Enmin Wang

Pituitary Adenomas: The Effect of Gamma Knife Radiosurgery on Tumor Growth and Endocrinopathies

Seventy-three patients have been treated with Gamma Knife radiosurgery (GKR) for pituitary adenomas. 12 had undergone surgery prior to GKR. Three had had previous radiation therapy. The prescription dose administered to the tumor margin ranged from 9 to 35 Gy. 65 patients were followed up for an average of 29 months. A slight expansion of tumor volume occurred in 3 cases. Otherwise, the tumor volume remained unchanged or decreased in the remainder. Endocrine changes were present in all except 3 cases. GKR was followed by a speedy decrease in raised serum hormone levels in the case of both growth hormone (GH)and adrenocortico-tropic hormone (ACTH). In 3 patients there was some visual deterioration associated with a slight increase in tumor volume. In 2 cases, the tumors were removed surgically. Some preliminary conclusions may be drawn. The dose required to correct an endocrinopathy may be higher than that required for control of tumor growth. The recommended prescription dose for endocrine-active adenomas may be more than 30 Gy. While clinical improvement may be noted in patients with raised serum prolactin levels (PRL), normalization of the endocrinopathy may be less readily achieved than in the case of raised GH and ACTH levels. Gamma Knife radiosurgery as a primary treatment of pituitary adenomas can be safe and effective.

Long-term results of Leksell gamma knife surgery for trigeminal schwannomas

OBJECT The authors evaluated the long-term efficacy of gamma knife surgery (GKS) in patients with trigeminal schwannomas. METHODS Fifty-six patients, 31 women and 25 men (mean age 42 years), underwent GKS for trigeminal schwannomas. Fourteen had previously undergone surgery, and GKS was the primary treatment in the remaining 42 patients. The mean target volume was 8.7 cm3 (range 0.8-33 cm3); the mean maximum dose was 27 Gy (range 20-40 Gy); the mean tumor margin dose was 13.3 Gy (range 10-15 Gy); and the mean follow-up period was 68 months (range 27-114 months). Disappearance of the tumor occurred in seven patients. An obvious decrease in tumor volume was observed in 41 patients, four tumors remained unchanged, and four tumors progressed at 5, 26, 30, and 60 months, respectively. One patient with disease progression died of tumor progression at 36 months after GKS. The tumor growth control rate in this group was 93% (52 of 56 cases). Mild numbness or diplopia was relieved completely in 14 patients. Improvement of other neurological deficits was demonstrated in 25 patients. Trigeminal nerve dysfunction was either unchanged or slightly worse in 13 patients after GKS. Four patients experienced mild symptom deterioration related to tumor progression. CONCLUSIONS Radiosurgery proved to be an effective treatment for small- and medium-sized trigeminal schwannomas. Some larger tumors are also suitable for radiosurgery if there is no significant brainstem compression.

The long-term results of gamma knife radiosurgery for hemangioblastomas of the brain

OBJECT The authors assessed the long-term result of gamma knife surgery (GKS) for hemangioblastomas of the brain (HABs) and show histopathological findings after GKS. METHODS Thirty-five patients, 28 men and seven women, with a mean age of 36 years underwent GKS. Eighteen patients presented with multiple tumors and 17 with a solitary tumor. Twenty-one patients had von Hippel-Lindau (VHL) disease. The mean tumor diameter was 13 mm (range 5-55 mm). The mean follow up after GKS was 66 months (range 24-114 months). The mean prescription dose was 17.2 Gy (range 12-24 Gy) at the tumor margin. For tumors close to or within the brainstem a prescription dose of 12 to 13 Gy was used. At the most recent follow up, 29 patients were alive, six were dead, and satisfactory tumor control had been achieved in 29. A stable or improved neurological status was obtained in 21 patients. Eight patients underwent open surgery because of tumor-associated cyst enlargement or the development of new tumors after GKS. Seven patients developed new tumors and five of them required a second GKS. The 1-year tumor control rate was 94%; 2 years, 85%; 3 years, 82%; 4 years, 79%; and 5 years, 71%. Histopathology showed that no tumor cells were found and there was degeneration and necrosis in a tumor nodule 48 months after GKS with a prescription dose of 18 Gy. CONCLUSIONS Gamma knife surgery was a useful choice for small- or medium-sized, solid HAB in the long term, especially when the tumor margin dose was 18 Gy. Although GKS can treat multiple tumors in a single session, for HABs associated with VHL disease, GKS faces the dual problems of tumor recurrence or development of a new tumor.

Gamma Knife Radiosurgery as a Primary Surgical Treatment for Hypersecreting Pituitary Adenomas

Object: To estimate the efficacy of Gamma Knife radiosurgery (GKR) especially as a primary surgical treatment for hypersecreting pituitary adenomas. Methods: 274 patients were treated with GKR. The mean tumor volume was 1.86 cm3. The mean peripheral dose was 28.7 Gy. Results: 223 patients were followed up for an average of 31.6 months. The dose related to the tumor growth control and endocrinological normalization was detailed and statistical analysis of the data was performed. Conclusion: GKR as a primary surgical treatment for hypersecreting pituitary adenomas may be safe and effective.

Reversal of cerebral radiation necrosis with bevacizumab treatment in 17 Chinese patients

BackgroundBevacizumab has been suggested as a new treatment modality for cerebral radiation necrosis due to its ability to block the effects of vascular endothelial growth factor (VEGF) in leakage-prone capillaries, though its use still remains controversial in clinical practice.MethodsThe use of bevacizumab in 17 patients with symptomatic cerebral radiation necrosis poorly controlled with dexamethasone steroid treatments was examined between March 2010 and January 2012. Bevacizumab therapy was administered for a minimum of two cycles (7.5 mg/kg, at two-week interval) with a median of four bevacizumab injections. Changes in bi-dimensional measurements of the largest radiation necrosis lesions were observed by gadolinium-enhanced and T2-weighted magnetic resonance imaging (MRI). Additionally, dexamethasone dosage, Karnofsky performance status (KPS), adverse event occurrence and associated clinical outcomes were recorded for each patient.ResultsMRI analysis revealed that the average reduction was 54.9% and 48.4% in post-gadolinium and T2-weighted sequence analysis, respectively. Significant clinical neurological improvements were expressed in 10 patients according to KPS values. Dexamethasone reduction was achieved four weeks after initiation of bevacizumab in all patients, with four patients successfully discontinuing dexamethasone treatment. Mild to moderate bevacizumab-related adverse events, such as fatigue, proteinuria and hypertension were observed in three patients. Upon follow-up at 4 to 12 months, 10 patients showed clinical improvement, and 7 patient deaths occurred from tumor progression (5 patients), recurrent necrosis (1 patient), and uncontrolled necrosis-induced edema (1 patient).ConclusionsThese findings suggest bevacizumab as a promising treatment for cerebral radiation necrosis induced by common radiation therapies, including external beam radiotherapy (EBRT), stereotactic radiosurgery (SRS), and fractionated stereotactic radiotherapy (FSRT).

Phase II study to assess the efficacy of hypofractionated stereotactic radiotherapy in patients with large cavernous sinus hemangiomas.

PURPOSE Cavernous sinus hemangioma is a rare vascular tumor. The direct microsurgical approach usually results in massive hemorrhage. Although radiosurgery plays an important role in managing cavernous sinus hemangiomas as a treatment alternative to microsurgery, the potential for increased toxicity with single-session treatment of large tumors is a concern. The purpose of this study was to assess the efficacy of hypofractionated stereotactic radiotherapy in patients with large cavernous sinus hemangiomas. METHODS Fourteen patients with large (volume >20 cm(3)) cavernous sinus hemangiomas were enrolled in a prospective Phase II study between December 2007 and December 2010. The hypofractionated stereotactic radiotherapy dose was 21 Gy delivered in 3 fractions. RESULTS After a mean follow-up of 15 months (range, 6-36 months), the magnetic resonance images showed a mean of 77% tumor volume reduction (range, 44-99%). Among the 6 patients with cranial nerve impairments before hypofractionated stereotactic radiotherapy, 1 achieved symptomatic complete resolution and 5 had improvement. No radiotherapy-related complications were observed during follow-up. CONCLUSION Our current experience, though preliminary, substantiates the role of hypofractionated stereotactic radiotherapy for large cavernous sinus hemangiomas. Although a longer and more extensive follow-up is needed, hypofractionated stereotactic radiotherapy of 21 Gy delivered in 3 fractions is effective in reducing the tumor volume without causing any new deficits and can be considered as a treatment modality for large cavernous sinus hemangiomas.

Hypofractionated stereotactic radiosurgery: a new treatment strategy for giant cavernous sinus hemangiomas

OBJECTIVE Cavernous sinus hemangiomas (CSHs) are rare benign vascular tumors that arise from the dural venous sinuses lateral to the sella. Stereotactic radiosurgery (SRS) has emerged as a principal alternative to microresection for small- and medium-sized CSHs. Resection is a reasonable option for large (3-4 cm in diameter) and giant (> 4 cm in diameter) CSHs. However, management of giant CSHs remains a challenge for neurosurgeons because of the high rates of morbidity and even death that stem from uncontrollable and massive hemorrhage during surgery. The authors report here the results of their study on the use of hypofractionated SRS (H-SRS) to treat giant CSH. METHODS Between January 2008 and April 2014, 31 patients with a giant CSH (tumor volume > 40 cm3, > 4 cm in diameter) treated using CyberKnife radiosurgery were enrolled in a cohort study. Clinical status and targeted reduction of tumor volume were evaluated by means of serial MRI. The diagnosis for 27 patients was determined on the basis of typical imaging features. In 4 patients, the diagnosis of CSH was confirmed histopathologically. The median CSH volume was 64.4 cm3 (range 40.9-145.3 cm3). Three or 4 sessions of CyberKnife radiosurgery were used with a prescription dose based on the intent to cover the entire tumor with a higher dose while ensuring dose limitation to the visual pathways and brainstem. The median marginal dose to the tumor was 21 Gy (range 19.5-21 Gy) in 3 fractions for 11 patients and 22 Gy (range 18-22 Gy) in 4 fractions for 20 patients. RESULTS The median duration of follow-up was 30 months (range 6-78 months) for all patients. Follow-up MRI scans revealed a median tumor volume reduction of 88.1% (62.3%-99.4%) at last examination compared with the pretreatment volume. Ten patients developed new or aggravated temporary headache and 5 experienced vomiting during the treatment; these acute symptoms were relieved completely after steroid administration. Among the 30 patients with symptoms observed before treatment, 19 achieved complete symptomatic remission, and 11 had partial remission. One patient reported seizures, which were controlled after antiepileptic drug administration. No radiation-induced neurological deficits or delayed complications were reported during the follow-up period. CONCLUSIONS Hypofractionated SRS was an effective and safe modality for treating giant CSH. Considering the risks involved with microsurgery, it is possible that H-SRS might be able to serve as a definitive primary treatment option for giant CSH.