Introduction:

The current recommended management for patients with involved lymph nodes at diagnosis of breast cancer is to perform an axillary node dissection after receiving neoadjuvant chemotherapy (NAC), regardless of response. A number of studies have proposed de-escalation of this practice by performing sentinel node biopsies and targeted axillary dissections in those with response to chemotherapy. We have audited our practice to assess the safety of introducing management change.

Methods:

Cancer data was collected between 2014 and 2018 for patients who had NAC and further selection criteria for those with lymph node involvement at diagnosis and subsequently underwent NAC. Assessment of radiological response at NAC completion, tumour hormone receptors and HER2 status along with axillary nodal response on final histopathology were reviewed to assess whether patients can be stratified to less extensive axillary management.

Results:

290 patients underwent NAC, 60 of whom had nodal involvement at diagnosis:

- All had USS axilla, MRI at baseline and completion of NAC

- All 60 node positive patients underwent axillary clearance, as per current local protocol

- Out of those 60 node positive patients, 39 had breast conserving surgery, whilst 21 patients had mastectomy

- 20 (33%) patients showed complete radiological response (CRR) on MRI in both breast and nodes

- 23 (38%) patients achieved pathological complete response (PCR) in their nodes

- 17 patients showed both CRR and PCR

- 4 patients showed CRR but did not achieve PCR:

o patient 1: 1 macromet / 7 nodes - NEG/NEG/NEG

o patient 2: 1 micromet / 14 nodes - POS/POS/POS

o patient 3: 7 macromet / 10 nodes - POS/POS/NEG

o patient 4: 5 macromet / 19 nodes - POS/POS/NEG

- Large volume of nodal disease remained in 2 patients with POS/POS/NEG despite CRR

Conclusion:

MRI can be safely and reliably used in patients who show CRR with TNBC and HER2+ cancers to select patients for de-escalating axillary surgery. Caution in those patients with POS/POS/NEG cancers as MRI may show CRR but large volume disease in nodes may still persist. Further prospective audit of de-escalating treatment will be essential to ensure locoregional control and long-term disease-free survival outcomes.

Citation Format: Nagy ES, Whisker L, Asgeirsson K. Can we select patients suitable for targeted axillary dissection after neoadjuvant chemotherapy who originally presented with involved axillary nodes? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-27.