Abstract 738: Re-irradiation for recurrent malignant glioma by boron neutron capture therapy

Abstract

Abstract OBJECTIVE: Boron neutron capture therapy (BNCT) is based upon the nuclear reaction that occur when non-radioactive boron-10 (10B) is irradiated with low energy neutrons to produce high energy a particles (10B[n, alpha] 7Li). In order for BNCT to be successful, a sufficient amount of 10B and neutrons must be delivered to the tumor. We have applied tumor selective particle radiation known as boron neutron capture therapy (BNCT) to malignant brain tumors. As there has been no standard treatment for recurrent gliomas so far, it has been difficult to evaluate the results of BNCT for recurrent malignant gliomas. Here we introduce the survival benefit of BNCT for recurrent malignant glioma patients, with special reference to new RPA classification recurrent malignant gliomas advocated by New Approaches to Brain Tumor Therapy CNS Consortium (NABTT, JCO 2007). METHODS: Since 2002, we have treated 27 cases of recurrent malignant gliomas with BNCT. All cases had been treated by standard treatment including radiotherapy mainly by XRT prior to BNCT. After BNCT, patients were followed by MRI and F-BPA (amino acid)-PET. Cause of death was estimated by these modalities. Also overall survival was evaluated with special reference to RPA classes advocated by NABTT as above. RESULTS: All cases showed radiographical improvement at once. The median survival time (MST) of BNCT-treated recurrent gliomas was 10 months, while that of total NABTT cases (N=333) was 7 months. MST of NABTT RPA classes were 25.7, 17.2, 3.8, 10.4, 5.6, 6.4 and 4.9 months for classes 1 to 7, respectively. The MST of BNCT-treated cases were 33, 24, 10, 9, 9, 12 and 11, for classes 1 to 7, respectively. BNCT showed good survival benefit especially for the most poor prognostic group (RPA class 3+7) from 4.4 months (NABTT) to 9.6 months. Conclusion: BNCT could prolong the survival of patients with recurrent gliomas not only for the good prognosis group but also for the poor prognosis group. Some of the prognostic factors of malignant glioma, such as KPS, tumor location, extent of surgery, are not independent factor each other. BNCT seems to have the survival benefits for such situations due to its tumor cell selectivity. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 738. doi:1538-7445.AM2012-738