Multisession Gamma Knife Radiosurgery Research Articles

Safety and efficacy of multisession gamma knife radiosurgery for residual or recurrent pituitary adenomas.

To define the efficacy and complications of multisession Gamma Knife radiosurgery (MGKRS) delivered in three consecutive sessions for the treatment of residual or recurrent pituitary adenomas (PAs). This was a retrospective study of data from the Neurosurgery and Gamma Knife Radiosurgery Department at San Raffaele Hospital between May 2008 and September 2017. We recruited 47 consecutive patients undergoing MGKRS in three consecutive fractions for residual or recurrent PA with a distance from the anterior optic pathway inferior to 2-3 mm. Thirty-eight (80.8%) patients had a nonfunctioning-PA (NFPA) while 9 (19.2%) had a hormone-secreting PA (HSPA). Tumor control was achieved in 100% of patients. Tumor shrinkage was seen in 33 out of 44 (75.0%) patients with a radiological follow-up. Mean tumor volume before MGKRS was 3.93 cm3. The mean tumor volume at last follow-up was 2.11 cm3, with a mean tumor shrinkage of 50.2%, as compared with baseline. One case of suspected radiation-induced optic neuropathy (RION) was documented while new-onset hypopituitarism for any axis occurred in 12 of the 31 (38.7%) patients at risk. The mean follow-up was 44.6 ± 4.0 months (range, 6-111 months). MGKRS is a valid alternative to external fractionated radiotherapy and other types of stereotactic radiosurgery for the treatment of PAs, achieving a high tumor control rate with a low risk of visual deterioration. Moreover, the majority of patients showed a significant reduction of tumor size in the long term.

Orbital apex venous cavernous malformation with optic neuropathy: treatment with multisession gamma knife radiosurgery

PurposeTo evaluate the efficacy and safety of multisession gamma knife radiosurgery (GKRS) for orbital apex venous cavernous malformation causing optic neuropathy.MethodsRetrospective cohort study in a single tertiary institution from January...

Hearing outcomes between multi-session and single-session radiosurgery for vestibular schwannoma: a single center study

Background: Hearing preservation rate after Gamma Knife radiosurgery (GKRS) for vestibular schwannoma (VS) remains low. The aim of this study was to study hearing outcomes between multisession and single session GKRS in patients with VS and determine prognostic factors associated with hearing preservation. Methods: A retrospective analysis of 561 consecutive patients with VS subjected to multisession (74 patients) or single session (487 patients) GKRS (from June 2011 to April 2015) was performed. Propensity score matching (PSM) based on patient age, gender, tumor volume and pre-GKRS hearing was used to compare the two groups. The tumor control rate and complications were evaluated, especially hearing preservation and its prognostic factors. Results: According to PSM, 29 patients from each group with similar characteristics were selected for the study. Patients’ age, tumor volume, pre-GKRS pure tone average (PTA) and radiographic follow-up period were not significantly different between the two groups (P>0.05). The tumor control rate was 75.9% for the multisession group compared with 62.1% for the single session group (P=0.1142); 20 patients had a less than 20 dB change in PTA in multisession group, with the hearing preservation rate of 69.0% (20/29) compared with 65.5% (19/29) in single session group (P=0.08). Multivariate analysis revealed that linear internal auditory canal (IAC) length was the only significant predictor of hearing loss in the multisession group. At last follow-up, one patient complaining of sudden hearing loss was diagnosed with tumor bleeding 12 months after multisession GKRS. One patient from multisession group and two patients from single session group suffered from temporal facial numbness. Facial spasm developed in one patient after multisession GKRS. Conclusions: Our results supported that multisession GKRS could be an effective and safe treatment option for VS compared to single session GKRS. The hearing preservation rate after multisession GKRS was not superior to single session radiosurgery in our short-term follow-up study. However, patients with longer IAC length may benefit from multisession strategy in terms of hearing preservation.

Single fraction and multisession Gamma Knife radiosurgery for craniopharyngioma.

The optimal management of residual or recurring craniopharyngioma is still a matter of debate even though adjuvant radiation therapy plays a crucial role. Aim of our study is to report the results of single fraction or multisession Gamma Knife radiosurgery (GKRS) in patients with craniopharyngioma. We included 50 consecutive patients treated from 1994 to 2016. All patients had at least one post GKRS magnetic resonance imaging reviewed at our center. Vital status of all patients was assessed at the end of 2016. There were 29 males (58.0%) and 21 females (42.0%). Mean age was 41.5 ± 2.8year. Single session GKRS was delivered in 29 patients (58.0%). The mean tumor volume was 2.15 ± 0.3cm3 and the mean prescription dose to the tumor margin was 14.3 ± 0.3Gy. During a mean follow-up of 74.6 ± 8.4months, seven patients (14.0%) had recurrence of disease. The 5- and 10-year recurrence-free survivals were 90.3% (95% CI, 81.0-99.6%) and 78.4% (95% CI, 59.9-96.9%), respectively. Multisession GKRS was not less effective than single fraction GKRS. Eighteen of the 28 patients (64.3%) had a tumor volume decrease of at least 10%. No serious side effects occurred after GKRS treatment, except for one case of mild visual worsening. GKRS was effective for controlling the growth of residual or recurrent craniopharyngioma. Serious side effects were uncommon. Multisession GKRS seems a very promising tool to allow performing GKRS even in patients with large residual or recurrent craniopharyngioma.

Multisession Gamma Knife Radiosurgery for Orbital Apex Tumors

This study was performed to analyze the outcome of multisession gamma knife radiosurgery (GKS) in benign tumors located at the orbital apex. Medical records of 23 patients who underwent multisession GKS for benign orbital apex tumors were reviewed retrospectively. Three patients were diagnosed by histology, and the other 20 patients were given the diagnoses on the basis of clinical and radiological findings. Diagnoses included cavernous hemangioma (8 cases), meningioma (8 cases), and schwannoma (7 cases). All patients were treated with 4 sessions of GKS with 12 hours of interval. Median marginal dose in each session was 5 Gy (range, 4.5-5.5 Gy) at the 50% isodose line (range, 50%-55%). Mean clinical and imaging follow-up duration after treatment were 52.1 and 34.2 months, respectively. Tumor control was achieved in 22 patients (95.7%). Significant tumor shrinkage was observed in 17 patients (73.9%), and mean tumor volume reduction rate was 53.9%. Visual function was improved in 16 patients (69.6%) and stable in 4 patients (17.4%). Deterioration of visual acuity was reported by 3 patients (13.0%). Clinical and radiological response to multisession GKS was most excellent in cavernous hemangiomas with tumor control in all patients, and the mean tumor volume reduction rate was 68.3%. Multisession GKS proved to be an effective and safe management strategy for benign orbital apex tumors. Response to treatment was different according to the pathology, and multisession GKS may be considered as the initial treatment of choice for specific pathology such as cavernous hemangioma.

Giving it your best shot.

In May 2014, the Leksell Gamma Knife Society held its 17th meeting in New York City (Fig. 1). The theme of the meeting was “Giving It Your Best Shot.” The theme resonates well with those practicing in the field of Gamma Knife radiosurgery. In fact, neurosurgeons and radiation oncologists performing Gamma Knife radiosurgery are frequently faced with challenging situations, and they must perform as well as possible despite uncertainty and occasionally long odds for success. The Gamma Knife has stood the test of time for more than 4 decades. For hundreds of thousands of patients, the Gamma Knife has delivered success far more often than failure. New York is one of the most vibrant and diverse cities in the world. The breadth of the scientific proceedings, liveliness of the discourse, and the diversity of participants hailing from more than 40 countries mirrored the ethos of the host city. Scientific proceedings covered such topics as neuro-immunology, fractionation, ethics, and epilepsy. In a sign that an old approach can become new again, Gamma Knife–effectuated ablation and behavioral radiosurgery were also topics covered in the plenary session. Fractionation not just with the Gamma Knife Extend but also with the Perfexion Plus will bring further innovation to the field. Multisession Gamma Knife radiosurgery is also likely to prove paradigm shifting. In a forward-thinking fashion, the meeting covered the topic of creating a Gamma Knife registry. Such a registry could allow for far-reaching, multicenter scientific studies. It could also help to advance the field in a more rapid fashion than any single individual center could do by itself. After all, the scientific literature related to Gamma Knife radiosurgery is mature and comprehensive. The remaining questions are more difficult to answer, and such questions frequently require greater amounts of high-quality data to answer. A Gamma Knife registry should provide the platform for acquiring and analyzing requisite data. Also, the registry could help to identify areas for practice improvement as a clinician compares his/ her results to peers. Finally, the registry may demonstrate areas for improved efficiency, quality, safety, and costeffectiveness in Gamma Knife radiosurgery. The articles contained in this supplement represent some of the more notable scientific work at the meeting. I would like to thank the following reviewers for their assistance: Drs. Veronica Chiang, Arnold Etame, Hideyuki Kano, Anthony Kaufmann, Jonathan Knisely, Douglas Kond ziolka, James Larner, Cheng-Chia Lee, L. Dade Lunsford, Ajay Niranjan, Gail Rosseau, Arjun Sahgal, David Schlesinger, John Suh, Zhiyuan Xu, and Chun-Po Yen. The Gamma Knife meeting in New York proved successful by any metric. The Gamma Knife remains an important neurosurgical tool, and the field appears as alive as the city of New York itself. (http://thejns.org/doi/abs/10.3171/2014.6.GKS141282)

Multisession Gamma Knife Radiosurgery: A Preliminary Experience with a Noninvasive, Relocatable Frame

To evaluate preliminary outcomes for a cohort of patients who were treated with multisession Gamma Knife radiosurgery (GKRS) using the new noninvasive vacuum-assisted immobilization system. A retrospective review was performed of 15 consecutive cases treated with multisession GKRS. Radiosurgical targets included 12 meningiomas, 1 nonfunctioning pituitary adenoma, 1 growth hormone-secreting pituitary adenoma, and 1 pilocytic astrocytoma. GKRS was delivered in 3-5 sessions to a mean tumor volume of 8.55 mL (median, 7.3 mL; range, 1.24-22.7 mL) with a mean margin dose of 19.7 Gy (median, 20 Gy; range, 15-25 Gy). The optic nerves, chiasm, and tracts received mean doses of 3.5 Gy (range, 0.7-5.7 Gy), 3.1 Gy (range, 1-4.4 Gy), and 2.6 Gy (range, 0.83-5.45 Gy) per session. Mean biologic equivalent dose (α/β = 2.5) was 60.9 Gy (median, 60 Gy; range, 45-79.8 Gy). Follow-up examinations were performed at 3- to 6-month intervals. Mean follow-up was 17.7 months (median, 13.8 months; range, 4-44.3 months), and tumor control was noted in all patients, with regression in 5 patients and stability in 10 patients. New neurologic deficits developed in 3 patients after treatment, but none of these deficits were permanent. Resection was performed in 1 patient with expressive aphasia with worsening of peritumoral T2 signal but a stable tumor on follow-up magnetic resonance imaging. The other 2 patients were managed conservatively for minor complications (ptosis, taste dysfunction), and their symptoms resolved. No patients developed deterioration in vision during the follow-up period. Preliminary experience with multisession GKRS appears promising, with reasonable tumor control and complication rates. Multisession stereotactic radiosurgery may expand the treatment envelope for intracranial pathologies, including targets with larger volumes and locations in close proximity to radiosensitive structures.

Whole-procedural Radiological Accuracy for Delivering Multi-session Gamma Knife Radiosurgery With a Relocatable Frame System

A newly developed Gamma Knife relocatable eXtend frame system has enabled the delivery of multi-session Gamma Knife radiosurgery without the use of skull pin fixation frame system. In this study, we investigate and report for the first time the whole procedural radiological accuracy for administering such treatments. To quantify the radiological alignment, the commonly used Winston-Lutz test was modified and used to determine the device accuracy of the eXtend frame system. Patient setup uncertainties relative to the device were further measured for a series of treatment sessions (n = 58), and then incorporated with the Winston-Lutz test results from individual patient-specific eXtend frame systems. The whole-procedure mean 3D radiological setup uncertainty was determined to be 0.69 ± 0.73 mm (1σ) from all the cases analyzed, and the mean 90% confidence level margins were found to be 0.55, 0.78 and 0.72 mm along the x-, y-, and z-axis, respectively. Our results therefore demonstrated that sub-millimetric radiological accuracy is clinically achievable for multi-session Gamma Knife radiosurgery treatments and a 1 mm margin along the major axes is sufficient for planning multi-session Gamma Knife radiosurgery treatments.

Benign Orbital Apex Tumors Treated with Multisession Gamma Knife Radiosurgery

The orbital apex is an important anatomic landmark that hosts numerous critical neurovascular structures. Tumor resection performed at this complex region poses a therapeutic challenge to orbital surgeons and often is associated with significant visual morbidity. This article reports the efficacy and safety of multisession gamma knife radiosurgery (GKRS) in benign, well-circumscribed tumors located at the orbital apex. Retrospective interventional case series. Five patients with visual disturbances resulting from a benign, well-circumscribed orbital apex tumor (3 cases of cavernous hemangioma and 2 cases of schwannoma). Each patient treated with GKRS with a total radiation dose of 20 Gy in 4 sessions (5 Gy in each session with an isodose line of 50%) delivered to the tumor margin. Best-corrected visual acuity, visual field changes, orbital imaging, tumor growth control, and side effects of radiation. All patients demonstrated improvement in visual acuity, pupillary responses, color vision, and visual field. Tumor shrinkage was observed in all patients and remained stable until the last follow-up. No adverse events were noted during or after the radiosurgery. None of the patients experienced any radiation-related ocular morbidity. From this experience, multisession GKRS seems to be an effective management strategy to treat solitary, benign, well-circumscribed orbital apex tumors.

Preliminary Report of Multisession Gamma Knife Radiosurgery for Benign Perioptic Lesions: Visual Outcome in 22 Patients

Radiosurgery may be contraindicated for lesions adjacent to the optic pathways because of the substantial risk of visual complication. Multisession radiosurgery has been tried as a compromise between single session radiosurgery and fractionated radiotherapy. The purpose of this study is to evaluate the outcomes of multisession gamma knife radiosurgery (GKRS) in 22 patients with perioptic lesions of benign pathology. In all 22 cases, the lesions were within 1 mm of the optic apparatus and were therefore not considered suitable for single session radiosurgery. Radiation was delivered in 3 to 4 fractions with a median cumulated marginal dose of 20 Gy (range, 15-20 Gy). During a mean follow-up of 29 months (range, 14-44 months), tumor control was achieved in 21 patients. Visual function improved in 7 patients, remained unchanged in 14 patients, and deteriorated in 1 patient with tumor progression. No other complication was observed. This preliminary result supports the idea that multisession GKRS may be an effective and safe alternative for treatment in perioptic lesions that are unsuitable for single session radiosurgery.