Intradural Cauda Equina Metastases: A Systematic Review of Clinico-radiological Features, Management, and Treatment Outcomes

Background/Aim: Intradural cauda equina metastases (ICEM) are rare tumors that reduce functional status. Surgery and radiation are feasible and effective treatments but may have debilitating complications. We systematically reviewed the literature on ICEMs. Materials and Methods: PubMed, Scopus, Web of Science, and Cochrane were searched for studies reporting clinical data of patients with ICEMs. Clinical characteristics, management strategies, and treatment outcomes were analyzed. Results: We included 40 studies comprising 123 patients. Median age was 57 years. The most frequent primary tumors were lung (18.7%), breast (13%), and renal carcinomas (11.4%). Median time from primary tumor diagnosis to ICEMs' presentation was 36 months. The most common presenting symptoms were lower back pain (74%) and motor deficits (62.6%), with acute cauda equina syndrome documented in 36 patients (29.3%). Most lesions were diagnosed at magnetic resonance imaging (56.9%) or computed tomography myelography (32.5%). All cases were treated with decompressive laminectomy and tumor resection, with partial resection (82.1%) more often than complete (15.4%). Adjuvant radiotherapy (83.7%) and/or chemotherapy (10.6%) were often administered. Most patients experienced post-treatment symptom improvement (86.2%) and favorable radiological response (82.9%). ICEM recurrences were reported in 4 cases (8.5%) with median local tumor control of 7 months. At last follow-up, most patients were dead (62.9%) with median overall-survival of 10 months. Conclusion: Patients with ICEMs have poor prognoses and significant tumor burden. Surgery and locoregional radiotherapy may offer optimal clinical and radiological outcomes but have a limited role in improving local tumor control and overall survival.