Standard evaluations of NF-1 tumor and treatment response are inadequate and current therapies are ineffective. We conducted studies using MRI, MRS, and PET in 28 NF-1 patients with newly diagnosed brain tumors and 7 with progressive tumors. Preliminary results show MRS and PET profiles similar to non-NF1 tumors. Predictive factors have not been identified. However, thalamic hypometabolism and hypoperfusion is significant in these patients. Neuroimaging data requires re-analysis in 9 months after all scheduled studies are completed. To evaluate new treatments, we conducted trials of cis-retinoic acid, interferon, or VP16 in patients with optic pathway tumors (Stratum 1 n=13) and interferon or VP16 in plexiform neurofibromas (Stratum 2, n=57). On Stratum 1, one patient had a minor response, 5 had stable disease, 4 had tumor growth therapy, and one had tumor growth after therapy. On Stratum 2, 10 had clinical improvement and only 4/57 had neurofibroma growth after therapy. Treatment trial results suggest that optic pathway tumors are not likely to be more responsive to the selected study agents than to conventional therapy. However, CRA and IFN therapy may delay or prevent further growth of PN. If this finding is substantiated, it may have a major impact on NF-1 therapeutic options.
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