ABOUT THE AUTHORS
Affiliations: Dr. Rosenfeld is Adjunct Professor of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA; Ms. Albright is a Certified Registerd Nurse Practitioner at the University of Pennsylvania School of Medicine; and Dr. Pruitt is Associate Professor of Neurology at the University of Pennsylvania School of Medicine.
Conflicts of interest: The authors have nothing to disclose.
FIGURE 1 Pseudoprogression after chemoradiation. MRI of a biopsy-proven grade III astrocytoma before treatment (left panel). Three weeks after completion of chemoradiation, there is an increase in the size of the cystic component and enhancement (middle panel), which could be interpreted as tumor progression. After 4 cycles of post-radiation temozolomide, the right panel shows a decrease in size and enhancement, supporting the earlier imaging changes as reflective of pseudoprogression. All images are T1 post gadolinium with a 1.5 Tesla magnet.
FIGURE 2 Imaging changes with bevacizumab. This 57-year-old woman presented with a second recurrence of glioblastoma 2 years after chemoradiation and 6 cycles of adjuvant temozolomide and 6 months after 8 cycles of low-dose temozolomide. The images show post-contrast T1-weighted sequences (A, C, E) and fluid-attenuated recovery (FLAIR) sequences (B, D, F). Baseline images (A, B) show a left frontal mass with enhancement, edema, and some mass effect. Eight months later, after 4 cycles of bevacizumab (dosed every 2 weeks with 3 doses per cycle), there is decreased periventricular enhancement and edema (C) and improved FLAIR signal (D) but enlargement of the enhancing left frontal mass, which would meet standard definitions of tumor progression. The patient was neurologically stable and remained on treatment. Nine months later, after 5 additional cycles, she remained neurologically stable (and was not receiving corticosteroids). At this time, the mass has continued to increase in size (note: there is also invasion of the frontal sinus; E), with increasing FLAIR abnormality, likely reflecting a progressive infiltrating nonenhancing tumor (F).