Evaluation of brain metastasis edema in breast cancer patients as a marker for Ki-67 and cell count—A single center analysis

Abstract

Background Peritumoral edema is an important cause of morbidity and mortality in patients with breast cancer brain metastases (BCBM). The relationship between vasogenic edema and proliferation indices or cell density in BCBM remains poorly understood. Purpose To assess the association between tumor volume and peritumoral edema volume and histopathological and immunohistochemical parameters in BCBM. Materials and Methods Patients with confirmed BCBM were retrospectively identified. The tumor volume and peritumoral edema volume of each brain metastasis (BM) were semi-automatically calculated in axial T2w and axial T2-fluid attenuated inversion recovery (FLAIR) sequences using the software MIM (Cleveland, Ohio, USA). Edema volume was correlated with histological parameters, including cell count and Ki-67. Sub-analyses were conducted for luminal B, Her2-positive, and tripe negative subgroups. Results Thirty-eight patients were included in the study. There were 24 patients with a single BM. Mean metastasis volume was 31.40 ± 32.52 mL and mean perifocal edema volume was 72.75 ± 58.85 mL. In the overall cohort, no correlation was found between tumor volume and Ki-67 (r = 0.046, p = .782) or cellularity (r = 0.028, p = .877). Correlation between edema volume and Ki-67 was r = 0.002 ( p = .989), correlation with cellularity was r = 0.137 ( p = .453). No relevant correlation was identified in any subgroup analysis. There was no relevant correlation between BM volume and edema volume. Conclusion In patients with breast cancer brain metastases, we did not find linear associations between edema volumes and immunohistochemical features reflecting proliferation potential. Furthermore, there was no relevant correlation between metastasis volume and edema volume.