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Yoshihisa Kida, Masayuki Yoshimoto and Toshinori Hasegawa

Object

The aim of this study was to evaluate the results of radiosurgery in patients with facial schwannoma.

Methods

The study population consisted of 14 patients, six men and eight women, with a mean age of 45.4 years. Most of the patients had presented with facial palsy (11 of 14 patients) and/or hearing disturbance (nine of 14 patients). Prior treatment in nine of the 14 cases consisted of tumor resection or tumor biopsy. Tumor volume ranged from 0.98 to 20.8 cm3, and the mean tumor volume was 5.5 cm3. The mean maximum radiation dose and mean tumor margin dose used for radiosurgery were 24.0 and 12.9 Gy, respectively.

During the mean follow-up period of 31.4 months (range 12–120 months), 10 of the tumors shrank and four remained unchanged. The tumor response and tumor control rates were 57 and 100%, respectively. None of the tumors progressed, and no subsequent resection was required. Facial nerve function improved in five cases, remained unchanged in eight, and became worse in one. There was no change in hearing function in any of the patients. Complications developed in only one patient: the onset of facial palsy immediately after treatment, which subsequently recovered to House–Brackmann Grade III.

Conclusions

In summary, radiosurgery was found to be a very useful method of treating facial schwannoma, for both tumor control and functional control. Radiosurgery should therefore be the treatment of first choice for facial schwannomas.

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Tatsuya Kobayashi, Yoshihisa Kida and Toshinori Hasegawa

Object

One hundred seven cases of craniopharyngiomas were treated using gamma knife surgery (GKS) at Komaki City Hospital during the past 12 years. The authors report the long-term results obtained in 100 patients who were followed for 6 to 148 months (mean 65.5 months).

Methods

All patients underwent GKS. The mean tumor diameter and volume were 18.8 mm and 5.8 ml, respectively; lesions were treated with a maximum dose of 21.8 Gy and marginal dose of 11.5 Gy (mean isocenters 4.5). Overall tumor responses were complete in 19, partial in 44, no change in 14, and disease progression in 23, yielding a complete response rate of 19%, overall response rate of 63%, control rate of 77%, and progression rate of 23%. Considering factors such as patient age, nature of the tumor (solid, mixed, cystic), frequency of previous treatments, and tumor size, the age and nature of the tumor were significant prognostic factors.

Changes in neurological and pituitary–hypothalamic symptoms after GKS were evaluated in 91 patients. Overall improvement was demonstrated in 17 (18.7%), no change in 59 (64.8%), and deterioration in 15 (16.5%). Outcome was documented in 93 cases: excellent in 42, good in 23, fair in seven, poor in three, and dead in 18 patients.

Conclusions

Stereotactic GKS is a safe and effective treatment as an adjuvant or boost therapy for postresection residual and/or recurrent craniopharyngiomas; the effects are durable and side effects acceptable.

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Yoshihisa Kida, Tatsuya Kobayashi and Yoshimasa Mori

Object. The purpose of this paper is to report the long-term results of gamma knife radiosurgery (GKS) for low-grade astrocytomas.

Methods. Fifty-one patients with low-grade astrocytomas treated with GKS and followed for more than 24 months are reported. Of the 51 patients, 12 harbored Grade I astrocytomas in and around the visual pathways and hypothalamus. The remaining 39 harbored Grade II astrocytomas. The mean patient age at time of GKS was 9.8 years for patient with Grade I and 30.9 years for those with Grade II astrocytomas. The mean tumor diameter was 25.4 mm for Grade I and 23.7 mm for Grade II tumors. The mean margin dose was 12.5 Gy for Grade I and 15.7 Gy for Grade II tumors.

In the mean follow-up period of 27.6 months, both Grade I and Grade II astrocytomas responded well to GKS. Grade I astrocytomas had a response rate of 50% and a control rate of 91.7%. Grade II astrocytomas had a 46.2% response rate and an 87.2% control rate. Statistical analyses concerning the efficacy and related factors showed a significantly better response for patients 10 years of age or older with Grade I and those with a follow-up period of more than 24 months. Complications included radiation-induced edema in 18 (35.3%) of 51 cases, cyst formation or enlargement in five (9.8%), and transient tumor enlargement in three (5.9%).

Conclusions. Radiosurgery can play an important role in the treatment of low-grade astrocytomas, and complete cure of these tumors is expected in at least some of the cases.

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Toshinori Hasegawa, Yoshihisa Kida, Masayuki Yoshimoto and Jouji Koike

Object

Information on outcomes of Gamma Knife surgery (GKS) for patients harboring trigeminal schwannomas is limited because these tumors are rare. The authors evaluated tumor control and functional outcomes in patients who underwent GKS for trigeminal schwannomas to clarify the efficacy of this treatment.

Methods

Forty-two patients with trigeminal schwannomas but no evidence of neurofibromatosis Type 2 were treated with GKS at Komaki City Hospital between November 1991 and December 2003. Of these, 37 patients were assessed. The mean tumor volume in these patients was 10 cm3. The mean maximum radiation dose directed to the tumor was 27.9 Gy and the mean dose directed to the tumor margin was 14.2 Gy. The mean follow-up period was 54 months. In four patients (11%) there was complete tumor remission; in 20 (54%) there was partial tumor remission; in eight (22%) the disease remained stable; and in five (14%) the tumor enlarged or uncontrollable facial pain developed with radiation-induced edema requiring resection. The actuarial 5- and 10-year tumor control rates were both 84%. With respect to functional outcomes, 40% of patients noted an improvement in their symptoms, and one patient experienced new symptoms despite good tumor control.

Conclusions

Gamma Knife surgery was a safe and effective treatment for a select group of patients harboring trigeminal schwannomas. Large tumors that compress the brainstem and cause deviation of the fourth ventricle should first be removed surgically and any remnant should be treated by GKS.

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Tatsuya Kobayashi, Yoshihisa Kida and Yoshimasa Mori

Object. The authors sought to analyze the long-term outcome of patients with Cushing disease who underwent gamma knife radiosurgery (GKS) as either an adjuvant or primary treatment.

Methods. Twenty-five patients with Cushing disease were treated by GKS and followed for more than 2.5 years (mean 5.3 years).

The overall results showed a complete response rate of 30%, a response rate of 85%, and a tumor control rate of 100%. Tumor size and radiation dose were the most important factors related to the treatment response. The complete response rate for microadenomas and small adenomas was significantly higher than that for macroadenomas. An 83.2% complete response rate was obtained using a maximum dose of more than 55 Gy and/or a margin dose of more than 40 Gy. Serum adrenocorticotropic hormone and cortisol levels were normalized in 35% of patients, decreased significantly in 60%, and decreased in 85%. Fifty-one of 85 characteristic signs and symptoms of Cushing disease improved without any side effects. The overall outcome was excellent in seven cases, good in six, fair in four, and poor in four cases; one patient died. The initial treatment was GKS in four patients, two of whom had a complete response and two of whom had a partial response. Hormone levels returned to normal in the patients in whom there was a complete response. The results in the six patients in whom Nelson syndrome was present were less favorable; the response rate was only 33%, although the control rate was 100%. Hormone levels decreased in two patients.

Conclusions. Gamma knife radiosurgery is safe and effective for the treatment of Cushing disease as an adjuvant or initial therapy when selective and accurate dose planning is performed.

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Tatsuya Kobayashi, Yoshihisa Kida, Yoshimasa Mori and Toshinori Hasegawa

Object

The authors analyzed the long-term outcomes of gamma knife surgery (GKS) for residual or recurrent craniopharyngiomas after microsurgery and the effects of dose reduction.

Methods

A total of 107 patients with craniopharyngiomas were treated with GKS at Komaki City Hospital during the past 12 years, and 98 patients were followed up for 6 to 148 months (mean 65.5 months). The mean tumor diameter and volume were 18.8 mm and 3.5 ml, respectively. These tumors were treated with a maximal dose of 21.8 Gy and a tumor margin dose of 11.5 Gy by using a mean of 4.5 isocenters. Final overall response rates were as follows: complete response 19.4%, partial response 67.4%, tumor control 79.6%, and tumor progression 20.4%. Reducing the tumor margin dose resulted in decreased therapeutic response and increased tumor progression, although the rate of visual and pituitary function loss also decreased. Among the factors examined, age (for adults) and the nature of the tumor (cystic or mixed) were statistically significant favorable and unfavorable prognostic factors, respectively. The actuarial 5- and 10-year survival rates were 94.1 and 91%, respectively. The progression-free survival rates were 60.8 and 53.8%, respectively. Patient outcomes were reportedly excellent in 45 cases, good in 23, fair in four, and poor in three; 16 patients died. Deterioration both in vision and endocrinological functions were documented as side effects in six patients (6.1%).

Conclusions

Stereotactic GKS is safe and effective, in the long term, as an adjuvant or boost therapy for residual or recurrent craniopharyngiomas after surgical removal and has minimal side effects. New treatment strategies must be devised to manage these tumors.

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Yoshihisa Kida, Tatsuya Kobayashi, Jun Yoshida, Kyouzou Kato and Naoki Kageyama

✓ Therapeutic results in 17 cases of alpha-fetoprotein (AFP)-secreting tumors of the central nervous system are reported. Twelve of the patients were male and five female. The patients' ages ranged from 5 years to 25 years (mean 13.6 years). The tumors originated in the pineal region in 10 cases, in the suprasellar region in four cases, and in both regions in one case; of the other two tumors, one originated in the basal ganglia and one in the sacrococcygeal region. Extraneural metastases or subarachnoid dissemination occurred in seven cases. Increased AFP titer in the serum or cerebrospinal fluid was verified in 13 cases. The patients were divided into two groups: those treated before (Group A) and those treated after (Group B) the introduction in 1980 of cisplatin as a chemotherapeutic agent. All seven Group A patients died, even after extensive therapy consisting of surgery, radiotherapy, and chemotherapy (ACNU or adriamycin) in some of the cases. The mean survival time following diagnosis for Group A was 23.7 months. Six of the 10 Group B patients died an average of 25.8 months after diagnosis; however, the other four were still alive and well an average of 25.3 months after diagnosis. The tumors responded well to chemotherapy consisting of cisplatin either alone or combined with bleomycin and vinblastine. The initial response rate to treatment in Group B was 100% and five cases had a complete remission, verified by computerized tomography or the serum AFP level. Once the tumor recurred, the response to cisplatin was markedly decreased. It is suggested that an effective therapy must still be sought for recurrent tumors.

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Toshinori Hasegawa, Yoshihisa Kida, Takenori Kato, Hiroshi Iizuka and Takashi Yamamoto

Object

Gamma Knife surgery (GKS) has been a safe and effective treatment for small- to medium-sized vestibular schwannomas (VSs) over relatively long-term outcomes. However, even with recent radiosurgical techniques, hearing results following GKS remain unsatisfactory. The purpose of this study was to evaluate the hearing preservation rate as well as factors related to hearing preservation in patients with VSs and serviceable hearing who were treated with GKS.

Methods

Among patients with Gardner-Robertson (GR) Class I or II serviceable hearing and VSs treated with GKS between 1991 and 2009, 117 were evaluable via periodic MR imaging and audiometry.

Results

The median age at the time of GKS was 52 years. Four patients (3%) had undergone prior surgery. Fifty-six patients (48%) had GR Class I hearing and 61 (52%) had GR Class II hearing at the time of GKS. The median tumor volume was 1.9 cm3. The median maximum and tumor margin radiation doses were 24 and 12 Gy, respectively. The median follow-up periods for MR imaging and audiometry were 74 and 38 months, respectively. The overall tumor control rate was 97.5%. Actuarial 3-, 5-, and 8-year hearing preservation rates were 55%, 43%, and 34%, respectively. On multivariate analysis, GR hearing class at the time of GKS and the mean cochlear dose affected hearing preservation significantly. In a limited number of patients who were treated using the most recent dose planning techniques and who had GR Class I hearing before treatment, the 3- and 5-year hearing preservation rates increased to 80% and 70%, respectively.

Conclusions

For the majority of patients with small- to medium-sized VSs, GKS was an effective and reasonable alternative to resection with satisfactory long-term tumor control. Factors related to hearing preservation included a GR Class I hearing pre-GKS and a lower mean cochlear radiation dose. To retain serviceable hearing, it is important to apply GKS treatment while patients retain GR Class I hearing.

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Tatsuya Kobayashi, Yoshimasa Mori, Yukio Uchiyama, Yoshihisa Kida and Shigeru Fujitani

Object. The authors conducted a study to determine the long-term results of gamma knife surgery for residual or recurrent growth hormine (GH)—producing pituitary adenomas and to compare the results with those after treatment of other pituitary adenomas.

Methods. The series consisted of 67 patients. The mean tumor diameter was 19.2 mm and volume was 5.4 cm3. The mean maximum dose was 35.3 Gy and the mean margin dose was 18.9 Gy. The mean follow-up duration was 63.3 months (range 13–142 months).

The tumor resolution rate was 2%, the response rate 68.3%, and the control rate 100%. Growth hormone normalization (GH < 1.0 ng/ml) was found in 4.8%, nearly normal (< 2.0 ng/ml) in 11.9%, significantly decreased (< 5.0 ng/ml) in 23.8%, decreased in 21.4%, unchanged in 21.4%, and increased in 16.7%. Serum insulin-like growth factor (IGF)—1 was significantly decreased (IGF-1 < 400 ng/ml) in 40.7%, decreased in 29.6%, unchanged in 18.5%, and increased in 11.1%, which was almost parallel to the GH changes.

Conclusions. Gamma knife surgery was effective and safe for the control of tumors; however, normalization of GH and IGF-1 secretion was difficult to achieve in cases with large tumors and low-dose radiation. Gamma knife radiosurgery is thus indicated for small tumors after surgery or medication therapy when a relatively high-dose radiation is required.