance. This is based largely on data from the American College of Surgeons Oncology Group (ACOSOG) Z11 study, which failed to demonstrate a difference in local recurrence or overall survival when an axillary clearance was omitted in a highly selective group of patients with a positive sentinel lymph node. However, the presence of a positive pre-operative ultrasound guided axillary FNAC(Fine Needle Aspiration Cytology) may be representative of a higher burden of axillary disease. Aim Therefore, the aims of this study were firstly to quantify the actual nodal burden in breast cancer patients with a positive pre-operative ultrasound guided axillary FNAC and secondly to identify the number of patients who may have been spared an axillary clearance based on Z11 eligibility criteria. Methods A retrospective review of a prospectively maintained database within a tertiary breast cancer referral centre was performed. All patients with a positive pre-operative axillary FNAC were identified within a five year period (2007 – 2011). Demographic, tumour and biological characteristics and final nodal status were analysed. Eligibility for randomisation according to the Z11 criteria was assessed based on the final pathology and the number of patients who could have been spared an axillary clearance was identified. Results A total of 360 patients were identified with a positive axillary ultrasound guided FNAC. Sixty-three patients had no axillary surgery and three patients had recurrent disease, leaving a total of 294 for analysis. The mean age was 56 years (range 22 – 87). The mean size of the tumour was 31.3mm (range 4mm – 132mm) and the majority were an invasive grade 3 (57%) ductal carcinoma (84%). Luminal A (63%) was the commonest sub-type. The mean number of nodes removed at axillary clearance was 24 (range 7 – 58) while the mean number of positive nodes excised was 6 (range 0 – 47). Of these, the mean number of level I positive nodes was 4, level II was 1 and level III nodes was <1. Overall a total of 78 patients had less than three positive nodes identified in the axilla and potentially may have been eligible for the Z11 study. However, when patients who had a mastectomy, neo-adjuvant chemotherapy were excluded and the presence of extra-capsular nodal involvement was accounted for only 19 (6.4%) patients may have been spared an axillary clearance. Conclusions The presence of nodal positivity on a pre-operative FNAC is associated with a higher burden of axillary disease. Only a minority of these patients would be able to avoid an axillary clearance in the setting of the recent Z11 study. Performing an axillary ultrasound and FNAC of suspicious nodes allows patients to avoid an unnecessary sentinel lymph node biopsy and proceed directly to an axillary clearance. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-05.