Feasibility of breast conserving surgery alone in HER2-positive exceptional responders to neoadjuvant systemic therapy.

ABSTRACT

It is unknown if radiation therapy provides additional benefit among patients who achieve pathologic complete response (pCR) following neoadjuvant systemic therapy (NST). We sought to assess feasibility of radiation omission after breast conserving surgery in early-stage, node-negative, HER2+ breast cancer patients with pCR after NST. This was a single-arm study of women 30 years and older with cT2N0 disease based on imaging. Six patients were followed with mammography or MRI every 6 months following surgery. The median age of patients was 58 years (IQR 46-66). At a median follow-up of 31.6 months (range 21-40 months), no Ipsilateral Breast Tumor Recurrences (IBTR) were identified. This approach was found to be feasible, warranting further study in larger prospective trials.