Around 5 percent of all patients with metastatic breast cancer go on to develop distant metastases in the meninges, also known as meningeal carcinomatosis. The median survival of these patients is between 3.5 and 4.5 months. Current treatment approaches are based on radiotherapy, systemic and intrathecal therapy. Methotrexate, liposomal cytarabine and trastuzumab are the most common substances used for intrathecal therapy. The aim of this review was to provide an overview of these intrathecal therapy options for meningeal carcinomatosis. A systematic search of the literature was carried out in PubMed using the following search terms: "meningeal metastases", "meningeal carcinomatosis", "leptomeningeal metastasis", "leptomeningeal carcinomatosis", "leptomeningeal disease", "breast cancer", "MTX", "methotrexate", "DepoCyte", "liposomal cytarabine", "trastuzumab" and "anti-HER2". This search resulted in 75 potentially relevant studies, 11 of which were included in this review after meeting the previously determined inclusion and exclusion criteria. The studies differ considerably with regards to study design, cohort size, and dosages of administered drugs. In principle, intrathecal therapy has a tolerable side-effects profile and offers promising results in terms of the median overall survival following treatment with trastuzumab for HER2-positive primary tumors. The focus when treating meningeal carcinomatosis must be on providing a multimodal individual therapeutic approach. However, comprehensive studies which compare the efficacy and side effects of individual pharmaceuticals are lacking. Because of the poor prognosis associated with meningeal carcinomatosis, an approach which treats only the symptoms (best supportive care) should always be considered and discussed with affected patients.
Keywords: cytarabine; intrathecal therapy; meningeal carcinomatosis; methotrexate; trastuzumab.
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