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PubMedDate not supplied

Radiosurgery for the treatment of brain metastases.

Surgical resection and whole brain radiotherapy (WBRT) have been the mainstays of the treatment of cerebral metastases. This approach results in a median survival of about 10 months. Several recent publications and our own experience suggest that a similar median survival can be achieved with stereotactic radiosurgery using either the Leksell Gamma Knife or the linear accelerator radiosurgical techniques. In addition, radiosurgery can effectively treat metastatic tumors in surgically inaccessible sites, e.g., the brainstem. Radiosurgery can also effectively treat multiple intracranial metastases in widely separated areas of the brain. In fact, we have shown that patients with multiple metastases have similar lengths and qualities of survival as do patients with single metastases treated with stereotactic radiosurgery. The most important predictor of success in radiosurgical treatment of cerebral metastases is the neurological status of the patient, usually expressed as the Karnofsky Performance Status (KPS). The histological type of primary cancer is not an outcome predictor. Even so-called "radioresistant" tumors (e.g., melanoma, renal cell) respond favorable to radiosurgery. A great benefit of radiosurgery is the virtual lack of perioperative complications and the minimal interference with quality of life compared either to surgery or to fractionated whole brain radiotherapy. Long-term complications of radiosurgery are infrequent and primarily relate to failure of local tumor control (10%) and radiation-induced edema or necrosis. The later usually can be controlled with corticosteroids, but occasionally, craniotomy may be required to treat life-threatening mass effects. We believe that radiosurgery is the treatment of choice for most cerebral metastases. Only large lesions (> 3.5-4 cm diameter) and those which require immediate decompression to treat life-threatening mass effects require surgical treatment. Radiosurgery also may be used to treat residual disease after surgical resection. We have shown that WBRT does not increase the efficacy of radiosurgery in the treatment of cerebral metastases, and, therefore, we prefer to avoid both the short- and long-term morbidity of that treatment, if possible.

Brain Neoplasms↗

PubMed2001

Salvage treatment for persistent and recurrent T1-2 nasopharyngeal carcinoma by stereotactic radiosurgery.

OBJECTIVE: To study the efficacy of stereotactic radiosurgery in salvaging early-stage persistent and recurrent nasopharyngeal carcinoma (NPC) after primary radiotherapy. METHODS: A prospective single-arm study evaluating the response and outcome of patients with rT1-2 NPC treated by stereotactic radiosurgery. Eleven patients with rT1-2 were treated by radiosurgery between March 1998 and March 2000. Four patients were treated for persistent disease occurring within 4 months after primary radiotherapy, six were treated for first recurrence, and one for third recurrence. Six patients had rT1 disease and five had rT2 disease. Most patients had disease not amenable to brachytherapy, surgery, or external re-irradiation. The median target volume was 5.8 cc (range, 3.3-16.9). Radiosurgery was performed with multiple noncoplanar arcs of photon, with a median dose of 12.5 Gy delivered to the 80% isodose line (range, 12-14 Gy). Median follow-up time after radiosurgery was 18 months (range, 9-30). RESULTS: Nine patients had complete regression of tumor as assessed by imaging, nasopharyngoscopy, and biopsy; one patient had partial regression of tumor; whereas one patient had static disease. The overall response rate was 91% (10 of 11) and the complete response rate was 82% (9 of 11). Two patients with complete response subsequently had local relapse develop, with one recurrence outside the treated volume 8 months after radiosurgery, and the other within the treated volume 6 months after radiosurgery. One patient with a partial response had neck node recurrence develop. Temporal lobe necrosis occurred in one patient but probably represents sequelae of primary radiation after reviewing the dosimetry. Ten patients are still alive, whereas one patient with local relapse had distant metastases develop and died. The estimated 1-year local control rate after radiosurgery was 82%. CONCLUSIONS: Our preliminary results indicate that stereotactic radiosurgery is an effective treatment modality for persistent and recurrent T1-T2 NPC, and early control rate seems to be comparable to other salvage treatments. More clinical experiences and longer follow-up are still needed to validate our results and to address fully the role of radiosurgery in salvaging local failures of NPC.

Adult↗

PubMed1993

Conventional fractionated radiation therapy vs. radiosurgery for selected benign intracranial lesions (arteriovenous malformations, pituitary adenomas, and acoustic neuromas).

Despite growing interest in radiosurgery, the precise role of radiosurgery relative to that of conventional fractionated external-beam radiation therapy is not fully clear. A critical review of the available data suggests that radiosurgery is both a safe and effective treatment for small arteriovenous malformations, pituitary adenomas and acoustic neuromas. For arteriovenous malformations, the effectiveness of radiosurgery is clearly reduced as the size of the malformation increases. Conventional external-beam radiation therapy is also an effective treatment for pituitary adenomas and acoustic neuromas, while the results for arteriovenous malformations are less encouraging. However, most arteriovenous malformations that have been treated with fractionated radiation therapy were large and received relatively low doses of radiation. One can speculate that high doses (> or = 50 Gy) of fractionated radiation therapy may be effective in the treatment of small arteriovenous malformations. Differences in the apparent effectiveness of radiosurgery and conventional fractionated radiation therapy are partly due to patient selection. A single fraction of approximately 20 Gy (a dose frequently used during radiosurgery) is probably 'biologically equivalent' to approximately 50 to 110 Gy of fractionated radiation therapy (at 2 Gy/fraction based on the linear quadratic model). In this regard, radiosurgery may be just a means of dose escalation. It remains to be shown that the possible benefit of radiosurgery could not be achieved by simply escalating the doses of fractionated radiation. Further clinical experience is needed to better define the role of radiosurgery. Randomized trials comparing conventional fractionated radiation vs. radiosurgery at approximately equal complication levels may be possible.

Adenoma↗

PubMed1999

[Stereotactic one-time irradiation (radiosurgery). The methods, indications and results].

BACKGROUND: Stereotaxy is a method to determine a point in the patient's body by an external coordinate system which is attached to the patient. Radiosurgery uses this method for precise delivery of a high single radiation dose to the patient. The aim is to destroy the tissue in the target and to spare surrounding unaffected normal tissue by a steep dose gradient. METHODS: Three techniques of percutaneous radiosurgery are available: radiosurgery with ion beams with a cyclotron, spherical arrangement of cobalt-60 sources, the so-called gamma knife, and an adapted linear accelerator. The availability and the good clinical experience lead to a wide spread use of linear accelerator for radiosurgery in recent years. A subsequent development is fractionated stereotactic radiotherapy which combines the precision of radiosurgery with the radiobiological advantage of fractionation. RESULTS: Only a few indications for radiosurgery are proven by statistically valid studies. One of these is the treatment of small arteriovenous malformation, where obliteration rates of 80% to 100% are reported with only minor toxicity. However, the obliteration rate is reduced significantly in large arteriovenous malformations. A local control rate of 90% is obtained after radiosurgery of brain metastases which is comparable to the results of microsurgical resection followed by adjuvant whole brain radiotherapy. An ongoing EORTC study evaluates the role of adjuvant whole brain radiotherapy after radiosurgery. The survival of the patients with brain metastases is limited by the existence of progressive extracerebral disease. The role of radiosurgery in the treatment of benign tumors is currently evaluated in clinical studies which include: vestibular schwannomas, meningiomas, chordomas and chondrosarcomas and pituitary adenomas. Most of the published studies include only small tumors because radiosurgery is limited by the risk of radionecrosis of adjacent normal tissue, which shows a steep dose volume response relationship. Recent developments of stereotactic radiotherapy include the use of mini-multileaf-collimators and clinical studies on stereotactic radiotherapy of extracranial targets. CONCLUSIONS: Stereotactic irradiation is a well established treatment technique for intracranial tumors and arteriovenous malformations. Methods are available that allow optimization of dose distributions to irregularly shaped tumors for single dose as well as fractionated stereotactic irradiations by linear accelerator. Therefore the therapeutic potential of this technique has increased and enables also the extracerebral application in controlled clinical studies.

Brain Neoplasms↗

PubMed2004

Linac radiosurgery versus whole brain radiotherapy for brain metastases. A survival comparison based on the RTOG recursive partitioning analysis.

BACKGROUND AND PURPOSE: For patients with inoperable brain metastases, whole brain radiotherapy (WBRT) has been the standard treatment for decades. Radiosurgery is an effective alternative strategy, but has failed to show a substantial survival benefit so far. The prognostic factors derived from the RTOG recursive partitioning analysis (RPA) provide a framework that allows a nonrandomized comparison of the two modalities. PATIENTS AND METHODS: From 1991 to 1998, 117 patients with one to three previously untreated cerebral metastases underwent single-dose linac radiosurgery (median dose 20 Gy) without adjuvant WBRT. After radiosurgery, 26/117 patients (22%) had salvage WBRT, radiosurgery or neurosurgical resection of recurrent (4/117) and/or new (24/117) metastases. Survival of these patients was compared to a historical group of 138 patients with one to three lesions treated by WBRT (30-36 Gy/3-Gy fractions) from 1978 to 1991; only nine of these patients (7%) had salvage WBRT. All patients were classified into the three RPA prognostic classes based on age, performance score, and presence of extracranial tumor manifestations. RESULTS: In RPA class I (Karnofsky performance score > or = 70, primary tumor controlled, no other metastases, age < 65 years), radiosurgery resulted in a median survival of 25.4 months (n = 23, confidence interval [CI] 5.8-45.0) which was significantly longer than for WBRT (n = 9, 4.7 months, CI 3.8-5.5; p < 0.0001). In RPA class III (Karnofsky performance score < 70), no significant difference in survival between radiosurgery (n = 20, 4.2 months, CI 3.2-5.3) and WBRT (n = 68, 2.5 months, CI 2.2-2.8) was found. In RPA class II (all other patients), radiosurgery produced a small, but significant survival advantage (radiosurgery: n = 74, 5.9 months, CI 3.2-8.5, WBRT: n = 61, 4.1 months, CI 3.4-4.9; p < 0.04). CONCLUSION: Radiosurgery in patients with one to three cerebral metastases results in a substantial survival benefit only in younger patients with a low systemic tumor burden when compared to WBRT alone. It cannot be excluded that this effect is partially caused by the available salvage options after radiosurgery.

Adult↗

PubMed2005

Multidisciplinary treatment of cavernous sinus dural arteriovenous fistulae with radiosurgery and embolization.

OBJECTIVE: With the advent of interventional neuroradiology and stereotactic radiosurgery, dural arteriovenous fistulae are less often managed with open surgery. We evaluated the outcome of dural arteriovenous fistulae of the cavernous sinus treated with a combination of radiosurgery and embolization. MATERIAL AND METHODS: Twenty dural arteriovenous fistulae located in the cavernous sinus were enrolled in our study. Fifteen patients received X-knife radiosurgery alone and 5 also required embolization, one before radiosurgery and 4 after radiosurgery. The mean volume of the lesions was 2.8 ml (range 0.2-12.6), the corresponding radiation volume was 6.5 ml (range 0.6-24.6), and the conformity index was 2.9 (range 1.8-5.3). The mean peripheral and maximum radiation dose was 17.8 Gy (range 17-20) and 28.3 Gy (range 19-37) Gy, respectively. The clinical and imaging data were analyzed. RESULTS: The mean follow up period was 29 months (23-39). Seventy-five percent (15/20) of patients receiving radiosurgery alone achieved a symptomatic cure and with additional embolization 90% (18/20) were cured. All patients achieved cure on imaging after radiosurgery alone or in combination with embolization. Abnormal imaging findings were observed in two patients after treatment, one had an intracerebral hemorrhage and the other radiation edema, but both were asymptomatic. CONCLUSION: With multidisciplinary treatment with combined radiosurgery and embolization, satisfactory results can be achieved for dural arteriovenous fistulae with a low complication rate. In patients with mild symptoms, radiosurgery is the initial treatment option. Embolization should be performed in patients with severe symptoms or who have failed radiosurgery.

Adult↗

PubMed2005

Radiosurgery for dural arteriovenous fistulas.

OBJECTIVE: Dural arteriovenous fistulas (DAVFs) comprise 10% to 15% of all arteriovenous malformations. Recent studies have demonstrated promising results when radiosurgery is used for DAVFs. We retrospectively analyzed our patients with DAVFs who received stereotactic radiosurgery with or without embolization. METHODS: Between 1991 and 2002, 18 patients with 23 angiographically confirmed symptomatic DAVFs underwent gamma knife radiosurgery, either alone (n = 8) or in combination with embolization (n = 10). A retrospective chart review was performed to identify DAVF location, venous drainage pattern, radiosurgery dosimetry, clinical outcomes, and imaging results. The series included 9 men and 9 women with a mean age of 65 (range 50-89) years. Nine patients received particulate, coil, and/or absolute ethanol embolization before radiosurgery, and 1 patient received particulate embolization after radiosurgery. The mean duration of clinical follow-up was 43 (range 2-116) months. The mean margin radiosurgery dose was 20 (range 15-30) Gy. RESULTS: Nine patients had complete resolution of their presenting symptoms, and 9 patients had resolution of all but 1 of their presenting symptoms. Angiographic follow-up (mean 46 months) was performed on 8 patients demonstrating complete obliteration in all the cases. Seven patients evaluated by magnetic resonance angiography or computed tomography angiography showed no evidence of DAVF (4 patients) or decreased DAVF size (3 patients). After radiosurgery, 1 patient developed a temporary hemiparesis. Two permanent neurological deficits occurred after embolization before radiosurgery. No patient had an intracranial hemorrhage after treatment. CONCLUSION: Stereotactic radiosurgery provides effective long-term relief of symptoms in selected patients with DAVFs.

Aged↗

PubMed2001

Transient enlargement of contrast uptake on MRI after linear accelerator (linac) stereotactic radiosurgery for brain metastases.

PURPOSE/OBJECTIVE: With the increasing number of patients successfully treated with stereotactic radiosurgery for brain metastases, decision making after therapy based on follow-up imaging findings becomes more and more important. Magnetic resonance imaging (MRI) is the most sensitive means for follow-up studies. The objective of this study was to investigate the treatment outcome of our radiosurgery program and to describe the response of brain metastases to contrast-enhanced MRI after linear accelerator (linac) stereotactic radiosurgery and identify factors to distinguish among local control and local failure. METHODS AND MATERIALS: Using serial MRI, we followed the course of 87 brain metastases in 48 consecutive patients treated between September 1996 and November 1997 with linac-based radiosurgery with 15-MV photons. Treatment planning was performed on an MR data cube. For spherical metastases, radiosurgery was delivered using a 9 noncoplanar arc technique with circular-shaped collimators. For irregularly shaped targets, radiosurgery was delivered using a manually driven multi-leaf collimator with a leaf width of 1.5 mm projected to the isocenter. Median radiosurgery dose was 20 Gy prescribed to the 80% isodose. Together with whole brain radiotherapy (20 x 2 Gy, 5/w), a median radiosurgical dose of 15 Gy was delivered. Median follow-up was 8 (range 2--36) months. Factors influencing local control and survival rates were analyzed with respect to MRI response, and Kaplan-Meier curves were calculated. RESULTS: Actuarial local tumor control was 91% at one and two years. Patient survival at one and two years was 30% and 18%. Median survival was 9 months. During follow-up in 70 (81%) of the 87 treated metastases, the contrast-enhancing volumes on T1W images were stable or disappeared partly or completely. A transient enlargement of contrast-enhancing volumes was observed in 11 (12%) of the 87 lesions treated, while a progressive enlargement due to local treatment failure was observed in 6 (7%) of the 87 treated metastases. Younger age, early contrast onset after radiosurgery, and previous chemotherapy were associated with this transient enlargement of contrast-enhancing lesion volume. CONCLUSIONS: Linac-based radiosurgery is an effective, noninvasive, and safe treatment option for patients with brain metastases. A marked enlargement of the contrast-enhancing volume on T(1)-weighted MR images after radiosurgery is a sensitive predictor for, but not equivalent with, local failure. In as many as two-thirds of the cases with contrast enlargement in MRI follow-up, the contrast enlargement is transient with no need for further treatment. While some MRI findings are more likely if transient enlargement is present, a clear decision cannot be made based on MRI, and ultimately the clinical status dictates further action.

Analysis of Variance↗

PubMed1999

Stereotactic radiosurgery plus whole brain radiotherapy versus radiotherapy alone for patients with multiple brain metastases.

PURPOSE: Multiple brain metastases are a common health problem, frequently diagnosed in patients with cancer. The prognosis, even after treatment with whole brain radiation therapy (WBRT), is poor with average expected survivals less than 6 months. Retrospective series of stereotactic radiosurgery have shown local control and survival benefits in case series of patients with solitary brain metastases. We hypothesized that radiosurgery plus WBRT would provide improved local brain tumor control over WBRT alone in patients with two to four brain metastases. METHODS: Patients with two to four brain metastases (all < or =25 mm diameter and known primary tumor type) were randomized to initial brain tumor management with WBRT alone (30 Gy in 12 fractions) or WBRT plus radiosurgery. Extent of extracranial cancer, tumor diameters on MRI scan, and functional status were recorded before and after initial care. RESULTS: The study was stopped at an interim evaluation at 60% accrual. Twenty-seven patients were randomized (14 to WBRT alone and 13 to WBRT plus radiosurgery). The groups were well matched to age, sex, tumor type, number of tumors, and extent of extracranial disease. The rate of local failure at 1 year was 100% after WBRT alone but only 8% in patients who had boost radiosurgery. The median time to local failure was 6 months after WBRT alone (95% confidence interval [CI], 3.5-8.5) in comparison to 36 months (95% CI, 15.6-57) after WBRT plus radiosurgery (p = 0.0005). The median time to any brain failure was improved in the radiosurgery group (p = 0.002). Tumor control did not depend on histology (p = 0.85), number of initial brain metastases (p = 0.25), or extent of extracranial disease (p = 0.26). Patients who received WBRT alone lived a median of 7.5 months, while those who received WBRT plus radiosurgery lived 11 months (p = 0.22). Survival did not depend on histology or number of tumors, but was related to extent of extracranial disease (p = 0.02). There was no neurologic or systemic morbidity related to stereotactic radiosurgery. CONCLUSIONS: Combined WBRT and radiosurgery for patients with two to four brain metastases significantly improves control of brain disease. WBRT alone does not provide lasting and effective care for most patients.

Adult↗

PubMed2002

Radiosurgery for treatment of recurrent intracranial hemangiopericytomas.

OBJECTIVE: Hemangiopericytomas are highly aggressive meningeal tumors with tendencies for recurrence and metastasis. The purpose of this retrospective, single-institution review was to evaluate the efficacy and role of stereotactic radiosurgery in the management of recurrent hemangiopericytomas. METHODS: We reviewed data for patients who underwent stereotactic radiosurgery at the University of Pittsburgh between 1987 and 2001. Fourteen patients underwent radiosurgery for 15 discrete tumors. Prior treatments included transsphenoidal resection (n = 1), craniotomy and resection (n = 27), embolization (n = 1), and conventional radiotherapy (n = 7). Clinical and radiological responses were evaluated. Follow-up periods varied from 5 to 76 months (mean, 31.3 mo; median, 21 mo). The mean radiation dose to the tumor margin was 15 Gy. RESULTS: Seventy-nine percent of patients (11 of 14 patients) with recurrent hemangiopericytomas demonstrated local tumor control after radiosurgery. Twelve of 15 tumors (i.e., 80%) dramatically decreased in size on follow-up imaging scans. Regional intracranial recurrences were retreated with radiosurgery for two patients (i.e., 15%); neither of those two patients experienced long-term tumor control. Local recurrences occurred 12 to 75 months (median, 21 mo) after radiosurgery. Local tumor control and survival rates at 5 years after radiosurgery were 76 and 100%, respectively (Kaplan-Meier method). We could not correlate prior irradiation or tumor size with tumor control. Twenty-nine percent of the patients (4 of 14 patients) developed remote metastases. Radiosurgery did not seem to offer protection against the development of intra- or extracranial metastases. CONCLUSION: Gamma knife radiosurgery provided local tumor control for 80% of recurrent hemangiopericytomas. When residual tumor is identified after resection or radiotherapy, early radiosurgery should be considered as a feasible treatment modality. Despite local tumor control, patients are still at risk for distant metastasis. Diligent clinical and radiological follow-up monitoring is necessary.

Adolescent↗

PubMed1998

Gamma knife radiosurgery as the first surgery for trigeminal neuralgia.

To evaluate the role of Gamma Knife radiosurgery as the first surgical therapy in the management of medically refractory trigeminal neuralgia, we reviewed outcomes on our first 23 patients who had radiosurgery as primary surgical therapy. These patients represented 19% of our overall series. Mean patient age was 66 years, and mean follow-up after radiosurgery was 12 months (range 5-33 months). For most patients, radiosurgery was performed because the patient had medical contraindications to open surgery. 14 patients had 70-Gy radiosurgery, and 9 patients, 80 Gy. Radiosurgery was performed using a single 4 mm isocenter. Postoperative imaging 6 to 9 months following radiosurgery confirmed regions of enhancement at the radiosurgical target. Nine patients received 70 Gy, and 8 patients had 80 Gy. 17 patients (74%) had an excellent result (total pain relief). Five patients (22%) achieved a good result (50-90% improvement). One patient had a poor result (4%) after 70-Gy radiosurgery and subsequently underwent microvascular decompression. No patient developed facial numbness or any other complication after Gamma Knife radiosurgery. Gamma Knife radiosurgery using 70 or 80 Gy targeted to the proximal trigeminal nerve proved to be a safe and effective primary surgical therapy for medically refractory trigeminal neuralgia. The overall response rate (96%) was similar to that obtained with other surgical therapies performed as a first procedure.

Aged↗

PubMed2004

Radiosurgery as primary management for meningiomas extending into the internal auditory canal.

Stereotactic radiosurgery is increasingly utilized as primary management for patients with skull base meningiomas. This study reviews the results of stereotactic radiosurgery for patients with meningiomas extending into the internal auditory canal (IAC) to determine the risk of facial weakness or hearing loss. From 1990 to 2002, 16 patients had radiosurgery for meningiomas extending into the IAC. The median patient age was 63 years. Ten patients had symptoms of vestibulocochlear nerve dysfunction before radiosurgery. The median tumor volume was 5.1 cm3; the median tumor extension into the IAC was 7 mm (range, 3-12). The median tumor margin dose was 15 Gy. The median follow-up was 36 months. Ten meningiomas (63%) decreased in size, and 6 tumors were unchanged. No patient developed facial weakness. One patient (6%) had worsened facial sensation. Three of 14 patients (21%) with either normal hearing clinically (n = 5) or documented Gardner-Robertson class 1-2 before radiosurgery (n = 9) had decreased hearing after radiosurgery. The 1-, 2- and 5-year actuarial incidences of hearing preservation were 93, 84 and 42%, respectively. Three patients (19%) had improved hearing after radiosurgery. One patient with class 2 hearing improved to class 1; 2 patients with no speech discrimination before radiosurgery (class 5) improved to a class 3 status following the procedure. The risk of facial weakness or hearing loss is low after radiosurgery for patients with meningiomas extending into the IAC. Radiosurgery is an excellent alternative to surgical excision for meningiomas in this location, especially if a subtotal resection is likely or a hearing-sacrificing operation such as a translabyrinthine approach is contemplated.

Aged↗

PubMed1998

Vestibular schwannoma management. Part II. Failed radiosurgery and the role of delayed microsurgery.

OBJECT: The indications, operative findings, and outcomes of vestibular schwannoma microsurgery are controversial when it is performed after stereotactic radiosurgery. To address these issues, the authors reviewed the experience at two academic medical centers. METHODS: During a 10-year interval, 452 patients with unilateral vestibular schwannomas underwent gamma knife radiosurgery. Thirteen patients (2.9%) underwent delayed microsurgery at a median of 27 months (range 7-72 months) after they had undergone radiosurgery. Six of the 13 patients had undergone one or more microsurgical procedures before they underwent radiosurgery. The indications for surgery were tumor enlargement with stable symptoms in five patients, tumor enlargement with new or increased symptoms in five patients, and increased symptoms without evidence of tumor growth in three patients. Gross-total resection was achieved in seven patients and near-gross-total resection in four patients. The surgery was described as more difficult than that typically performed for schwannoma in eight patients, no different in four patients, and easier in one patient. At the last follow-up evaluation, three patients had normal or near-normal facial function, three patients had moderate facial dysfunction, and seven had facial palsies. Three patients were incapable of caring for themselves, and one patient died of progression of a malignant triton tumor. CONCLUSIONS: Failed radiosurgery in cases of vestibular schwannoma was rare. No clear relationship was demonstrated between the use of radiosurgery and the subsequent ease or difficulty of delayed microsurgery. Because some patients have temporary enlargement of their tumor after radiosurgery, the need for surgical resection after radiosurgery should be reviewed with the neurosurgeon who performed the radiosurgery and should be delayed until sustained tumor growth is confirmed. A subtotal tumor resection should be considered for patients who require surgical resection of their tumor after vestibular schwannoma radiosurgery.

Aged↗

PubMed2006

Radiosurgery for arteriovenous malformations in children.

OBJECT: The authors present the results of stereotactic radiosurgery performed in a consecutive series of children with arteriovenous malformations (AVMs) and analyze factors associated with successful radiosurgery for this condition. METHODS: Between 1990 and 2001, 38 patients 18 years of age or younger underwent radiosurgery for AVMs. The median patient age was 15 years; 20 patients (53%) had experienced a prior hemorrhage. Twenty-seven AVMs (71%) were Spetzler-Martin Grade III or higher; 16 patients (42%) had AVMs located in the basal ganglia, thalamus, or brainstem. The median AVM volume was 3.4 cm3. The median radiosurgery-based AVM score was 1.08 according to the following formula: AVM score = 0.1 volume (cm3) + 0.02 x age (years) + 0.3 x location (frontal/temporal = 0; parietal/occipital/corpus callosum/cerebellar = 1; basal ganglia/thalamus/brainstem = 2). The median follow-up period was 42 months. One patient (3%) had an intraventricular hemorrhage 26 months after radiosurgery but experienced no new deficit. No patient had a permanent radiation-related complication after radiosurgery. Twenty-six patients (68%) had excellent outcomes (as defined by complete obliteration of the AVM with no new deficit) after radiosurgical treatment (21 cases determined using angiography and five using magnetic resonance imaging). Twelve patients (32%) remained unchanged (incomplete obliteration but no new deficit). Univariate analysis found that patient age, AVM volume, location, or Spetzler-Martin grade did not correlate with excellent outcomes. Patients whose radiosurgery-based AVM scores were 1 or lower experienced an excellent outcome more frequently than patients with an AVM score higher than 1 (88% compared with 52%, p = 0.03). CONCLUSIONS: Radiosurgery was successful in the treatment of the majority of pediatric patients suffering from AVMs, and morbidity levels were minimal. The radiosurgery-based AVM grading scale accurately predicted these outcomes. Children whose AVMs are obliterated after radiosurgery should undergo repeated angiography after they reach adulthood to rule out the possibility of a recurrent nidus that would expose them to an ongoing risk of hemorrhage.

Adolescent↗

PubMed2001

[Evolution of epileptic seizures associated with cerebral arteriovenous malformations after radiosurgery].

The goal of this study is to evaluate the response of epileptic seizures associated with cerebral arteriovenous malformations following radiosurgery and determine the factors associated with a positive outcome. The series included 210 patients (123 men, 87 women) with a mean age of 33. One hundred seventy three patients out of 210 were controlled after radiosurgery. Seizures completely disappeared in 58% of cases and decreased in 18%. Anti-epileptic treatment was stopped in 44%. Sex and age upon seizure appearance were not found as determining factors in patients whose seizures disappeared after radiosurgery. Generalized seizures disappeared following radiosurgery in 90.7%, partial secondary generalized seizures in 53.5%, and partial seizures in only 39.6%. Frontal or temporal malformations are associated with a better response after radiosurgery than sylvian or rolandic location. Seizure disappearance was maximal in case of isolated seizure prior to the radiosurgery (84.4%), was reduced to 61.2% when seizures were limited to 2 to 20, and disappeared in 21.4% in severe seizures. Epilepsy present less than 3 years prior to radiosurgery disappeared in 71.9%; was reduced to 45% when the delay was over 3 years. Seizures disappeared in 64.4% when the malformation was obliterated, they were reduced to 46.9% when malformations persisted. The persistence of severe seizures following radiosurgery was linked to persistence of the malformation. On the other hand early seizures occurred in 3.3% during the first 48 hours following radiosurgery; they disappeared in 72.2% after that period. De novo seizures also occurred in 1.7% and disappeared in all these cases. In conclusion, seizures associated with cerebral arteriovenous malformations respond well to radiosurgery; the malformation obliteration evokes its association with the seizure; the seizure disappearance in spite of persistence of the malformation evokes the positive effect of radiotherapy on epileptic seizures.

Adolescent↗

PubMed2001

Acute effects of stereotactic radiosurgery on the kinetics of glucose metabolism in metastatic brain tumors: FDG PET study.

UNLABELLED: Hyperacute changes in the expression of glycolysis-associate gene products as well as FDG uptake in tumor cells after high-dose irradiation reflect response of the cells to noxious intervention and may be a potential indicator of the outcome of treatment. To understand acute effects on the kinetics of glucose metabolism of tumors in vivo after high-dose irradiation, we analyzed dynamic FDG PET data in patients with metastatic brain tumors receiving stereotactic radiosurgery. MATERIALS AND METHODS: We studied 5 patients with metastatic brain tumors by means of dynamic FDG PET before and 4 hours after stereotactic radiosurgery. Rate constants of glucose metabolism (K1*- k3*) were determined in a total of 13 tumors by a non-linear least squares fitting method for dynamic PET and arterial blood sampling data. Rate constants after radiosurgery were compared with those before radiosurgery. Changes in the rate constants induced by the therapy were also correlated with changes in tumor size evaluated by CT and/or MRI 6 months later. RESULTS: Four hours after radiosurgery, the phosphorylation rate indicated by k3* was significantly higher (0.080 +/- 0.058) than that before radiosurgery (0.049 +/- 0.023) (p < 0.05, paired t test), but there was no significant change in the membrane transport rates indicated by K1* and k2*. Although increases in the net influx rate constant K* (= K1*k3*/(k2* + k3*)) were correlated with increases in k3*, K* after radiosurgery (0.027 +/- 0.011) was not significantly different from that before the therapy (0.024 +/- 0.012). The reduction in the tumor size was correlated with k3* after radiosurgery. CONCLUSION: Acceleration of the phosphorylation process was demonstrated in vivo in metastatic brain tumors as early as 4 hours after stereotactic radiosurgery, as shown experimentally in vitro in a previous report. The phenomenon may be a sensitive indicator of cell damage.

Aged↗

PubMed2001

Linac radiosurgery for skull base meningiomas.

INTRODUCTION: Skull base meningiomas present a difficult surgical challenge because of the high potential morbidity of radical surgical extirpation and their low potential for incapacitating symptomatology. The focal character of meningiomas makes stereotactic radiosurgery an attractive adjuvant treatment modality to resection. The purpose of this study was to evaluate the local control rates and complications in 56 patients with base of skull meningiomas undergoing radiosurgery. METHODS: Patients underwent radiosurgery using the dedicated stereotactic linear accelerator at the Brigham and Women's Hospital. Minimal peripheral doses of radiosurgery ranged from 12 to 18.5 Gy (mean 15 Gy). Doses were designed to conform to the frequently irregular tumor volumes using the X-Knife treatment planning system. Multiple isocenters were used when required to increase conformality of dose. For 36 patients (64%), radiosurgery was used as an adjunct to surgery; for 20 patients (36%) it was the primary treatment. RESULTS: Median followup was five years. Nineteen patients (34%) were improved clinically at follow-up; 32 (57%) were unchanged; and 5 patients (9%) developed new or worsened neurologic deficits. Serial imaging studies after radiosurgery showed a reduction in tumor volume in 23 patients (41%); 30 (54%) showed stable disease; 3 patients (5%) had tumors which increased in size (2 being outside the radiosurgery treatment site). The actuarial freedom from progression rate (defined as further tumor growth) was thus 95%, with a median imaging follow-up of 26 months (range, 6-66 months). Although further follow-up is necessary, the results of this series clearly demonstrate that these lesions are feasible for treatment by modern radiosurgical techniques. Linac radiosurgery can stabilize skull base meningiomas, with decreased or unchanged tumor volumes on radiologic follow-up in approximately 95% of patients. Radiosurgery is a low-morbidity, effective technique as adjunct and sometimes primary treatment of small to moderate-sized meningiomas of the skull base.

Adult↗

PubMed1994

A multi-institutional experience with stereotactic radiosurgery for solitary brain metastasis.

PURPOSE: A multi-institutional experience in radiosurgery for solitary brain metastases was combined to identify factors associated with safety, efficacy, tumor control, and survival. MATERIALS AND METHODS: A review of 116 patients with solitary brain metastases who underwent gamma knife stereotactic radiosurgery at five institutions was performed. The median follow-up was 7 months following radiosurgery and 12 months following diagnosis. Minimum tumor doses varied from 8-30 Gy (mean, 17.5 Gy). Forty-five patients failed prior radiotherapy and 71 had no prior brain irradiation. Fifty-one patients had radiosurgery alone and 65 underwent combined radiosurgery with fractionated large-field radiotherapy (mean dose, 33.8 Gy). RESULTS: Median survival was 11 months after radiosurgery and 20 months after diagnosis. Follow-up documented local tumor control in 99 patients (85%), tumor recurrence in 17 (15%), and documented radiation necrosis in one (1%). The 2-year actuarial tumor control rate was 67 +/- 8%. Tumor histology affected survival (better for breast cancer, p = .004) and local control (better for melanoma and renal cell, p = .0003) in multivariate analyses. Combined fractionated radiotherapy and radiosurgery improved local control (p = 0.111), but not survival in multivariate testing. CONCLUSION: Radiosurgery is effective in controlling solitary brain metastases with low morbidity. Further study is needed to better define optimum treatment parameters for radiosurgery.

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