Most of our limited background is with patient-members who were in recurrances and/or had multiple treatments already. You still have more initial potential to have dramatic response to immune treatments or chemo, albeit CSF penetration adds uncertainties. For radiation with that much load and fine targeting, I would suspect the most advanced proton or carbon ion center might be a possibility, SBRT or IMRT being conventional with more limitations.
In this decade, medical miracles are more occasionally being issued, but you have to take decisive steps forward. My wife is a near miracle in others' eyes. For me it was more like a scattered cookbook of misplaced recipes unscrambled that represents common problems in mCRC and expands on recommendations from Life Extension Foundation.
One member here, sleen, got a miracle result with an experimental immune treatment.
A % of people match the specific criteria for PD-1 inhibitors with big responses.
Others have occasionally had huge responses to their chemo.
My wife's huge immune response is most important as an immediate step, for its "first aid - first day" aspect with easy availability, "over the counter", and "niceness". Something that got a huge response immediately, doable yourself with supplies from Walmart and health stores, appears broad spectrum, and did not disturb any chemo or surgery options later. In fact, it combined so well with basic 5FU oral chemo, to the point heavy chemo has been unnecessary. Because of my particular personal and technical background, we had a place to start, and my wife didn't hesitate. But most people never start or do 1/4.
Also I know we've used
types and dosages of cancer inhibiting vitamins that penetrate the blood brain barrier. e.g. IV dehydroascobate content in sodium ascorbate (C), oral menaquinone-4 (menetetrenone, a human version of vit K2 with a transport protein), 60,000 iu cholecalciferol (vitamin D3).
A conventional 2017 paper:
Spine Oncology—Metastatic Spine Tumors