Hypophysectomy by Stereotactic Radiosurgery for Cancer-Related Pain

Inclusion Criteria:

* Age ≥ 18 years old on the day of signing informed consent and willing and able to sign a written informed consent.
* English fluency in order to complete PROs and neurocognitive assessment
* Pathologic or cytologic confirmation of malignancy.
* Poorly controlled intractable nociceptive or mixed pain limiting function or quality of life. Participants must have exhausted or not a candidate for standard of care pain control measures such as opioids, injections/ablations, conventional radiation therapy, or surgical intervention with a curative intent and pain limiting function that affects the participants quality of life in the judgment of the treating physician. Refractory status will require at least consultation and two follow-up visits with pain specialists (pain management or supportive care).
* ECOG performance status of 0-3.
* Life expectancy is greater than 4 weeks and less than 1 year in the treating physician's judgment.

Exclusion Criteria:

* Participants with prior cranial or head/neck radiation where cumulative organ-at-risk dose constraints cannot be achieved (see section 4.2).
* Inability to have an MRI of the brain for reasons such as a non-compatible bioimplant that could be displaced during MRI, shrapnel embedded (such as from war wounds), metal workers, and machinists (potential for metallic fragments in or near the eyes).
* Expressions of pain due to depression, delirium or addictive behavior
* Participants who are pregnant.
* Known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the study in the judgment of the Investigators.