Razi Sitt

Impact of Resecting Radiation Necrosis and Pseudoprogression on Survival of Patients with Glioblastoma

INTRODUCTION Radiation necrosis (RN) and pseudoprogression are known as postradiation treatment effects and may simulate tumor progression. The disease course of glioblastoma patients who had developed RN and the impact of resecting RN on survival have not been evaluated. This study examines the clinical course of patients considered candidates for repeat surgery for a recurring brain mass proven to be RN and compared these with patients who had true tumor recurrence at surgery. METHODS Of 159 patients with glioblastoma who were reoperated on because of a presumed recurrent tumor requiring repeat surgery, 18 had RN as the major component of the resected mass. The characteristics and outcome of these 18 patients were retrospectively analyzed and compared with patients in whom active and bulky tumor was found during surgery. RESULTS Radiation necrosis occurred significantly earlier than true tumor recurrence. Patients with RN harbored larger lesions and were significantly more symptomatic before the second surgery. Most patients with RN who underwent GTR of the lesion in the second operation experienced faster resolution of the surrounding edema compared with patients who underwent STR or biopsy only. There was no significant difference in survival between the 2 groups. CONCLUSIONS These data provide an opportunity to examine the clinical course of a selected group of patients with histologically verified RN. Although RN is associated with more severe neurologic symptoms that improve after surgery, its occurrence or surgical removal carries no survival advantage compared with patients who undergo a repeat operation for true tumor recurrence.

BMET-11SURGICAL RESECTION OF CEREBRAL METASTASES LEADS TO FASTER RESOLUTION OF PERI-TUMORAL EDEMA: A QUANTITATIVE ANALYSIS

BACKGROUND: Surgical resection and stereotactic-radiosurgery (SRS) are valid treatment options for selected patients with brain-metastases. The desired rate of resolution of the tumor-associated edema may play a role in the decision making process. However, the dynamics of edema resolution with each modality has not been well characterized. METHODS: Of 646 patients treated at our center for brain metastases between 2010-2014, we retrospectively identified 70 patients (100 metastases) who underwent either surgery or SRS for brain metastasis, and had sufficient clinical data, and radiological follow-up to be included in this study. Individual volumetric measurement of the tumor and edema before, and three months after treatment, was performed. RESULTS: Forty-six surgical cases were compared to 54 cases treated with SRS. As expected, the volume of the tumor and surrounding edema were significantly higher in the surgical group compared to SRS. However, resolution of edema was significantly superior in the surgical group (p < 0.0001). After a matching process based on the propensity of a patient to receive SRS, a nested cohort of 40 patients was analyzed (mean-maximal diameter:21.5mm vs. 18.8mm for surgery and SRS, respectively). At diagnosis, edema volume, but not tumor volume was significantly higher in the surgical group. Three months after treatment, the resolution of edema tended to be much more prominent in the surgical group (74.2% vs.18.8% improvement, p = 0.1). Steroid consumption was significantly higher in the SRS group (p = 0.02). No difference in the incidence of new neurological deficits after treatment was found between the groups. CONCLUSIONS: Resolution of tumor-associated edema in medium sized brain metastases tended to be more prominent after surgical resection compared to SRS. Irradiated patients required a significantly higher dose of steroids. Accordingly, when both treatment options are suitable, surgery appears to induce a faster resolution of edema and perhaps may alleviate edema-induced deficits faster in patients with brain metastases.