Intramedullary metastasis in breast cancer--a comprehensive literature review

Background: Intramedullary breast cancer metastasis (IMBCM) is considered rare but its true incidence is unknown. Previous reviews of this subject are few and provided limited information.

Objective: To evaluate the precise location(s) of IMBCM, its concurrence rate with brain metastasis, its frequency compared to other cancers, intervals between breast cancer diagnosis and detection of IMBCM and between detection of IMBCM and death, frequency of various clinical symptoms, neuroimaging, cerebrospinal fluid (CSF) and biomarker data, treatment strategies and survival issues.

Study design: All relevant literature from 1900 to present was identified through Yale search Engine including but not limited to Medline/Pub Med, Ovid and Erasmus.

Results: A total of 36 publications were identified describing 85 patients with IMBCM. Breast cancer was the second highest source of intramedullary metastasis after lung (26.5% versus 45%). Cervical and thoracic cord was equally affected. Presence of thoracic cord lesions (P=0.039), concurrent brain metastasis, bladder dysfunction and Brown-Sequard syndrome were associated with a more unfavorable prognosis. Treatment strategies which included surgery suggested prolonged survival. Patients with breast metastasis to the spinal cord had longer survival than lung metastasis (P=0.05). The data on CSF and tumor markers was too limited to be conclusive.

Conclusions: Introduction of Magnetic Resonance Imaging has significantly increased the detection rate of IMBCM. Factors associated with better prognosis are presented. Definition of the true incidence of IMBCM would require a prospective clinical and neuroimaging study.