BMScope: A scoping review to chart the evolving clinical study landscape in brain and leptomeningeal metastasis

Recent studies have challenged the notion that patients with brain metastasis (BM) or leptomeningeal metastasis (LM) should be excluded from systemic therapy clinical trials. This scoping study summarizes the BM/LM clinical studies published between 2010 and 2023.

MEDLINE, CINAHL, CAB Abstracts, PsycINFO, Cochrane Library, HINARI, International Pharmaceutical Abstracts, PubMed, Scopus, Web of Science, and EMBASE electronic databases were searched on June 21, 2021. An updated search was performed on February 21, 2023. Eligible studies investigated a therapeutic intervention in solid tumor patients with BM and/or LM and reported a patient outcome. Extracted study-level data, including study type, publication date, geographical location, number of BM/LM patients in the study, primary tumor type, and type of therapeutic intervention, were collected.

4921 unique studies were eligible for analysis. The key finding is that BM/LM clinical research is expanding globally, both in observational studies and clinical trials. Despite the shift over time toward a higher proportion of systemic therapy trials, the majority still do not include patients with symptomatic disease and lack reporting of BM/LM-specific endpoints. Globally, there has been a trend to more international collaboration in BM/LM clinical studies.

Our analysis of the BM/LM literature charts the evolving landscape of studies involving this previously excluded population. Given the increasing clinical research activity, particularly involving late-stage systemic therapy trials, it is imperative that due consideration is given to the intracranial activity of new investigational agents. Wider adoption of standardized reporting of intracranial-specific endpoints will facilitate the evaluation of relative intracranial efficacy.