Oncologic First Events in Breast Cancer Patients After Targeted Axillary Dissection

Currently, targeted axillary dissection (TAD) is used in many centers as an alternative to axillary dissection for patients with lymph node metastases at diagnosis who receive neoadjuvant treatment. This allows patients to benefit from an axillary pathologic complete response rate as high as 60% during neoadjuvant treatment. Although the false-negative rate for TAD is low, data on oncologic outcomes are sparse and with limited follow-up time only. The study aimed to determine regional nodal recurrence and overall survival in a cohort of patients receiving TAD after neoadjuvant treatment.

Prospective follow-up data on cN1-3 breast cancer patients receiving TAD with ypN0 lymph nodes after neoadjuvant treatment were collected from the Danish Breast Cancer Group Database. The patients received surgery between 2016 and 2021. No patients had completion axillary dissection. Data were left-truncated and analyzed with the cumulative incidence function and competing risk approach and Kaplan-Meier methods. The main outcomes were 5-year regional nodal recurrence and overall survival.

Among 283 patients with ypN0 status when staged by TAD, the 5-year regional nodal recurrence rate was 1.1% (95% confidence interval [CI], 0.30-2.9%). This corresponded to three regional nodal recurrence events, in which all patients had synchronous distant metastases. The 5-year overall survival rate was 95.1% (95% CI 92.4-98.0%).

The low rate of regional nodal recurrence suggests effective long-term regional control and good overall survival for patients receiving TAD without axillary lymph node dissection.