Hypofractionated Radiosurgery Re-Irradiation in Large Solitary Brain Metastasis from HER2 Positive Breast Carcinoma

In improved therapeutic capabilities, late progression of locally advanced HER2 positive breast cancer (BC) is increasingly diagnosed after complex treatment by expression of late solitary brain metastasis (BM). We present a 35-year-old woman with left invasive ductal BC /pT2N1M0, grade G3 with positive estrogen, progesterone and HER2 receptors expression. Complex treatment was carried out, including radical mastectomy with axillary dissection followed by adjuvant treatment- chemotherapy (Ch), radiotherapy (RT), targeted therapy (TT) with trastuzumab and endocrine therapy with LHRH agonist plus tamoxifen. After 8 years a single brain metastasis has been found, extirpated and histologically verified. Postoperative whole-brain radiotherapy (WBRT) up to total dose (TD) 25 Gy with daily dose (DD) 2,5 Gy and boost in brain metastasis up to biologically effective dose/BED 49,5Gy was conducted. August-October 2020 after 1 year of WBRT, against the background of complex treatment with 2 targeted agents/ trastuzumab/pertuzumab and endocrine therapy, CT visualized elevated vasogenic peritumor edema with the progress of the mass effect. The only therapeutic alternative was re-irradiation of brain metastasis by hypofractionated radiosurgery (HFRS). The purpose of this article is to present the efficient healing combination of targeted therapy and HFRS re-irradiation in late solitary BM from HER2 positive BC, not only in terms of local control but also on prolonged survival.