Evaluation
Laboratory tests (complete blood counts and basic metabolic panel) were obtained weekly, a physical examination was performed at every clinical visit with the medical oncologist, and contrast-enhanced brain MRI was performed every 4 weeks.
Neuroradiologic response following treatment was determined by response assessment in neuro-oncology (RANO) criteria (23). Complete response (CR) was defined as the disappearance of all contrast-enhancing tumor or non-enhancing tumor, as defined on MRI FLAIR sequence, on consecutive MRIs at least 1 month apart, with the patient off corticosteroids. Partial response (PR) was defined as a >50% reduction in the size of tumor derived by the sum of cross-sectional radii measured by the contrast enhanced MRI and the MRI FLAIR sequence on consecutive MRI scans at least 1 month apart, with a stable or decreased corticosteroid dose. Progressive disease (PD) was defined as a greater than 25% increase in the size of tumor on either the contrast enhanced MR or FLAIR tumor, or presence of new lesions. Stable disease (SD) was defined as all other situations and required a confirmation MRI one month after documenting best response. Patients were continued on ICI until documentation of PD or unacceptable adverse effects (AE) at which time patients either discontinued ICI, had bevacizumab added to their regimen, or were offered alternative therapy.
PFS and OS were defined as the time from the first day of treatment with ICI until progression of disease or death, or at date of last follow-up. AE were retrospectively determined for all patients and tabulated using Common Terminology Criteria for Adverse Events version 5.0.