Treatment Of Optic Nerve Gliomas Research Articles

Current treatment of optic nerve gliomas.

Optic pathway gliomas are low-grade neoplasms that affect the precortical visual pathway of children and adolescents. They can affect the optic nerve, optic chiasm, optic tracts and radiations and can either be sporadic or associated with neurofibromatosis type one. Gliomas isolated to the optic nerve (ONG) represent a subgroup of optic pathway gliomas, and their treatment remains controversial. New developments in ONG treatment have emerged in recent years, and it is necessary for clinicians to have a current understanding of available therapies. The current review of the literature covers the background of and recent developments in ONG treatment, with a focus on standard chemotherapy, new molecularly targeted therapies, radiation therapy and surgical resection and debulking. Although standard chemotherapy remains the mainstay of ONG treatment, newer molecularly targeted therapies such as mitogen-activated protein kinase kinase inhibitors and bevacizumab represent a promising new treatment modality, and clinical studies are ongoing.

Update in management of optic nerve glioma (part 2)

SummarySignificant controversy exists in the treatment of optic nerve glioma because of the absence of evidenced‐based trials demonstrating efficacy for various treatments administered over the years, from radiation therapy to various chemotherapeutic regimens and combinations thereof. Elements of tumor biology will be discussed along with fundamental properties of anti‐mitotic regimens administered to date, as well as newer agents proposed targeting protein synthesis rather than DNA replication. Discussion of how tumor suppressor gene status (NF1) should be taken into consideration when deciding upon a treatment modality will also be discussed. Novel vision sparing surgical modalities applicable to NF1‐associated orbital gliomas in particular will be reviewed.

Optic nerve glioma: an update.

Optic nerve glioma is the most common optic nerve tumour. However, it has an unpredictable natural history. The treatment of optic nerve gliomas has changed considerably over the past few years. Chemotherapy and radiation therapy can now stabilize and in some cases improve the vision of patients with optic nerve gliomas. The treatment of optic nerve glioma requires a multi-disciplinary approach where all treatment options may have to be implemented in a highly individualized manner. The aim of this review article is to present current diagnostic and treatment protocols for optic nerve glioma.

Radiation-Induced Neovascular Glaucoma: Dose and Volume Issues

Dear Editor: I read with great interest the article by Jeon et al., titled 'Neovascular glaucoma following stereotactic radiosurgery for an optic nerve glioma: a case report' [1]. Eight months after the patient underwent radiosurgery in the affected orbit, the intraglobular mass regressed to a partially residual retroglobular nodule; however, neovascular glaucoma (NVG) developed in the same eye. The authors stated that the stereotactic image-guided robotic radiosurgery using the Cyberknife system for the treatment of optic nerve glioma (ONG) might cause and should be selectively utilized. Although there seems to be a causal relationship between radiosurgery and the development of NVG, some issues need to be clarified. First, the authors suggested the post-radiation development of cataract in the affected eye supports their speculation that radiation effects may be the most likely causative factor of in their case. To demonstrate that a complication is radiation-induced, the radiation dose must be taken into account. The radiobiologic model of acute and late effects on normal human organs according to the radiation dose and volume has been well established through in vivo and in vitro studies, and it is true that radiotherapy can affect the retina, lens, conjunctiva, lacriminal apparatus, optic nerve, and eyelids. However, retinitis and optic neuropathy are found to occur following only high doses of radiation greater than 50 to 65 Gy, whereas cataracts are reported to develop following small radiation doses as low as 10 to 18 Gy, due to the differences in the sensitivities of the normal organs [2]. In the present case, the total irradiated dose of 16 Gy in four fractions was sufficiently high to cause lens opacity but was too low to have any effects on the retina or the optic nerve (16 Gy of four fractions equals 25 Gy with 2 Gy per fraction according to the biologically effective dose calculation, α/β=3). In the uveal melanoma cases, which the authors referred to as NVG after stereotactic radiosurgery for intraocular tumors, the target dose for the tumor apex was set at greater than 100 Gy. Moreover, plaque brachytherapy was used in those melanoma cases, instead of stereotactic radiosurgery [3]. Second, the volume irradiated is also an important factor in the development of NVG. Recently, Hirasawa et al. [4] found radiation damage to the anterior segment of the eye and the optic disk to be a risk factor for based on a dose-volume histogram analysis. In their study, both the dose to the anterior segment of the eye and the optic disc and the volume irradiated with greater than 50 Gy were statistically significant factors contributing to the development of NVG. Current advances in planning techniques for stereotactic radiosurgery aimed to minimize the dose to the anterior segment and the disc can reduce the risk of this complication. One of these new instruments, the CyberKnife robotic radiosurgery system (Accuray, Sunnyvale, CA, USA), used in this case, enables delivery of high radiation doses to the target with a much steeper dose gradient outside the tumor volume compared with those of other treatment systems that have been reported to produce [5]. Using the Cyberknife system, far less than 50% of the total dose generally affects the anterior segment of the eye. Dose and volume issues need to be carefully considered when determining the cause-and-effect relationships between radiation therapy and its associated complications.

Cranial-orbital approach in the treatment of optic nerve glioma

To summarize the experience in cranial-orbital approach in the treatment of optic nerve glioma. The clinical data of 35 patients with optic nerve glioma diagnosed by CT and MRI, 26 males and 9 females; aged 13 (1 - 54), with the main clinical presentations of visual defection and ex-ophthalmo and with the courses from 1 to 36 months, who underwent operation via the cranial-orbital approach 36 times, were analyzed. The diagnosis was confirmed by pathology after operation in 35 cases. Follow-up was conducted for 3 months to 8 years. Total resection was achieved in 29 cases, and subtotal resection in 6 cases. The surgical complications included temporary cerebrospinal fluid rhinorrhea (2 cases) and cataract (1 cases), and no ocular movement dysfunction was found. The follow-up rate was 77.1% (27/35). Three cases suffered from recurrence, spinal metastasis was found in 1 case, and 1 case died. resection of optic nerve glioma via cranial-orbital approach is effective. However, since residual tumor may remain in the optic nerve canal, post-operative radiation therapy is recommended.

Optic nerve gliomas. I. Clinical diagnosis and pathology.

At the National Institute of Neurosurgery a team of ophthalmologists and neurosurgeons has for 20 years been collaborating in the research and treatment of optic nerve gliomas. Among 34 patients, 30 were under the age of 20 years, and 20 under the age of 10 years. Of the 20 patients younger than 10 years, 16 were girls. The clinical symptoms were classified into three groups: I. Unilateral visual impairment with unilateral axial proptosis (16 patients), strabismus (6 cases), and typical X-ray findings of the skull. II. Uni- or bilateral visual impairment without proptosis (12 patients), depressed vision in the homolateral eye (9 patients), hemianopia (2 out of 4 examined patients) and hemiparesis (6 cases). III. Uni- or bilateral visual impairment without proptosis but with hormonal or metabolic disturbances (6 patients). Carotid angiography and PEG were performed in groups II and III and revealed a picture that is characteristic of suprasellar tumours. 99mTc pertechnetate scanning was done in six cases and showed isotope accumulation in the tumour in five. Pathologically, considering also the clinical aspects, two types of localization merit consideration: 1. The relationship between the tumour and the optic nerve (tumours growing within and extending beyond the optic pathways, respectively) and 2. The site of the tumour within the optic nerve (intraorbital, intraorbital and intracranial, intracranial only, chiasmal, and diffuse). Our data of histology and tissue culture prove the benign nature of the tumour even in the recurrences.