How would you treat a patient with HER2 positive CNS only progression on fam-trastuzumab which had previously progressed on tucatinib/capecitabine/trastuzumab, and has failed both SRS and WBRT?   

I would present or refer her case to a multidisciplinary tumor board to 1) review her MRI to confirm there is progression vs. therapy changes, 2) see if she is a candidate for resection or irradiation of the progressing lesion (possibly using bevacizumab to reduce risk of radiation necrosis), and 3)...