Corticosteroid-Induced Regression of Glioblastoma: A Radiographic Conundrum

Objective: The purpose of this study was to evaluate variations in the regional incidence of glioblastoma in US adults in 2004–2013. Study Design and Setting: We evaluated 24,262 patients with primary glioblastoma. Data were categorized based on geographic regions that included different SEER registry sites as follows: (1) Northeast: Connecticut, New Jersey (3,977 patients); (2) South: Kentucky, Louisiana, Metropolitan Atlanta, Rural Georgia, Greater Georgia (excluding AT and RG) (5,212 patients); (3) North Central: Metropolitan Detroit, Iowa (2,320 patients); (4) West: Hawaii, New Mexico, Seattle (Puget Sound), Utah, San Francisco-Oakland SMSA, San Jose-Monterey, Los Angeles, Greater California (excluding SF, LA, and SJ), Alaska (12,753 patients). Results: Statistically significant differences in the rates of overall patient survival (P < 0.001) and the incidence of glioblastoma (24.31, 22.6, 20.35, 15.03 per 100,000/year in the South, Northeast, West, North Central regions, respectively) were identified between geographic regions. Multivariate Cox regression analysis demonstrated that overall survival was better in patients of Asian or Pacific Islander race. In addition, age, registry site, marital status, tumor laterality, histological classification, the extent of disease, tumor size, tumor extension, and treatment methods were identified as significant prognostic factors. Conclusion: Glioblastoma incidence is geographic region and race/ethnicity–dependent.

Irregularly structured brain tumors, such as glioblastomas, challenge attempts to visualize and quantify their three dimensional structure. Magnetic resonance imaging (MRI) represents one tool for attempting to noninvasively track tumor size. MR images demonstrate widely varying perceived tumor margins. In addition, adjunct therapies, such as the administration of steroids, greatly affect the volumes perceived in images formed by certain pulse sequences. In this study tumors were grown in 15 dogs and the tumor size tracked for a period of time. The dogs were placed on dexamethasone for a week and another series of scans was obtained. No other therapies were provided. The data for visualized tumor size are provided for T1, T2, and proton density. Weighted images are provided and the relationships between the scans are discussed.

A new method of in vivo quantitation of peritumoural brain oedema using NMR relaxation time imaging (T1-maps) and Gd-DTPA-enhanced Blood-Tumour-Barrier (BTB) analysis is presented. The method is based on image pixel histogram analysis and a fast imaging method combined with arterial [Gd-DTPA]-measurement. The method was applied in 26 brain tumour patients, studied prior to--and 1, 3 and 7 days after initiation of dexamethasone. Oedema resorption rate following dexamethasone treatment was almost equal in glioblastomas and metastases, mean T1 being reduced by ca. 12% in 7 days. In meningiomas no significant changes in peritumoural oedema could be detected. Simultaneous BTB-analysis was obtained in 4 patients showing correlation between oedema resorption in vivo and reduction of BTB transport rate constant Ki after 7 days of steroid treatment. This method is a powerful tool in quantitation and monitoring of brain oedema in vivo, as both steroid influence on oedema resorption and on BTB-defect can be monitored simultaneously.