- Patients must have evaluable or measurable disease and have shown unequivocal evidence for tumor recurrence or progression by MRI or CT scan. This scan should be performed within 14 days prior to registration and on a steroid dosage that has been stable for at least 5 days. If the steroid dose is increased between the date of imaging and the initiation of treatment, a new 20 baseline MR/CT scan is required. The same type of scan, i.e., MRI or CT must be used throughout the period of treatment for tumor measurement.