Daily highlights – 2

General Session 2 of the San Antonio Breast Cancer Symposium focused on surgical de-escalation and innovative radiation strategies in breast cancer. 

The BOOG 2013-08 phase III randomised trial evaluated omission of sentinel lymph node biopsy in clinically node-negative early breast cancer. Among more than 1,000 patients with cT1–T2N0 disease, omitting sentinel lymph node biopsy was non-inferior to standard surgery for five-year locoregional control. Most enrolled patients had low-risk features, such as small tumours, low grade, and hormone receptor positivity. These results confirm prior findings from the INSEMA trial and support omitting axillary surgery in carefully selected low-risk patients. Importantly, the study also showed that endocrine therapy is not mandatory to safely omit sentinel lymph node biopsy.¹

The AXSANA/EU-BREAST 3 trial addressed axillary management in patients who were initially node-positive but converted to node-negative after primary systemic therapy. The study compared axillary lymph node dissection with less invasive approaches, including sentinel or targeted axillary dissection. At three years, omission of full axillary dissection was non-inferior in terms of oncologic outcomes, supporting further de-escalation in this patient population.²

The final topic explored immune-priming radiation therapy combined with neoadjuvant immunotherapy. Results from the P-RAD and Neo-CheckRay phase II trials showed that giving 3 times 8 Gy to the primary breast tumour enhanced immune activation. Radiation increased T-cell infiltration, tertiary lymphoid structure formation, and PD-1 expression, particularly in immunologically cold tumours. These findings suggest radiation may enhance responsiveness to immunotherapy.³⁻⁴

Although these immune-priming strategies are still exploratory and not practice-changing, they provide a rationale for future trials investigating combined radiotherapy and immunotherapy approaches in breast cancer.