[De-escalation in axillary breast cancer surgery: Real-life applications]

The indications for axillary lymph node dissection (ALND) have been reduced in breast cancer surgery. At the same time, maintenance treatments have become more complex. This paradox makes it essential to assess whether de-escalation might underestimate lymph node invasion, resulting in a loss of chance for patients eligible for these treatments. The aim is to determine the factors for lymph node invasion ≥4N+ in primary surgery, and for complete histological lymph node non-response in neoadjuvant chemotherapy, and then to assess the proportion of patients with an indication for ALND, and the proportion of patients eligible for enhanced maintenance treatment, in 2023. This is a single-centre retrospective study conducted at the Centre Antoine Lacassagne, involving patients treated for breast cancer with subclinical lymph node involvement between 2014 and 2020. In primary surgery, 62.9% had lymph node involvement <4N+. The predictive factor for lymph node involvement ≥4N+ was loss of ovality on ultrasound (P=0.01). After neoadjuvant chemotherapy, 45.7% had a complete histological lymph node response. MRI of the breast and axilla was the best predictor of this response (P=0.007). Twenty-nine percent of primary surgery patients were eligible for sentinel node therapy, with only one eligible for maintenance treatment. After neoadjuvant chemotherapy, 46% could have avoided ALND without compromising maintenance treatments. Under the new recommendations, 35% of patients could have avoided ALND. Ultrasound is the best preoperative examination for primary surgery. MRI is preferable for predicting response to neoadjuvant chemotherapy. There is no loss of chance for patients eligible for the new adjuvant treatments.