Status: Article in preparation for submission.
Background: Cancers of unknown primary (CUP) are metastatic tumors of which the site of origin cannot be identified. Guidelines regarding care for CUP patients are limitedly available, particularly for those who present with (synchronous) single or multiple brain metastases (BM-CUP). Knowledge on the incidence, and survival is scarce, but is urgently needed to reveal current challenges and points for improvement in care for patients with BM-CUP.
Methods: We performed a literature search on CUP patients and BM in PubMed using the terms “CUP” OR “cancer of unknown primary” AND “brain metastases”, focusing on reports published between 2017 and 2021. Also, information from the Dutch National Cancer Registry (NCR) was collected to review current practices in The Netherlands. Variables considered were age, gender, presence and localization of brain metastases.