What impact local failure for post-operative radiotherapy of resected brain metastases in breast cancer patients?

Background Single brain metastasis surgical resection remains an effective treatment for brain metastases. However, surgery alone associate with a high rate of local failure. The current guidelines recommend radiation to surgical cavity. The recommended dose for brain cavity after surgery remain to be define as most guidelines gives a very general suggestion about the dose and fractionation. The aim of this study was to determine what variable influence local control in this specific population. Methods Retrospective analysis of 62 patients with breast cancer who undergo surgical resection to single brain metastases and who received post-operative radiotherapy between the years 2011–2022. All clinical and dosimetric variables were analyzed to evaluate their impact on local control. Results One year local control was 70.9%. HER-2 disease, size of initial tumor, time from initial surgery, total dose deliver, inclusion of corridor and type of lesion were all significant for local control. Patients with HER-2 positive disease had higher local control rate without any difference in other variables. Conclusion Brain metastases from breast cancer remain a life-threating condition. Surgery plays a critical role in the treatment of large symptomatic brain metastases for which Post-operative radiotherapy is essential. Choosing a regime with a dose of more then 40Gy (BED) seems important for achieving local control and without increase toxicity. Different biology and systemic therapy options can differentiate Breast cancer population after brain surgery for metastatic disease. A larger prospective trial is needed to addressed the question whether lower dosage can be use in HER-2 positive disease.