Tag: Stereotactic radiosurgery

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Tolerance of the Optic Apparatus in Single-Fraction Irradiation Using Stereotactic Radiosurgery: Evaluation in 100 Patients With Craniopharyngioma

Neurosurgery 66:688-695, 2010. DOI: 10.1227/01.NEU.0000367554.96981.26

OBJECTIVE: To determine the limiting dose to the optic apparatus in single-fraction irradiation in patients with craniopharyngioma treated with gamma knife radiosurgery (GKRS).

METHODS: One hundred patients with 109 craniopharyngiomas treated with GKRS were evaluated with a median follow-up period of 68 months. Tumor volume varied from 0.1 to 36.0 (median, 3.3) cm3. Marginal doses varied from 10 to 18 (median, 11.4) Gy. Maximum dose to any part of the optic apparatus varied from 2 to 18 (median, 10) Gy.

RESULTS: The actuarial 5- and 10-year overall rates of survival of tumor progression after GKRS were 93% and 88%, respectively. Similarly, the actuarial 5- and 10-year progressionfree survival rates were 62% and 52%, respectively. Among 94 patients in whom visual function was evaluable after GKRS, only 3 patients developed radiation-induced optic neuropathy, indicating an overall Kaplan-Meier radiation-induced optic neuropathy rate of 5%. Of these patients, 2 received 15 Gy or greater to the optic apparatus. Another patient who received 8 Gy or less had undergone previous fractionated radiation therapy with a biologically effective dose of 60 Gy.

CONCLUSION: The optic apparatus seems to be more tolerant of irradiation than previously thought. Careful dose planning is essential, particularly in patients who underwent prior external beam radiation therapy.

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Gamma knife radiosurgery for the treatment of glomus jugulare tumors

Journal of Neuro-Oncology. doi:10.1007/s11060-009-0002-6

The treatment of glomus jugulare tumors represents a challenge for the neurosurgeon, since they invade major vessels and compress critical cranial nerves, resulting in significant morbidity from tumor resection. Among alternative and complementary treatment options, gamma knife radiosurgery is a less invasive procedure and may provide better protection of vital structures. This study aimed to evaluate the efficacy and long-term outcomes of gamma knife surgery in the treatment of these tumors in a large series with the longest follow-up period compared with previous reports. A total of 18 patients with glomus jugulare tumors that underwent gamma knife radiosurgery (GKS) were included. Eleven patients had a history of previous microsurgical treatment. The mean marginal radiation dose was 15.6 Gy (median 15 Gy, range 13–20 Gy). Patients were followed for a mean period of 52.7 months (median 41.5 months); the effect of gamma knife radiosurgery was evaluated using magnetic resonance (MR) images. Based on the last MR images, tumor control could be achieved in 17 out of 18 patients (94.4%). No complications such as radiation-induced peritumoral edema or radiation necrosis occurred. Neurological follow-up examinations revealed improved clinical status in ten patients (55.6%), stable neurological status in seven (38.9%), and deterioration in one patient (5.5%). At the last visit, 17 out of 18 patients were alive. Our results indicate that stereotactic radiosurgery is an effective and safe treatment modality in the management of glomus jugulare tumors, particularly for residual or previously untreated small tumors.

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