Continuous intrathecal treatment with methotrexate via subcutaneous port: implication for leptomeningeal dissemination of malignant tumors

Use of intrathecal (IT) chemotherapy combined with radiotherapy can extend survival of patients with untreated leptomeningeal dissemination of malignant tumors from one month to two to six months. The goal of the present study was to determine the effect of continuous IT (CIT) via a subcutaneous port that was placed using a neuronavigation system. Twenty patients with leptomeningeal dissemination (primary disease: 10 cancers, 6 gliomas and 4 lymphomas) were given 2–7 cycles of continuous IT (CIT) with methotrexate (MTX; 10 mg) administered into the lateral ventricle for 5 consecutive days biweekly. The concentration of MTX in the lateral ventricle was 7 to 10 × 10⁻⁶ M from Day 1 to 4. Response to this therapy included 6 patients with complete remission, 7 with progressive disease, and 7 with stable disease. Kaplan-Meier analysis revealed a median overall survival of 8 months while the overall survival rate for leptomeningeal specific death or for metastasis from cancer was 13 or 5 months, respectively. Complications of CIT with MTX were relatively low (<0.5%), and nausea and vomiting did not occur in any of the patients. In conclusion, CIT with 10 mg MTX via subcutaneous port for 5 days may improve the therapeutic effect and reduce the complications associated with treatment of leptomeningeal dissemination from malignant tumors. This would be a safe technique with possible implications that bear repeating more patients.