Movement Disorders Associated With Breast Cancer: A Systematic Review

Background and Objectives: Movement disorders associated with breast cancer represent heterogeneous paraneoplastic and treatment-related neurological entities. This systematic review aimed to characterize clinical phenotypes, temporal relationships, immunological profiles, treatment strategies, and neurological outcomes of breast cancer–associated movement disorders. Methods: A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. PubMed, Embase, Scopus, and Google Scholar were searched. Case reports, case series, and cohort studies describing cerebellar syndromes and movement disorders associated with breast cancer in female patients were included. Data were synthesized descriptively. Results: A total of 172 published cases were identified. Cerebellar syndromes accounted for 82/172 cases (47.7%), with neurological symptoms preceding cancer diagnosis in 63/82 patients (76.8%). Pancerebellar degeneration was the most frequent phenotype (37/82, 45.1%), and anti-Yo antibodies predominated (49/82, 59.8%). Neurological outcomes were poor, with stabilization or deterioration in 50/82 patients (60.9%) and death in 22/82 (26.8%). Stiff-person syndrome comprised 34/172 cases (19.8%), frequently associated with anti-amphiphysin antibodies (23/34, 67.6%), and demonstrated better outcomes, with marked improvement in 20/34 patients (58.8%). Parkinsonism and other movement disorders accounted for 38/172 cases (22.1%) and showed heterogeneous immune-mediated and treatment-related mechanisms. Opsoclonus–myoclonus syndrome was identified in 18/172 cases (10.5%), most often paraneoplastic (15/18, 83.3%). Seventeen cohort studies, including 275 patients, confirmed cerebellar ataxia as the predominant phenotype (188/275, 68.4%), with deterioration or death in 99/275 patients (36.0%). Conclusions: Breast cancer–associated movement disorders are predominantly immune-mediated, frequently precede cancer diagnosis, and demonstrate phenotype-specific antibody associations and prognostic patterns, underscoring the importance of early recognition and targeted evaluation.