An 80 year old male with history of hypertension, IDDM, and CML presents with acute onset confusion and left-sided weakness. The patient has no signs of trauma and is currently afebrile. The patient's family states he has had progressively worsening fatigue, night sweats, intermittent fever, and bone pain for the past week. During your initial workup the patient's WBC result as 113 x 10^9/L. What is the definitive management for this patient's symptoms?