ThP1.2 - Management of breast cancer sentinel lymph node macrometastasis in the axilla; audit of current unit practice and evaluation of factors that influence patient management Free

Detection of sentinel lymph node (SLN) macrometastasis for breast cancer no longer mandates further axillary surgery. Association of Breast Surgery (ABS) guideline provides recommendation to optimise patient management. It also acknowledges management uncertainties in specific patient groups. We aimed to examine our unit practice against national guideline and evaluate potential factors that influence axillary management.

Retrospective analysis of prospectively maintained electronic database determined clinico-pathological characteristics on patients diagnosed with SLN macrometastasis (n=127) at the Leeds Breast Unit (2020-2022). Axillary management was compared against ABS guideline.

56 (44.1%) received completion axillary node clearance (cANC), 37 (29.1%) axillary radiotherapy (aRT), and 34 (26.8%) no further axillary treatment. 80.3% had one macrometastasis. As per guideline, all patients who had >3 macrometastasis (n=10) underwent cANC. Type of breast surgery (mastectomy vs. breast conserving surgery; BCS) did not affect further axillary treatment rate (76.7% vs. 70.1%). Type of further axillary treatment varied with cANC commonest for mastectomy patients (78.3%) and aRT commonest for BCS patients (57.4%). In contrast to the guideline, 58% of post-menopausal BCS patients with ER+HER2- T1 tumours (n=12) received further axillary treatment. Where guideline stated management uncertainty, further axillary treatment was frequent; pre-menopausal patients (82%), T2 tumours (73%), lymphovascular invasion (74%), and extranodal spread (77%).

Our unit’s SLN macrometastasis management is mostly in line with national guideline but further work is required to avoid overtreatment. Where management uncertainty exists, patients commonly received further axillary treatment. Further research is required in these patient groups to optimise axillary management.