Chief resident here. Yes, a CT C/A/P to see the tumor burden. Get Medicine or Oncology involved. If they had a seizure, then get Neurology involved. You can always quote Patchell's paper (
https://www.ncbi.nlm.nih.gov/pubmed/2405271) as justification for operating, but do you want to base your clinical decision on a study with 48 patients? Not me.
My practice is to:
1) have patient admitted (ICU vs neurosurgery vs medicine, depending on their clinical status and other active medical problems). There are benefits to having the patient on your service during their workup, but no always in the best interest of the patient if they have active medical issues, which can happen with metastatic cancer.
2) evaluate tumor burden with ct c/a/p
3) have oncology weigh in with prognosis (often times they don't know or can't comment, but I feel that a frank conversation between oncology and the patient is very important. Patients trust and respect you as a neurosurgeon, but I feel they'll trust you more if you involve an oncologist)
4) take 2-3 in account before recommending brain surgery