The Brain Pre-Metastatic Niche: Biological and Technical Advancements.

Metastasis, particularly brain metastasis, continues to puzzle researchers to this day, and exploring its molecular basis promises to break ground in developing new strategies for combatting this deadly cancer. In recent years, the research focus has shifted toward the earliest steps in the formation of metastasis. In this regard, significant progress has been achieved in understanding how the primary tumor affects distant organ sites before the arrival of tumor cells. The term pre-metastatic niche was introduced for this concept and encompasses all influences on sites of future metastases, ranging from immunological modulation and ECM remodeling to the softening of the blood-brain barrier. The mechanisms governing the spread of metastasis to the brain remain elusive. However, we begin to understand these processes by looking at the earliest steps in the formation of metastasis. This review aims to present recent findings on the brain pre-metastatic niche and to discuss existing and emerging methods to further explore the field. We begin by giving an overview of the pre-metastatic and metastatic niches in general before focusing on their manifestations in the brain. To conclude, we reflect on the methods usually employed in this field of research and discuss novel approaches in imaging and sequencing.

Outcome and characteristics of patients with adult grade 4 diffuse gliomas changing sites of treatment.

PURPOSE: With increasing patient self-empowerment and participation in decision making, we hypothesized that patients with adult-type diffuse gliomas, CNS WHO grade 4 who change sites of treatment differ from patients being entirely treated in one neuro-oncological center. METHODS: Prospectively collected data from all diffuse glioma grade 4 patients who underwent treatment in our neuro-oncological center between 2012 and 2018 were retrospectively examined for differences between patients having initially been diagnosed and/or treated elsewhere (External Group) and patients having entirely been treated in our neuro-oncological center (Internal Group). Additionally, a matched-pair analysis was performed to adjust for possible confounders. RESULTS: A total of 616 patients was analyzed. Patients from the External Group (n = 78) were significantly younger, more frequently suffered from IDH-mutant astrocytoma grade 4, had a greater extent of tumor resection, more frequently underwent adjuvant therapy and experienced longer overall survival (all p < 0.001). However, after matching these patients to patients of the Internal Group considering IDH mutations, extent of resection, adjuvant therapy, age and gender, no difference in patients' overall survival was observed anymore. CONCLUSION: The present study demonstrates that mobile diffuse glioma grade 4 patients stand out from a comprehensive diffuse glioma grade 4 patient cohort due to their favorable prognostic characteristics. However, changing treatment sites did not result in survival benefit over similar patients being entirely taken care of within one neuro-oncological institution. These results underline the importance of treatment and molecular markers in glioma disease for patients' self-empowerment, including changing treatment sites according to patients' needs and wishes.