40. Leptomeningeal metastasis: When discontinue treatment?

Treatment of meningeal metastasis is based on intrathecal (i.t.) administration of MTX and Ara-C. In most patients survival time is too short to verify the real benefit of therapy. In long survivors a general agreement does not exist on how long to treat the disease. We report a case of a 53-years-old woman with breast cancer and bone metastasis. 10 months ago she complained mild cephalgia and depression. A MR scan showed leptomeningeal metastasis confirmed by CSF examination. She was successfully treated with MTX, 10 mg/m ² weekly i.t. via lumbar puncture until the results of CSF cytodiagnosis became negative (5 doses). After 8 weeks of improvement she complained dizziness. CSF examination showed elevated protein concentration and malignant cells. A new course of MTX i.t. was administered. After 8 doses CSF was always mild positive. To improve therapeutic effects we decided to install an Ommaya device. After 3 doses of MTX (10 mg/m ² weekly intraventricular) CSF findings returned to normal but a new MR scan revealed a mild leukoencephalopathy. Treatment was interrupted to avoid severe neurotoxicity. After 4 weeks a new dose was administered. CSF was normal for proteins, glucose and cells but with high levels of CEA. Patient is alive and asymptomatic. This unusual case of "remittent" leptomeningeal metastasis demonstrates that in long survivors, intrathecal therapy should be continued perhaps indefinitely.