Cancer-related movement disorders: A scoping review and diagnostic approach

Cancer-related movement disorders (CRMDs) comprise a diverse group of neurological complications of cancer. They result from varied etiologies and can be associated with compromised quality of life and poor prognosis. CRMDs can be divided into two broad categories: movement disorders resulting from cancer-related processes, such as direct tumor infiltration and paraneoplastic disease, and those that are a consequence of cancer-directed treatments, including classic therapies, such as chemotherapy and radiation therapy, novel treatments (eg immunotherapies and CAR T-Cell therapies), and various supportive treatments. A clear understanding of the breadth of CRMDs is vital, as effective management relies upon accurately identifying their underlying etiology. In this scoping review, we provide a comprehensive categorization of CRMDs based on their underlying etiology and phenomenology. Additionally, we propose a structured framework to guide the diagnostic evaluation and management of CRMDs, with the goal of facilitating timely diagnosis and, ultimately, improved patient outcomes.