gms | German Medical Science

Intracranial visual pathway gliomas are in the majority pilocytic astrocytomas originating from the optic chiasm and optic tracts. Those originating from the optic tracts often mimic hypothalamic, mediotemporal, basal, or peduncular tumours. Exophytic or intrinsic local growth is erratic, it can be self-limiting, spontaneous regression has been observed, as well as rapid growth and malignant behaviour. The prognostic significance of NF1 remains unclear. Correspondingly therapeutic regimens range from aggressive surgery, radio- and chemotherapy to therapeutic nihilism. Any treatment is meaningless if not mirrored by improved functional outcome and either prolonged survival maintaining a good quality of life or long progression-free intervals after therapy. To optimize the benefit/risk ratio in these tumours we use stereotactic methods for diagnosis and treatment in patients who present with neurologic, endocrinologic or ophthalmologic symptoms. The histological diagnosis and grading is based on radiographic features and, in all patients, on stereotactic serial biopsy. Symptomatic but non-progressive tumours are followed conservatively. Interstitial radiosurgery with iodine-125 implants is used to treat progressive tumours resulting in 5- and 10-year survival rates above 85 and 81%, respectively. Our retrospective data show that in these circumscribed low-grade gliomas of the chiasm/ hypothalamus and of the optic tracts interstitial radiosurgery leads to long-term survival and reproducible reduction of tumour volume without significant morbidity and mortality. The current policy at our institution is to document tumour progression, to clarify the histology including immunohistochemistry and, in case of low grade gliomas, to treat with interstitial radiosurgery. Chemo- and radiotherapy are second line treatments and used only for patients older than five years with locally uncontrolled tumour progression.