Correlation of large brain edema with favorable prognosis in patients with single brain metastases.

Abstract

2053 Background: The sub-cohort of brain metastases (BM) patients (pts) with single BM has relatively favorable survival times, but novel prognostic factors are needed to individualize patient management. Methods: We retrospectively evaluated pre-operative magnetic resonance images in patients, who underwent neurosurgical resection of a single BM. The localization and largest diameter of the BM was recorded. The extent of brain edema (BE) was graded on contrast-enhanced T1, T2 and fluid-attenuated inversion recovery (FLAIR) images as follows: BE <1cm, BE >1 cm without affection of the contralateral hemisphere, BE >1cm with affection of the contralateral hemisphere. Further, immunohistochemically assessed expression of hypoxia-induced factor 1 alpha (HIF1a) was analyzed in each BM tissue specimen. Results: 159 pts were studied (81 male, 78 female; age range 24 to 80 years, median 58). The primary tumors were lung carcinoma in 74, breast cancer in 26, kidney cancer in 13, colorectal cancer in 11, melanoma in 9 and other tumor types in 26 cases. At univariate analysis, we found a significant positive correlation of overall survival time (OS) with young age, Karnofsky index >80, non-melanoma histology, and, surprisingly, large BE (p<0.05, log-rank test). At multivariate analysis, pts age, histological diagnosis and extent of BE remained independent prognostic parameters (Cox regression model, p<0.05). We found a significant positive correlation of extent of BE with expression of HIF1a (Mann-Whitney-U test, p=0.003). Conclusions: Large BE positively and independently correlates with favorable prognosis in pts operated for single BM. Peritumoral BE correlates with HIF1a expression, indicating a possible role of tumor hypoxia in its formation. [Table: see text]