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

Background: 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 summarises the BM/LM clinical studies published between 2010 and 2023.

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

Results: 4921 unique studies were eligible for analysis. The key finding is that BM/LM clinical research is expanding globally, both observational studies and clinical trials. Despite the shift over time towards 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.

Conclusions: This 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 standardised reporting of intracranial-specific endpoints will facilitate evaluation of relative intracranial efficacy.