Osmotic blood-brain barrier disruption chemotherapy for diffuse pontine gliomas

The prognosis for patients with diffuse pontine gliomas (DPG) remains poor. New aggressive innovative treatments are necessary to treat this disease. From 1984 to 1998, eight patients (4M/4F), median age 11 years, with DPG were treated with monthly osmotic blood-brain barrier disruption (BBBD) chemotherapy using intraarterial carboplatin or methotrexate and intravenous cytoxan and etoposide. Patients presented for a median duration of 6 weeks with increased intracranial pressure, long tract signs, diplopia, ataxia, and nausea/vomiting. DPG was demonstrated on magnetic resonance (MR) imaging in seven patients and on CT in one. Two patients had biopsies that showed an astrocytoma and an anaplastic astrocytoma. Three tumors enhanced on MR imaging after contrast administration. Three patients had radiation therapy before BBBD chemotherapy and four afterwards. Two patients had chemotherapy (tamoxifen, topotecan) before BBBD chemotherapy and two afterwards. In general, patients were evaluated with MR imaging every 3 months to monitor for a response to treatment. The median number of chemotherapy cycles that were administered by BBBD was 10, mean 10. Three patients also received one, two, or three cycles of intraarterial chemotherapy without BBBD. One patient that was started on carboplatin was converted to methotrexate, and five that were started on the methotrexate protocol were later converted over to carboplatin. One patient received monthly methotrexate followed by 14 days of procarbazine and one patient started on methotrexate was switched to navelbine. MR imaging demonstrated two partial responses, five patients with stable disease, and one with disease progression. The median time to tumor progression was 15 months with the range from <1 to 40 months. The median survival from the time of diagnosis was 27 months, ranging from 7 to 80 months. The median survival time from the first BBBD or intraarterial treatment was 16.5 months, ranging from 5 to 69 months. One patient was lost to follow-up with an unknown date of death. Although the sample size is small, the TTP and survival times are longer than those previously reported in other DPG series. In addition, the ability to demonstrate stable disease or partial responses in DPG on MR imaging argues for the therapeutic benefit of BBBD chemotherapy. The enhanced delivery of chemotherapy afforded by osmotic BBBD supports the further examination of this treatment modality for patients with DPG.