Gamma Knife surgery for the treatment of patients with asymptomatic meningiomas

2013 ◽  
Vol 119 (2) ◽  
pp. 487-493 ◽  
Author(s):  
David J. Salvetti ◽  
Tara G. Nagaraja ◽  
Carl Levy ◽  
Zhiyaun Xu ◽  
Jason Sheehan
Keyword(s):  
Gamma Knife ◽  
Symptom Control ◽  
Progression Free Survival ◽  
Lesion Size ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Symptom Development ◽  
Retrospective Case ◽  
Radiation Induced

Object Increasingly, meningiomas are detected incidentally, prior to symptom development. While these lesions are traditionally managed conservatively until symptoms develop or lesion growth occurs, it is conceivable that patients at high risk for symptom development may benefit from earlier intervention prior to the appearance of symptoms. However, little research has been performed to determine whether Gamma Knife surgery (GKS) can alter the rate of symptom development in such patients. Methods A retrospective case study was performed by screening the University of Virginia GKS database for patients treated for asymptomatic meningiomas. From the patient's medical records, pertinent demographic and treatment information was obtained. Yearly follow-up MRI had been performed to assess tumor control and detect signs of radiation-induced injury. Clinical follow-up via neurological examination had been performed to assess symptom development. Results Forty-two patients, 33 females (78.6%) and 9 males (21.4%), with 42 asymptomatic meningiomas were included in the analysis. The median age at GKS was 53 years. The most common lesion location was the cerebral convexities (10 lesions [23.8%]), and the median lesion size was 4.0 ml. The median duration of imaging and clinical follow-ups was 59 and 76 months, respectively. During the follow-up period, 1 tumor (2.4%) increased in size, 2 patients (4.8%) demonstrated symptoms, and 1 patient (2.4%) exhibited possible signs of radiation-induced injury. Thus, actuarial tumor control rates were 100%, 95.7%, and 95.7% for 2, 5, and 10 years, respectively. Actuarial symptom control at 5 and 10 years was 97% and 93.1%, respectively. Overall progression-free survival was 91.1% and 77.8% at 5 and 10 years, respectively. Conclusions Compared with published rates of symptom development in patients with untreated meningiomas, results in this study indicated that patients with asymptomatic lesions may benefit from prophylactic radiosurgery prior to the appearance of symptoms. Additionally, GKS is a treatment option that offers low morbidity.

Gamma Knife surgery for large vestibular schwannomas: a single-center retrospective case-matched comparison assessing the effect of lesion size

2013 ◽  
Vol 119 (2) ◽  
pp. 463-471 ◽  
Author(s):  
Brian J. Williams ◽  
Zhiyuan Xu ◽  
David J. Salvetti ◽  
Ian T. McNeill ◽  
James Larner ◽  
...  
Keyword(s):  
Treatment Failure ◽  
Gamma Knife ◽  
Univariate Analysis ◽  
Progression Free Survival ◽  
Lesion Size ◽  
Gamma Knife Surgery ◽  
Vestibular Schwannomas ◽  
Maximum Diameter ◽  
Tumor Control ◽  
Retrospective Case

Object Gamma Knife surgery (GKS) is a safe and effective treatment for patients with small to moderately sized vestibular schwannomas (VSs). Reports of stereotactic radiosurgery for large VSs have demonstrated worse tumor control and preservation of neurological function. The authors endeavored to assess the effect of size of VSs treated using GKS. Methods This study was a retrospective comparison of 24 patients with large VSs (> 3 cm in maximum diameter) treated with GKS compared with 49 small VSs (≤ 3 cm) matched for age, sex, radiosurgical margin and maximal doses, length of follow-up, and indication. Results Actuarial tumor progression-free survival (PFS) for the large VS cohort was 95.2% and 81.8% at 3 and 5 years, respectively, compared with 97% and 90% for small VSs (p = 0.009). Overall clinical outcome was better in small VSs compared with large VSs (p < 0.001). Patients with small VSs presenting with House-Brackmann Grade I (good facial function) had better neurological outcomes compared with patients with large VSs (p = 0.003). Treatment failure occurred in 6 patients with large VSs; 3 each were treated with resection or repeat GKS. Treatment failure did not occur in the small VS group. Two patients in the large VS group required ventriculoperitoneal shunt placement. Univariate analysis did not identify any predictors of treatment failure among the large VS cohort. Conclusions Patients with large VSs treated using GKS had shorter PFS and worse clinical outcomes compared with age-, sex-, and indication-matched patients with small VSs. Nevertheless, GKS has efficacy for some patients with large VSs and represents a reasonable treatment option for selected patients.

scholarly journals Gamma Knife surgery for patients with jugular foramen schwannomas: a multiinstitutional retrospective study in Japan

2016 ◽  
Vol 125 (4) ◽  
pp. 822-831 ◽  
Author(s):  
Toshinori Hasegawa ◽  
Takenori Kato ◽  
Yoshihisa Kida ◽  
Ayaka Sasaki ◽  
Yoshiyasu Iwai ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Gamma Knife ◽  
Radiation Effects ◽  
Progression Free Survival ◽  
Jugular Foramen ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Lower Cranial Nerve ◽  
Good Tumor Control

OBJECTIVE This study aimed to explore the efficacy and safety of stereotactic radiosurgery in patients with jugular foramen schwannomas (JFSs). METHODS This study was a multiinstitutional retrospective analysis of 117 patients with JFSs who were treated with Gamma Knife surgery (GKS) at 18 medical centers of the Japan Leksell Gamma Knife Society. The median age of the patients was 53 years. Fifty-six patients underwent GKS as their initial treatment, while 61 patients had previously undergone resection. At the time of GKS, 46 patients (39%) had hoarseness, 45 (38%) had hearing disturbances, and 43 (36%) had swallowing disturbances. Eighty-five tumors (73%) were solid, and 32 (27%) had cystic components. The median tumor volume was 4.9 cm3, and the median prescription dose administered to the tumor margin was 12 Gy. Five patients were treated with fractionated GKS and maximum and marginal doses of 42 and 21 Gy, respectively, using a 3-fraction schedule. RESULTS The median follow-up period was 52 months. The last follow-up images showed partial remission in 62 patients (53%), stable tumors in 42 patients (36%), and tumor progression in 13 patients (11%). The actuarial 3- and 5-year progression-free survival (PFS) rates were 91% and 89%, respectively. The multivariate analysis showed that pre-GKS brainstem edema and dumbbell-shaped tumors significantly affected PFS. During the follow-up period, 20 patients (17%) developed some degree of symptomatic deterioration. This condition was transient in 12 (10%) of these patients and persistent in 8 patients (7%). The cause of the persistent deterioration was tumor progression in 4 patients (3%) and adverse radiation effects in 4 patients (3%), including 2 patients with hearing deterioration, 1 patient with swallowing disturbance, and 1 patient with hearing deterioration and hypoglossal nerve palsy. However, the preexisting hoarseness and swallowing disturbances improved in 66% and 63% of the patients, respectively. CONCLUSIONS GKS resulted in good tumor control in patients with either primary or residual JFSs. Although some patients experienced some degree of symptomatic deterioration after treatment, persistent adverse radiation effects were seen in only 3% of the entire series at the last follow-up. Lower cranial nerve deficits were extremely rare adverse radiation effects, and preexisting hoarseness and swallowing disturbances improved in two-thirds of patients. These results indicated that GKS was a safe and reasonable alternative to surgical resection in selected patients with JFSs.

scholarly journals Gamma Knife surgery for patients with facial nerve schwannomas: a multiinstitutional retrospective study in Japan

2016 ◽  
Vol 124 (2) ◽  
pp. 403-410 ◽  
Author(s):  
Toshinori Hasegawa ◽  
Takenori Kato ◽  
Yoshihisa Kida ◽  
Motohiro Hayashi ◽  
Takahiko Tsugawa ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Gamma Knife ◽  
Facial Palsy ◽  
Survival Rates ◽  
Progression Free Survival ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Effective Treatment Option ◽  
Safe Alternative

OBJECT The aim of this study was to explore the efficacy and safety of stereotactic radiosurgery for patients with facial nerve schwannomas (FNSs). METHODS This study was a multiinstitutional retrospective analysis of 42 patients with FNSs treated with Gamma Knife surgery (GKS) at 1 of 10 medical centers of the Japan Leksell Gamma Knife Society (JLGK1301). The median age of the patients was 50 years. Twenty-nine patients underwent GKS as the initial treatment, and 13 patients had previously undergone surgery. At the time of the GKS, 33 (79%) patients had some degree of facial palsy, and 21 (50%) did not retain serviceable hearing. Thirty-five (83%) tumors were solid, and 7 (17%) had cystic components. The median tumor volume was 2.5 cm3, and the median prescription dose to the tumor margin was 12 Gy. RESULTS The median follow-up period was 48 months. The last follow-up images showed partial remission in 23 patients and stable tumors in 19 patients. Only 1 patient experienced tumor progression at 60 months, but repeat GKS led to tumor shrinkage. The actuarial 3- and 5-year progression-free survival rates were 100% and 92%, respectively. During the follow-up period, 8 patients presented with newly developed or worsened preexisting facial palsy. The condition was transient in 3 of these patients. At the last clinical follow-up, facial nerve function improved in 8 (19%) patients, remained stable in 29 (69%), and worsened in 5 (12%; House-Brackmann Grade III in 4 patients, Grade IV in 1 patient). With respect to hearing function, 18 (90%) of 20 evaluated patients with a pure tone average of ≤ 50 dB before treatment retained serviceable hearing. CONCLUSIONS GKS is a safe and effective treatment option for patients with either primary or residual FNSs. All patients, including 1 patient who required repeat GKS, achieved good tumor control at the last follow-up. The incidence of newly developed or worsened preexisting facial palsy was 12% at the last clinical follow-up. In addition, the risk of hearing deterioration as an adverse effect of radiation was low. These results suggest that GKS is a safe alternative to resection.

Gamma Knife surgery for convexity, parasagittal, and falcine meningiomas

2011 ◽  
Vol 114 (5) ◽  
pp. 1392-1398 ◽  
Author(s):  
Toshinori Hasegawa ◽  
Yoshihisa Kida ◽  
Masayuki Yoshimoto ◽  
Hiroshi Iizuka ◽  
Dai Ishii ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Initial Treatment ◽  
Survival Rates ◽  
Progression Free Survival ◽  
Local Tumor Control ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Tumor Diameter ◽  
Primary Tumors ◽  
Radiation Induced

Object The aim of this study was to evaluate the outcomes in patients with convexity, parasagittal, or falcine meningiomas treated using Gamma Knife surgery (GKS) and to determine management strategy considering a risk of radiation-induced edema. Methods One hundred twelve patients who harbored 125 convexity, parasagittal, or falcine meningiomas were assessed. Forty-six patients underwent GKS as the initial treatment. The median tumor diameter was 25 mm, and median tumor volume was 8 cm3. The median maximum and margin doses were 30 and 16 Gy, respectively. Results The median follow-up period was 72 months. The actuarial 5- and 10-year progression-free survival rates were 78% and 55%, respectively. The actuarial 5- and 10-year local tumor control rates were 87% and 71%, respectively. Of 29 tumors that developed postradiosurgical edema, 7 were symptomatic. The actuarial symptomatic radiation-induced edema rate was 7%. The incidence of this complication was significantly higher in patients who underwent GKS as the initial treatment. Six of 46 patients for whom GKS was the initial treatment had preradiosurgical edema. Of these 6 patients, 4 developed severe panhemispheric edema after GKS (2 patients with parasagittal tumors, 1 with a falx tumor, and 1 with a convexity tumor). Conclusions Gamma Knife surgery is an effective treatment for convexity, parasagittal, and falcine meningiomas as the initial or adjuvant treatment. However, GKS should be restricted to small- to medium-sized tumors, particularly in patients with primary tumors, because radiation-induced edema is more common in convexity, parasagittal, and falcine meningiomas than skull base meningiomas.

Gamma Knife surgery for nonvestibular schwannomas: radiological and clinical outcomes

2012 ◽  
Vol 116 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Mohamed Elsharkawy ◽  
Zhiyuan Xu ◽  
David Schlesinger ◽  
Jason P. Sheehan
Keyword(s):  
Gamma Knife ◽  
Maximum Dose ◽  
Progression Free Survival ◽  
Neurofibromatosis Type ◽  
Jugular Foramen ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Effective Treatment Option ◽  
Presenting Symptoms

Object Most intracranial schwannomas arise from cranial nerve (CN) VIII. Stereotactic radiosurgery is a mainstay of treatment for vestibular schwannomas. Intracranial schwannomas arising from other CNs are much less common. We evaluate the efficacy of Gamma Knife surgery on nonvestibular schwannomas including trigeminal, hypoglossal, abducent, facial, trochlear, oculomotor, glossopharyngeal, and jugular foramen tumors. Methods Thirty-six patients with nonvestibular schwannomas were treated at the University of Virginia Gamma Knife center from 1989 to 2008. The median patient age was 48 years (mean 45.6 years, range 10–72 years). Schwannomas arose from the following CNs: CN III (in 1 patient), CN IV (in 1), CN V (in 25), CN VI (in 2), CN VII (in 1), CN IX (in 1), and CN XII (in 3). In 2 patients, tumors arose from the jugular foramen. The median tumor volume was 2.9 cm3 (mean 3.3 cm3, range 0.07–8.8 cm3). The median margin dose was 13.5 Gy (range 9.3–20 Gy); the median maximum dose was 30 Gy (range 21.7–50.0 Gy). Results The mean and median follow-up times of 36 patients were 54 and 37 months, respectively (range 2–180 months). At the last radiological follow-up, the tumor size had decreased in 20 patients, remained stable in 9 patients, and increased in 7 patients. The 2-year actuarial progression-free survival was 91%. Higher maximum dose was statistically related to tumor control (p = 0.027). Thirty-three patients had adequate clinical follow-up. Among them, 21 patients had improvement in their presenting symptoms, 8 patients were stable after treatment with no worsening of their presenting symptoms, 2 patients developed new symptoms, and 1 patient experienced symptom deterioration. Notably, 1 patient with neurofibromatosis Type 2 developed new symptoms that were unrelated to the tumor treated with Gamma Knife surgery. Conclusions Gamma Knife surgery is a reasonably effective treatment option for patients with nonvestibular schwannomas. Patients require careful follow-up for tumor progression and signs of neurological deterioration.

Radiosurgery for intracranial hemangiopericytomas: outcomes after initial and repeat Gamma Knife surgery

2010 ◽  
Vol 112 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Claire Olson ◽  
Chun-Po Yen ◽  
David Schlesinger ◽  
Jason Sheehan
Keyword(s):  
Survival Rate ◽  
Local Recurrence ◽  
Gamma Knife ◽  
Survival Rates ◽  
Progression Free Survival ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Free Survival ◽  
Fractionated Radiotherapy

Object Intracranial hemangiopericytoma is a rare CNS tumor that exhibits a high incidence of local recurrence and distant metastasis. The purpose of this study was to evaluate the role of Gamma Knife surgery (GKS) in the management of intracranial hemangiopericytomas. Methods In a review of the University of Virginia radiosurgery database between 1989 and 2008, the authors found recurrent or residual hemangiopericytomas after resection in 21 patients in whom radiosurgery was performed to treat 28 discrete tumors. The median age of this population was 47 years (range 31–61 years) at the time of the initial GKS. Prior treatments included embolization (6), transcranial resection (39), transsphenoidal resection (2), and fractionated radiotherapy (8). The mean prescription and maximum radiosurgical doses to the tumors were 17.0 and 40.3 Gy, respectively. Repeat radiosurgery was used to treat 13 tumors. The median follow-up period was 68 months (range 2–138 months). Results At last follow-up, local tumor control was demonstrated in 47.6% of the patients (10 of 21 patients) with hemangiopericytomas. Of the 28 tumors treated, 8 decreased in size on follow-up imaging (28.6%), 5 remained unchanged (17.9%), and 15 ultimately progressed (53.6%). The progression-free survival rates were 90, 60.3, and 28.7% at 1, 3, and 5 years after initial GKS. The progression-free survival rate improved to 95, 71.5, and 71.5% at 1, 3, and 5 years after multiple GKS treatments. The 5-year survival rate after radiosurgery was 81%. Prior fractionated irradiation or radiosurgical prescription dose did not correlate with tumor control. In 4 (19%) of 21 patients extracranial metastases developed. Conclusions Radiosurgery is a reasonable treatment option for recurrent hemangiopericytomas. Long-term close clinical and imaging follow-up is necessary because of the high probability of local recurrence and distant metastases. Repeat radiosurgery may be used to treat new or recurrent hemangiopericytomas over a long follow-up course.

Gamma Knife surgery for parasellar meningiomas: long-term results including complications, predictive factors, and progression-free survival

2011 ◽  
Vol 114 (6) ◽  
pp. 1571-1577 ◽  
Author(s):  
Brian J. Williams ◽  
Chun Po Yen ◽  
Robert M. Starke ◽  
Bhuvaneswara Basina ◽  
James Nguyen ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Cranial Nerve ◽  
Tumor Volume ◽  
Progression Free Survival ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Free Survival ◽  
Factors Associated ◽  
The Mean

Object Stereotactic radiosurgery serves as an important primary and adjuvant treatment option for patients with many types of intracranial meningiomas. This is particularly true for patients with parasellar meningiomas. In this study, the authors evaluated the outcomes of Gamma Knife surgery (GKS) used to treat parasellar meningiomas. Methods The study is a retrospective review of the outcomes in 138 patients with meningiomas treated at the University of Virginia from 1989 to 2006; all patients had a minimum follow-up of 24 months. There were 31 men and 107 women whose mean age was 54 years (range 19–85 years). Eighty-four patients had previously undergone resection. The mean pre-GKS tumor volume was 7.5 ml (range 0.2–54.8 ml). Clinical and radiographic evaluations were performed, and factors related to favorable outcomes in each case were assessed. Results The mean follow-up duration was 84 months (median 75.5 months, range 24–216 months). In 118 patients (86%), the tumor volume was unchanged or had decreased at last follow-up. Kaplan-Meier analysis demonstrated radiographic progression-free survival at 5 and 10 years to be 95.4% and 69%, respectively. Fourteen patients (10%) developed new cranial nerve palsies following GKS. Factors associated with tumor control included younger age, a higher isodose, and smaller tumor volume. A longer follow-up duration was associated with either a decrease or increase in tumor volume. Fourteen patients (10%) experienced new or worsening cranial nerve deficits after treatment. Factors associated with this occurrence were larger pretreatment tumor volume, lower peripheral radiation dose, lower maximum dose, tumor progression, and longer follow-up. Conclusions Gamma Knife surgery offers an acceptable rate of tumor control for parasellar meningiomas and accomplishes this with a low incidence of neurological deficits. Radiological control after radiosurgery is more likely in those patients with a smaller tumor volume and a higher prescription dose.

Gamma Knife surgery for invasive pituitary macroadenoma

2006 ◽  
Vol 105 (Supplement) ◽  
pp. 26-30 ◽  
Author(s):  
Mooseong Kim ◽  
Sunghwa Paeng ◽  
Seyoung Pyo ◽  
Yeonggyun Jeong ◽  
Sunil Lee ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Cavernous Sinus ◽  
Pituitary Adenomas ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Pituitary Macroadenoma ◽  
Female Ratio ◽  
Fractionated Radiotherapy ◽  
The Mean

ObjectPituitary adenomas have been treated using a variety of modalities including resection, medication, fractionated radiotherapy, and stereotactic radiosurgery. The policy has been that all adenomas should first be treated with resection to reduce the volume of the tumor. The authors' study was conducted to determine the efficacy of using Gamma Knife surgery (GKS) for pituitary adenomas invading the cavernous sinus.MethodsOf 397 patients with pituitary tumors who underwent GKS between October 1994 and October 2005, 68 patients had pituitary macroadenomas invading the cavernous sinus. Sixty-seven cases were available for follow up. The mean age of the patients in these cases was 42.8 years (range 14–73 years). The male/female ratio was 0.8:1. The mean adenoma volume was 9.3 cm3. A total of 24 patients had undergone craniotomies and resection, and 11 patients had undergone transsphenoidal surgery prior to GKS. The mean follow-up period was 32.8 months. Tumor control was defined as a decrease or no change in tumor volume after GKS. Endocrinological improvement was defined as a decline in hormone levels to below 50% of the pre-GKS level.Tumor control was achieved in 95.5% of the cases. Endocrinological improvement was achieved in 68% of 25 patients. One patient suffered hypopituitarism after GKS.Conclusions Gamma Knife surgery is a safe and effective treatment for invasive pituitary macroadenoma with few complications.

Gamma knife surgery for cavernous hemangiomas: an analysis of 125 patients

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 81-86 ◽  
Author(s):  
Kang-Du Liu ◽  
Wen-Yuh Chung ◽  
Hsiu-Mei Wu ◽  
Cheng-Ying Shiau ◽  
Ling-Wei Wang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Gamma Knife Surgery ◽  
Content Type ◽  
Cavernous Hemangiomas ◽  
Rebleeding Rate ◽  
Radiation Induced ◽  
Bleeding Episodes ◽  
The Mean ◽  
Fine Print

Object. The authors sought to determine the value of gamma knife surgery (GKS) in the treatment of cavernous hemangiomas (CHs). Methods. Between 1993 and 2002, a total of 125 patients with symptomatic CHs were treated with GKS. Ninety-seven patients presented with bleeding and 45 of these had at least two bleeding episodes. Thirteen patients presented with seizures combined with hemorrhage, and 15 patients presented with seizures alone. The mean margin dose of radiation was 12.1 Gy and the mean follow-up time was 5.4 years. In the 112 patients who had bled the number of rebleeds after GKS was 32. These rebleeds were defined both clinically and based on magnetic resonance imaging for an annual rebleeding rate of 32 episodes/492 patient-years or 6.5%. Twenty-three of the 32 rebleeding episodes occurred within 2 years after GKS. Nine episodes occurred after 2 years; thus, the annual rebleeding rate after GKS was 10.3% for the first 2 years and 3.3% thereafter (p = 0.0038). In the 45 patients with at least two bleeding episodes before GKS, the rebleeding rate dropped from 29.2% (55 episodes/188 patient-years) before treatment to 5% (10 episodes/197 patient-years) after treatment (p < 0.0001). Among the 28 patients who presented with seizures, 15 (53%) had good outcomes (Engel Grades I and II). In this study of 125 patients, symptomatic radiation-induced complications developed in only three patients. Conclusions. Gamma knife surgery can effectively reduce the rebleeding rate after the first symptomatic hemorrhage in patients with CH. In addition, GKS may be useful in reducing the severity of seizures in patients with CH.

Gamma Knife surgery for Cushing's disease

2007 ◽  
Vol 106 (6) ◽  
pp. 980-987 ◽  
Author(s):  
Jay Jagannathan ◽  
Jason P. Sheehan ◽  
Nader Pouratian ◽  
Edward R. Laws ◽  
Ladislau Steiner ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Cushing’S Disease ◽  
Pituitary Adenomas ◽  
Cranial Nerve ◽  
Gamma Knife Surgery ◽  
Cushing's Disease ◽  
Free Cortisol ◽  
Radiation Induced ◽  
The Mean

Object In this study the authors address the efficacy and safety of Gamma Knife surgery (GKS) in patients with adrenocorticotropic hormone–secreting pituitary adenomas. Methods A review of data collected from a prospective GKS database between January 1990 and March 2005 was performed in patients with Cushing's disease. All but one patient underwent resection for a pituitary tumor, without achieving remission. Successful endocrine outcome after GKS was defined as a normal 24-hour urinary free cortisol (UFC) concentration posttreatment after a minimum of 1 year of follow up. Patient records were also evaluated for changes in tumor volume, development of new hormone deficiencies, visual acuity, cranial nerve neuropathies, and radiation-induced imaging changes. Ninety evaluable patients had undergone GKS, with a mean endocrine follow-up duration of 45 months (range 12–132 months). The mean dose to the tumor margin was 23 Gy (median 25 Gy). Normal 24-hour UFC levels were achieved in 49 patients (54%), with an average time of 13 months after treatment (range 2–67 months). In the 49 patients in whom a tumor was visible on the planning magnetic resonance (MR) image, a decrease in tumor size occurred in 39 (80%), in seven patients there was no change in size, and tumor growth occurred in three patients. Ten patients (20%) experienced a relapse of Cushing's disease after initial remission; the mean time to recurrence was 27 months (range 6–60 months). Seven of these patients underwent repeated GKS, with three patients achieving a second remission. New hormone deficiencies developed in 20 patients (22%), with hypothyroidism being the most common endocrinopathy after GKS. Five patients experienced new visual deficits or third, fourth, or sixth cranial nerve deficits; two of these patients had undergone prior conventional fractionated radiation therapy, and four of them had received previous GKS. Radiation-induced changes were observed on MR images in three patients; one had symptoms attributable to these changes. Conclusions Gamma Knife surgery is an effective treatment for persistent Cushing's disease. Adenomas with cavernous sinus invasion that are not amenable to resection are treatable with the Gamma Knife. A second GKS treatment appears to increase the risk of cranial nerve damage. These results demonstrate the value of combining two neurosurgical treatment modalities—microsurgical resection and GKS—in the management of pituitary adenomas.

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