Breast reconstruction and neoadjuvant radiotherapy (BRENAR) - study protocol for a multicenter, prospective, single-arm pilot study.

Background: Over the past decade, post-mastectomy radiotherapy (PMRT) is indicated more frequently in breast cancer treatment, especially in patients with involved axillary lymph nodes. However, PMRT is associated with high complication rates and less satisfactory cosmetic results when combined with immediate breast reconstructions. This has led to ongoing controversy regarding breast reconstruction and radiotherapy, often postponing the reconstruction until long after PMRT has been completed. Preoperative radiotherapy, also known as neoadjuvant radiotherapy (NART), is emerging as a safe and promising alternative with the potential to allow immediate reconstruction without the negative effects of radiotherapy on the reconstructed breast. However, data on the complication rates and patient-reported outcomes (PROs) after NART followed by mastectomy and breast reconstruction are still limited.

Methods: This is a multicenter, prospective, single-arm pilot study including breast cancer patients requiring mastectomy and PMRT, who desire immediate breast reconstruction, either implant-based or autologous. The primary objective is to assess complications three months after the last planned reconstructive surgery. The secondary objectives are to evaluate patient-reported health-related quality of life (HR-QoL), patient- and physician-reported cosmetic results, and pathological response.

Discussion: The primary outcome of this pilot study is to provide further evidence to determine whether NART is a viable alternative to PMRT in terms of complication rates when combined with immediate breast reconstruction. The secondary outcomes will enhance our understanding of patients' HR-QoL and cosmetic outcomes. If NART proves to be a safe alternative, this pilot study will lay the foundation for a national multicenter randomized controlled trial to evaluate long-term HR-QoL and oncological outcomes.