The feasibility of a randomised controlled trial for the axillary management of a select group of invasive breast cancer patients: SLNB vs. no-SLNB

Abstract

The results of ZOO11 have shaken our thinking and approach for the axillary management of small invasive breast cancers where the incidence and burden of axillary metastasis would be much less than that of ZOO11 population. The traditional approach of sentinel lymph node biopsy (SLNB) for "all invasive cancers" is challenged because of the diminishing role of axillary lymph nodes (ALNs) status in guiding the adjuvant systemic therapy. Certainly this raises the question of whether SLNB can be avoided in a select group of patients without compromising clinical outcomes. The aim of this study was to identify such a group of patients in whom SLNB is no longer required. Patients with breast cancers ≤2 cm in size and clinically negative axilla who underwent breast conserving surgery (BCS) and SLNB were identified. Patients were divided into different groups; incidence of ALNs metastasis, further non-SLNs metastasis and a total number of tumour positive ALNs of ≥4 were determined. A total of 194 patients met the criteria; incidence of tumour positive SLNs, further non-SLNs metastasis and a total number of tumour positive ALNs of ≥4 varied between different groups and was 9.3-15.5 %, 0-35 % and 0-2.6 %, respectively. Patients with T1b, grade 1-2 tumours had less than 5 % risk of ALNs macrometastasis. It is possible to identify a group of patients whose burden of axillary disease is acceptably low enough that SLNB can be avoided. Feasibility of a non-inferiority randomised controlled trial (RCT) in a select group of patients with or without SLNB has been explored to compare the distant disease free, disease free and overall survival and axillary relapse rate (ARR).