Breast Oncology Research Updates

This review discusses how increasing use of neoadjuvant systemic therapy (NAC) in breast cancer is enabling response-adapted de-escalation of locoregional treatment. It summarizes emerging practices and trials evaluating omission of sentinel lymph node biopsy after NAC in selected cN0 patients, use of sentinel lymph node biopsy alone (and potential omission of regional nodal irradiation) for cN+ patients who achieve nodal pathologic complete response, and radiation adjustments including omission of tumor-bed boost in exceptional responders and use of premastectomy radiotherapy to facilitate reconstruction.

Pooled analysis of 18 phase II/III trials including 3,430 early-stage (IB–III) triple-negative breast cancer patients with pathologic complete response (pCR) found that neoadjuvant immune checkpoint inhibitor (ICI) plus chemotherapy improved event-free survival versus chemotherapy alone (HR 0.67, 95% CI 0.50–0.89; p<0.01) but did not significantly change overall survival (HR 0.84, 95% CI 0.50–1.41; p=0.51). Use of platinum or anthracycline-containing regimens did not significantly affect EFS or OS, and adjuvant ICI provided no EFS or OS benefit among patients who achieved pCR after ICI.

In a Phase I trial of a Th1-selective plasmid-DNA tri-antigen vaccine targeting IGFBP-2, HER2, and IGF-IR with GM-CSF in 32 participants with non-metastatic breast cancer, three monthly intradermal doses (150, 300, 600 µg) produced only grade 1–2 related adverse events with no dose-level differences. All dose levels were immunogenic (responders: 70% at 150 µg, 67% at 300 µg, 40% at 600 µg), and the 300 µg dose maintained Th1 antigen-specific responses at 6 months and was selected for Phase II study.