STEREOTACTIC RADIOSURGERY AND FRACTIONATED STEREOTACTIC RADIOTHERAPY FOR THE TREATMENT OF NONACOUSTIC CRANIAL NERVE SCHWANNOMAS

Neurosurgery ◽  
2008 ◽  
Vol 63 (4) ◽  
pp. 734-740 ◽  
Author(s):  
Timothy N. Showalter ◽  
Maria Werner-Wasik ◽  
Walter J. Curran ◽  
David P. Friedman ◽  
Xia Xu ◽  
...  

ABSTRACT OBJECTIVE To review outcomes after fractionated stereotactic radiotherapy (FSR) and stereotactic radiosurgery (SRS) for nonacoustic cranial nerve schwannomas. METHODS We reviewed medical records of 39 patients who received FSR or SRS for nonacoustic cranial nerve schwannomas at our institution during the period from 1996 to 2007. RESULTS Tumors involved Cranial Nerves V (n = 19), III (n = 2), VI (n = 3), VII (n = 5), IX (n = 2), X (n = 5), and XII (n = 2) and the cavernous sinus (n = 1). Irradiation was performed after partial resection, biopsy, or no previous surgery in 16, 2, and 21 patients, respectively. Twenty-four patients received FSR, delivered in 1.8- to 2.0-Gy fractions to a median dose of 50.4 Gy (range, 45.0–54.0 Gy). Fifteen patients received SRS to a median dose of 12.0 Gy (range, 12–15 Gy). Mild acute toxicity occurred in 23% of the patients. The 2-year actuarial tumor control rate after FSR and SRS was 95%. The median follow-up period was 24 months. Changes in cranial nerve deficits after stereotactic irradiation were analyzed for patients with follow-up periods greater than 12 months (n = 26); cranial nerve deficits improved in 50%, were stable in 46%, and worsened in 4% of the patients. No significant difference was observed for FSR compared with SRS with regard to local control or to improvement of cranial nerve-related symptoms (P = 0.17). CONCLUSION SRS and FSR are both well-tolerated treatments for nonacoustic cranial nerve schwannomas, providing excellent tumor control and a high likelihood of symptomatic improvement.


Neurosurgery ◽  
2011 ◽  
Vol 68 (5) ◽  
pp. 1200-1208 ◽  
Author(s):  
Clara Y. H. Choi ◽  
Scott G. Soltys ◽  
Iris C. Gibbs ◽  
Griffith R. Harsh ◽  
Gordon T. Sakamoto ◽  
...  

Abstract BACKGROUND: Surgical resection of nonvestibular cranial schwannomas carries a considerable risk of postoperative complications. Stereotactic radiosurgery (SRS) offers a non-invasive treatment alternative. The efficacy and safety of multi-session SRS of nonvestibular cranial schwannomas has not been well studied. OBJECTIVE: To analyze the results of single- and multi-session SRS of nonvestibular cranial schwannomas. METHODS: From 2001 to 2007, 42 lesions in 40 patients were treated with SRS at Stanford University Medical Center, targeting schwannomas of cranial nerves IV (n = 1), V (n = 18), VII (n = 6), X (n = 5), XII (n = 2), jugular foramen (n = 8), and cavernous sinus (n = 2). SRS was delivered to a median marginal dose of 18 Gy (range, 15-33 Gy) in 1 to 3 sessions, targeting a median tumor volume of 3.2 cm3 (range, 0.1-23.7 cm3). The median doses for treatments in 1 (n = 18), 2 (n = 9), and 3 (n = 15) sessions were 17.5, 20, and 18 Gy, respectively. RESULTS: With a median follow-up of 29 months (range, 6-84 months), tumor control was achieved in 41 of the 42 lesions. Eighteen of 42 lesions (43%) decreased in size; 23 tumors (55%) remained stable. There were 2 cases of new or worsening cranial nerve deficits in patients treated in single session; no patient treated with multi-session SRS experienced any cranial nerve toxicity (P = 0.18). CONCLUSION: SRS of nonvestibular cranial schwannomas provides excellent tumor control with minimal risk of complications. There was a trend towards decreased complications with multi-session SRS.



Neurosurgery ◽  
2008 ◽  
Vol 62 (suppl_5) ◽  
pp. A19-A28 ◽  
Author(s):  
Michael R. Girvigian ◽  
Joseph C.T. Chen ◽  
Javad Rahimian ◽  
Michael J. Miller ◽  
Michael Tome

ABSTRACT OBJECTIVE Patients with convexity and parasagittal (CPS) meningiomas treated with stereotactic radiosurgery (SRS) have been shown to be at risk for posttreatment symptomatic peritumoral edema (SPTE). We sought to analyze the pattern of this complication and compare it with the SPTE experienced in our patients treated with fractionated stereotactic radiotherapy. METHODS From January 2003 to October 2005, 32 patients with CPS meningiomas were treated. Thirty patients with a total of 38 lesions had sufficient follow-up for analysis. Group A (n = 14) patients were treated with single fraction SRS, and Group B (n = 16) patients were treated with fractionated stereotactic radiotherapy. The lesion volume was different between the two groups with the Group B median volume (7.46 cm3) being larger than that for Group A (2.84 cm3) (P = 0.0008). Conversely age, follow-up, sex, prior surgical events, number of lesions, tumor location, and atypical histology did not differ between these groups. The median marginal dose for patients in Group A was 14 Gy (range, 12.5–18 Gy). For Group B, six patients received a median marginal dose of 50.4 Gy in 28 fractions, and 10 patients received a marginal dose of 25 Gy in five fractions. RESULTS Seven of the 30 patients treated in this series developed posttreatment SPTE. The incidence of SPTE in Group A (six of 14 patients) was significantly higher than that in Group B (one of 16 patients) (P = 0.031). The median time to onset of SPTE in the six patients in Group A was 4 months. In Group B, one patient had onset of SPTE in 3 months. On univariate analysis, larger tumor volume (P = 0.0014) and tumor margin dose >14 Gy in patients undergoing SRS (P = 0.031) was associated with onset of SPTE. Age, previous surgery, and tumor location were not associated with onset of SPTE. CONCLUSION Despite larger lesion volumes, fractionated stereotactic radiotherapy is associated with less risk of posttreatment SPTE than SRS for patients with CPS meningiomas in our series. For patients treated with SRS, smaller volume and dose <14 Gy seems to be safe. Longer follow-up will be required to compare late complications and tumor control rates in these patients.



2004 ◽  
Vol 101 (Supplement3) ◽  
pp. 362-372 ◽  
Author(s):  
Michael T. Selch ◽  
Alessandro Pedroso ◽  
Steve P. Lee ◽  
Timothy D. Solberg ◽  
Nzhde Agazaryan ◽  
...  

Object. The authors sought to assess the safety and efficacy of stereotactic radiotherapy when using a linear accelerator equipped with a micromultileaf collimator for the treatment of patients with acoustic neuromas. Methods. Fifty patients harboring acoustic neuromas were treated with stereotactic radiotherapy between September 1997 and June 2003. Two patients were lost to follow-up review. Patient age ranged from 20 to 76 years (median 59 years), and none had neurofibromatosis. Forty-two patients had useful hearing prior to stereotactic radiotherapy. The fifth and seventh cranial nerve functions were normal in 44 and 46 patients, respectively. Tumor volume ranged from 0.3 to 19.25 ml (median 2.51 ml). The largest tumor dimension varied from 0.6 to 4 cm (median 2.2 cm). Treatment planning in all patients included computerized tomography and magnetic resonance image fusion and beam shaping by using a micromultileaf collimator. The planning target volume included the contrast-enhancing tumor mass and a margin of normal tissue varying from 1 to 3 mm (median 2 mm). All tumors were treated with 6-MV photons and received 54 Gy prescribed at the 90% isodose line encompassing the planning target volume. A sustained increase greater than 2 mm in any tumor dimension was defined as local relapse. The follow-up duration varied from 6 to 74 months (median 36 months). The local tumor control rate in the 48 patients available for follow up was 100%. Central tumor hypodensity occurred in 32 patients (67%) at a median of 6 months following stereotactic radiotherapy. In 12 patients (25%), tumor size increased 1 to 2 mm at a median of 6 months following stereotactic radiotherapy. Increased tumor size in six of these patients was transient. In 13 patients (27%), tumor size decreased 1 to 14 mm at a median of 6 months after treatment. Useful hearing was preserved in 39 patients (93%). New facial numbness occurred in one patient (2.2%) with normal fifth cranial nerve function prior to stereotactic radiotherapy. New facial palsy occurred in one patient (2.1%) with normal seventh cranial nerve function prior to treatment. No patient's pretreatment dysfunction of the fifth or seventh cranial nerve worsened after stereotactic radiotherapy. Tinnitus improved in six patients and worsened in two. Conclusions. Stereotactic radiotherapy using field shaping for the treatment of acoustic neuromas achieves high rates of tumor control and preservation of useful hearing. The technique produces low rates of damage to the fifth and seventh cranial nerves. Long-term follow-up studies are necessary to confirm these findings.



Neurosurgery ◽  
2004 ◽  
Vol 55 (3) ◽  
pp. 519-531 ◽  
Author(s):  
Erol Veznedaroglu ◽  
David W. Andrews ◽  
Ronald P. Benitez ◽  
M. Beverly Downes ◽  
Maria Werner-Wasik ◽  
...  

Abstract OBJECTIVE: Despite the success of stereotactic radiosurgery, large inoperable arteriovenous malformations (AVMs) of 14 cm3 or more have remained largely refractory to stereotactic radiosurgery, with much lower obliteration rates. We review treatment of large AVMs either previously untreated or partially obliterated by embolization with fractionated stereotactic radiotherapy (FSR) regimens using a dedicated linear accelerator (LINAC). METHODS: Before treatment, all patients were discussed at a multidisciplinary radiosurgery board and found to be suitable for FSR. All patients were evaluated for pre-embolization. Those who had feeding pedicles amenable to glue embolization were treated. LINAC technique involved acquisition of a stereotactic angiogram in a relocatable frame that was also used for head localization during treatment. The FSR technique involved the use of six 7-Gy fractions delivered on alternate days over a 2-week period, and this was subsequently dropped to 5-Gy fractions after late complications in one of seven patients treated with 7-Gy fractions. Treatments were based exclusively on digitized biplanar stereotactic angiographic data. We used a Varian 600SR LINAC (Varian Medical Systems, Inc., Palo Alto, CA) and XKnife treatment planning software (Radionics, Inc., Burlington, MA). In most cases, one isocenter was used, and conformality was established by non-coplanar arc beam shaping and differential beam weighting. RESULTS: Thirty patients with large AVMs were treated between January 1995 and August 1998. Seven patients were treated with 42-Gy/7-Gy fractions, with one patient lost to follow-up and the remaining six with previous partial embolization. Twenty-three patients were treated with 30-Gy/5-Gy fractions, with two patients lost to follow-up and three who died as a result of unrelated causes. Of 18 evaluable patients, 8 had previous partial embolization. Mean AVM volumes at FSR treatment were 23.8 and 14.5 cm3, respectively, for the 42-Gy/7-Gy fraction and 30-Gy/5-Gy fraction groups. After embolization, 18 patients still had AVM niduses of 14 cm3 or more: 6 in the 7-Gy cohort and 12 in the 5-Gy cohort. For patients with at least 5-year follow-up, angiographically documented AVM obliteration rates were 83% for the 42-Gy/7-Gy fraction group, with a mean latency of 108 weeks (5 of 6 evaluable patients), and 22% for the 30-Gy/5-Gy fraction group, with an average latency of 191 weeks (4 of 18 evaluable patients) (P = 0.018). For AVMs that remained at 14 cm3 or more after embolization (5 of 6 patients), the obliteration rate remained 80% (4 of 5 patients) for the 7-Gy cohort and dropped to 9% for the 5-Gy cohort. A cumulative hazard plot revealed a 7.2-fold greater likelihood of obliteration with the 42-Gy/7-Gy fraction protocol (P = 0.0001), which increased to a 17-fold greater likelihood for postembolization AVMs of 14 cm3 or more (P = 0.003). CONCLUSION: FSR achieves obliteration for AVMs at a threshold dose, including large residual niduses after embolization. With significant treatment-related morbidities, further investigation warrants a need for better three-dimensional target definition with higher dose conformality.



Neurosurgery ◽  
2011 ◽  
Vol 68 (4) ◽  
pp. 974-984 ◽  
Author(s):  
Matthew M. Kimball ◽  
Kelly D. Foote ◽  
Frank J. Bova ◽  
Yueh-Yun Chi ◽  
William A. Friedman

Abstract BACKGROUND: Nonvestibular schwannomas are uncommon tumors of the brain often treated by surgical resection. Surgery may be associated with high morbidity. OBJECTIVE: We present a series of nonvestibular schwannomas treated with linear accelerator radiosurgery during a 19-year period. METHODS: This is a retrospective analysis of patients who underwent treatment of nonvestibular schwannomas at the University of Florida with linear accelerator radiosurgery between August 1989 and February 2008. Forty-nine patients underwent treatment during the study period, and 6 were lost to follow up. The mean age was 51 years (range, 17-82 years), 39% had previous surgical resection, and 67% presented with preradiosurgery cranial nerve deficits. There were 25 trigeminal, 18 jugular foramen, 2 facial, 2 oculomotor, 1 hypoglossal, and 1 high cervical schwannomas. The median tumor volume was 5.3 mL (range, 0.3-24.5 mL), treated with a median dose of 1250 cGy (range, 1000-1500 cGy). Study endpoints were actuarial local tumor control and neurological outcome. RESULTS: Forty-three patients were available for a median follow-up of 37 months (range, 6-210 months). Actuarial local tumor control was 97% at 1 year, 91% at 4.5 years, and 83% at 5 years. There were 4 new cranial nerve deficits (9%) including facial numbness (2 patients), anesthesia dolorosa (1 patient), and facial weakness (1 patient). Thirty-nine percent had documented clinical and/or symptomatic improvement. There were no other morbidity and no mortality with treatment. CONCLUSION: Radiosurgery for nonvestibular schwannomas offers good actuarial local tumor control and has superior morbidity compared with surgical resection. This is the largest linear accelerator radiosurgical series, and the second largest radiosurgical series reported to date.



Neurosurgery ◽  
2013 ◽  
Vol 73 (3) ◽  
pp. 489-496 ◽  
Author(s):  
Colin E. Champ ◽  
Xinglei Shen ◽  
Wenyin Shi ◽  
Sonal U. Mayekar ◽  
Katherine Chapman ◽  
...  

Abstract BACKGROUND: Fractionated stereotactic radiotherapy (FSRT) is a noninvasive treatment for acoustic neuromas (ANs). Initial reports from our institution demonstrated that the reduction of treatment dose to 46.8 Gy resulted in improved preservation of functional hearing status. OBJECTIVE: We now report the tumor control (TC), symptomatic outcome, and hearing preservation (HP) rate in patients treated with reduced-dose FSRT. METHODS: We analyzed all patients with AN treated from 2002 to 2011. All patients received 46.8 Gy in 1.8-Gy fractions. Follow-up audiogram and magnetic resonance imaging were performed in ⩽1-year intervals. TC and HP were calculated by the Kaplan-Meier method. Analysis of HP, defined as Gardner-Robertson value ⩽2, was determined by audiometric data. Non-hearing-related symptoms were defined by Common Terminology Criteria for Adverse Events version 4. RESULTS: In total, 154 patients were analyzed. At a median follow-up of 35 months (range, 4-108), TC was achieved in 96% of patients (n = 148/154) and at 3 and 5 years was 99% and 93%. Eighty-seven patients had serviceable hearing at the time of FSRT and evaluable audiometric follow-up. Overall HP was 67% and at 3 and 5 years was 66% and 54%. Pure tone average decreased by a median of 13 dB in all patients. Nineteen percent (n = 31) of patients experienced symptom improvement, and 8% (n = 13) had worsening of symptoms. Cranial nerve dysfunction occurred in 3.8% of patients (n = 6). CONCLUSION: Reduced-dose FSRT to 46.8 Gy for AN achieves excellent functional HP rates and limited toxicity without compromising long-term TC. Based on these promising outcomes, further attempts at dose deescalation may be warranted.



2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Leor Zach ◽  
Amir Agami ◽  
Orit Furman ◽  
Moshe Attia ◽  
Zvi Cohen ◽  
...  

Abstract Background Most anterior visual pathway meningiomas (AVPM) are benign and slow-growing, but these tumors may affect visual functions, including visual acuity (VA) and visual field (VF). Due to location, most are treated non-surgically by fractionated stereotactic radiotherapy (FSRT), aiming to prevent tumor progression and visual functions deterioration. Unfortunately, FSRT in itself may affect visual functions. The current preferred treatment regimen (in terms of safety and effectiveness) is undetermined. While most cases are treated with conventional fractionation (cFSRT)—50.4–54 Gy in 28–30 fractions of 1.8–2 Gy, advances in technology have allowed shortening of total treatment length to hypofractionation (hSRT)—25-27 Gy in 3–5 fractions of 5–9 Gy. Our aim was to evaluate the association of radiotherapy regimen for treating AVPM (cFSRT vs. hSRT) with visual function outcomes (VA, VF) at the last neuro-ophthalmologic evaluation. Methods We conducted a retrospective cohort study of AVPM cases treated at Sheba Medical Center during 2004–2015. We compared cFSRT and hSRT regimens regarding visual function (VA, VF) outcomes at the last neuro-ophthalmologic evaluation. VA was determined by the logarithm of the minimum angle of resolution (LogMAR). VF was determined by the mean deviation (MD). A clinically relevant change in VA was defined as 0.2 LogMAR. Results 48 patients (13 receiving hSRT, 35 receiving cFSRT) were included, with a median follow-up of 55 months. No significant difference was evident regarding LogMAR or MD of involved eyes at the last evaluation. Six (17%) patients in the cFSRT group experienced clinically relevant VA deterioration in the involved eye, compared with six (46%) in hSRT (p = 0.06). Conclusion Our findings, using comprehensive and meticulous investigation of visual outcomes, suggest that hSRT may be associated with higher risk for VA and VF deterioration in AVPM especially in ONSM. We recommend the use of cFSRT for ONSM.





Neurosurgery ◽  
2005 ◽  
Vol 56 (6) ◽  
pp. 1254-1263 ◽  
Author(s):  
Steven D. Chang ◽  
Iris C. Gibbs ◽  
Gordon T. Sakamoto ◽  
Elizabeth Lee ◽  
Adetokunbo Oyelese ◽  
...  

Abstract OBJECTIVE: Stereotactic radiosurgery has proven effective in the treatment of acoustic neuromas. Prior reports using single-stage radiosurgery consistently have shown excellent tumor control, but only up to a 50 to 73% likelihood of maintaining hearing at pretreatment levels. Staged, frame-based radiosurgery using 12-hour interfraction intervals previously has been shown by our group to achieve excellent tumor control while increasing the rate of hearing preservation at 2 years to 77%. The arrival of CyberKnife (Accuray, Inc., Sunnyvale, CA) image-guided radiosurgery now makes it more practical to treat acoustic neuroma with a staged approach. We hypothesize that such factors may further minimize injury of adjacent cranial nerves. In this retrospective study, we report our experience with staged radiosurgery for managing acoustic neuromas. METHODS: Since 1999, the CyberKnife has been used to treat more than 270 patients with acoustic neuroma at Stanford University. Sixty-one of these patients have now been followed up for a minimum of 36 months and form the basis for the present clinical investigation. Among the treated patients, the mean transverse tumor diameter was 18.5 mm, whereas the total marginal dose was either 18 or 21 Gy using three 6- or 7-Gy fractions. Audiograms and magnetic resonance imaging were obtained at 6-months intervals after treatment for the first 2 years and then annually thereafter. RESULTS: Of the 61 patients with a minimum of 36 months of follow-up (mean, 48 mo), 74% of patients with serviceable hearing (Gardner-Robinson Class 1–2) maintained serviceable hearing at the last follow-up, and no patient with at least some hearing before treatment lost all hearing on the treated side. Only one treated tumor (2%) progressed after radiosurgery; 29 (48%) of 61 decreased in size and 31 (50%) of the 61 tumors were stable. In no patients did new trigeminal dysfunction develop, nor did any patient experience permanent injury to their facial nerve; two patients experienced transient facial twitching that resolved in 3 to 5 months. CONCLUSION: Although still preliminary, these results indicate that improved tumor dose homogeneity and a staged treatment regimen may improve hearing preservation in acoustic neuroma patients undergoing stereotactic radiosurgery.



2011 ◽  
Vol 115 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Philipp Taussky ◽  
Ricky Kalra ◽  
Jeroen Coppens ◽  
Jahan Mohebali ◽  
Randy Jensen ◽  
...  

Object Stereotactic radiosurgery and fractionated stereotactic radiotherapy are commonly used in the treatment of residual or recurrent benign tumors of the skull base and cavernous sinus. A major risk associated with radiosurgical or radiotherapy treatment of residual or recurrent tumors adjacent to normal functional pituitary gland is radiation of the pituitary, which frequently leads to the development of hypopituitarism. The authors have used a technique of pituitary transposition to reduce the radiation dose to the normal pituitary gland in cases of planned radiosurgical treatment of residual tumor within the cavernous sinus. Here, the authors analyze the long-term endocrinological outcomes in patients with residual and recurrent tumors who undergo hypophysopexy and adjuvant radiosurgical or conformal fractionated radiotherapy treatment. Methods Pituitary transposition involves placement of a fat graft between the normal pituitary gland and residual tumor in the cavernous sinus. A sellar exploration for tumor resection is performed, the pituitary gland is transposed from the region of the cavernous sinus, and the graft is interposed between the pituitary gland and the residual tumor. The residual tumor may then be treated with stereotactic radiosurgery or conformal fractionated radiation therapy. The authors evaluated endocrinological outcome, safety of the procedure, and postoperative complications in patients who underwent this procedure during a 7-year period. Results Hypophysopexy has been used in 34 patients with nonfunctioning pituitary adenomas (19), functional pituitary adenomas (8), chordomas (2), meningiomas (2), chondrosarcoma (1), hemangiopericytoma (1), or hemangioma (1) involving the sella and cavernous sinus. Follow-up (radiographic and endocrinological) has been performed yearly in all patients. Two patients experienced postoperative endocrine deficits before radiosurgery (1 transient), but none of the patients developed new hypopituitarism during the median 4-year follow-up (range 1–8 years) after radiosurgery or fractionated stereotactic radiotherapy. Conclusions The increased distance between the normal pituitary gland and the residual tumor facilitates treatment of the tumor with radiosurgery or radiotherapy and effectively reduces the incidence of radiation injury to the normal pituitary gland when compared with historical controls.



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