Prediction of 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 52 patients with breast cancer who undergo surgical resection to single brain metastases and who received post-operative radiotherapy between the years 2010–2022. All clinical and dosimetric variables were analyzed to evaluate their impact on local control. A predictive model for local control was calculated. Results One year local control was 65.3%. HER-2 disease, size of initial tumor, time from initial surgery, total dose deliver and the type of lesion were all significant for local control. The most important variable was total dose deliver. A specific nomogram using 7 parameters for a prediction of local was computed. 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 of 5 fraction with a dose of 30Gy (BED4 > 70Gy) seem important for achieving local control and without increase toxicity.