Clinical, radiological, and histopathological predictors for long-term prognosis after surgery for atypical meningiomas.

BACKGROUND: Despite considerable rates of recurrence and mortality in atypical meningiomas, reliable predictors for estimating postoperative long-term prognosis remain elusive. METHODS: Clinical, histopathological, and radiological variables from 138 patients, including 64 females and 74 males (46% and 54%, median age 62 years), who underwent surgery for intracranial atypical meningioma were retrospectively analyzed. Associations between variables and recurrence and mortality were investigated using uni- and multivariate analyses. RESULTS: Gross total (GTR) and subtotal resection (STR) was achieved in 81% and 19% of cases, respectively. Within a median follow-up of 62 months, recurrence occurred in 52 (38%) and mortality in 22 (16%) cases. In patients who did not receive adjuvant irradiation, recurrence rates were higher after STR than after GTR (32% vs 63%, p = 0.025). In univariate analyses, only intratumoral calcifications on preoperative MRI (p = 0.012) and the presence of brain invasion in the absence of other histological grading criteria (p = 0.010) were correlated with longer progression-free intervals (PFI). In multivariate analyses, patient age was positively (HR 1.03, 95%CI 1.04-1.05; p = 0.018) and the presence of brain invasion as the only grading criterion (HR 0.37, 95%CI 0.19-0.74; p = 0.005) was negatively related with progression, while rising age at the time of surgery (HR 1.07, 95%CI 1.03-1.12; p = 0.001) was prognostic for mortality. CONCLUSIONS: PFI was longer in brain invasive but otherwise histological benign meningiomas and in tumors displaying calcifications on preoperative MRI. Advancing patient age and lower Karnofsky Performance Score were associated with higher overall mortality.

Stereotactic radiosurgery of a papillary tumor of the pineal region: case report and review of the literature.

BACKGROUND/AIMS: Papillary tumors of the pineal region are a recently described very rare group of primary CNS neoplasms. Because of their rarity, it has proven to be difficult to establish the optimal therapy. Furthermore, microsurgical resection of pineal region neoplasms is associated with quite a high morbidity. We report the first case of stereotactic radiosurgery of a histologically confirmed papillary tumor of the pineal region. METHODS: After establishing the diagnosis by stereotactic biopsy, the patient was treated with stereotactic radiosurgery in a Gamma Knife unit. RESULTS: Five years after treatment, the tumor size is still decreasing, showing a good response to the treatment. CONCLUSIONS: Stereotactic radiosurgery should be considered a treatment option in these surgically challenging tumors.

A comparative study of microsurgery and gamma knife radiosurgery in vestibular schwannoma evaluating tumor control and functional outcome.

Background: Both stereotactic radiosurgery (SRS) and microsurgical resection (SURGERY) are available as treatment options for sporadic vestibular schwannoma (VS). There are very few direct comparative studies comparing both treatment modalities in large cohorts allowing detailed subgroup analysis. This present study aimed to compare the nuances in the treatment of VS by SURGERY and SRS in 2 highly specialized neurosurgical centers. Methods: This is a retrospective bicentric cohort study. Data from patients treated between 2005 and 2011 were collected retrospectively. Recurrence-free survival (RFS) was assessed radiographically by contrast-enhanced magnetic resonance imaging. Results: The study population included N = 901 patients with a mean follow-up of 7 years. Overall, the incidence of recurrence was 7% after SURGERY, and 11% after SRS with superior tumor control in SURGERY in the Kaplan-Meier-analysis (P = 0.031). In small tumors (Koos I and II), tumor control was equivalent in both treatment arms. In large VS (Koos III and IV), however, RFS was superior in SURGERY. The extent of resection correlated with RFS (P < .001). Facial and hearing deterioration was similar in both treatment arms in small VS, but more pronounced in SURGERY of large VS. Tinnitus, vertigo, imbalance, and trigeminal symptoms were more often improved by SURGERY than SRS. Conclusions: SRS can achieve similar tumor control compared to SURGERY in smaller VS (Koos I and II)-with similar postinterventional morbidities. In large VS (Koos III and IV), long-term tumor control of SRS is inferior to SURGERY. Based on these results, we suggest that if combination therapy is chosen, the residual tumor should not exceed the size of Koos II.

Local Tumor Control and Clinical Symptoms After Gamma Knife Radiosurgery for Residual and Recurrent Vestibular Schwannomas.

BACKGROUND: The use of Gamma Knife radiosurgery (GKRS) for recurrent or residual vestibular schwannoma (VS) after microsurgery (MS) has been investigated in several retrospective studies. The purpose of this study was to identify potential risk factors for both neurologic deterioration and tumor progression after GKRS for previously operated VSs in a prospective setting. METHODS: Patients who underwent GKRS for previously operated and histopathologically confirmed VS between 1998 and 2015 were prospectively followed-up. Risk factors for therapy side effects and predictors for tumor control were investigated in uni- and multivariate analyses. RESULTS: A total of 160 individuals with a median age of 55 years were included. Median tumor volume prior to GKRS was 1.40 cm3 (range, 0.06-35.80 cm3). After a median follow-up of 36 months, hearing and facial nerve function were serviceable (modified Gardner-Robertson and House-Brackmann grades I and II) in 7 (5%) and 82 (55%) patients, respectively. Deterioration to a nonserviceable facial nerve function after GKRS was found in 3% (3/89) and tended to increase with rising tumor volume (odds ratio, 1.65 per cm3; 95% confidence interval, 1.00-2.71; P = 0.051). Median tumor volume prior to GKRS was higher in patients with radiologic (P = 0.020) or clinical tumor progression (P < 0.001). Critical tumor volume prior to GKRS to predict clinical and radiologic tumor progression was 1.30 cm3 (P < 0.001) and 3.30 cm3 (P = 0.019), respectively. However, in multivariate analyses, none of the analyzed variables were found to independently predict tumor progression. CONCLUSIONS: Intended submaximal resection followed by GKRS is a viable treatment for VS. Because tumor remnant size after MS is an important predictor for recurrence after adjuvant GKRS, both brainstem and cerebellar decompression and maximal safely achievable resection should remain major goals of microsurgery.

Gamma Knife surgery for multiple brain metastases from a malignant schwannoma of the penis.

The occurrence of brain metastases from a malignant schwannoma of the penis is extremely rare. In patients with a single brain metastasis, microsurgical extirpation is the treatment of choice and verifies the diagnosis. In cases of multiple or recurrent metastases, radiosurgery is an effective and safe therapy option. Gamma Knife surgery was performed in a patient who had previously undergone tumor resection and who presented with recurrence of the lesion and three de novo brain metastases. This first report on brain metastasis from a malignant penile schwannoma illustrates the efficacy and safety of radiosurgical treatment for these tumors.

Increased preservation of functional hearing after gamma knife surgery for vestibular schwannoma.

OBJECT: Gamma knife surgery (GKS) for vestibular schwannoma is still associated with an additional hearing loss of approximately 30%. The purpose of this study was to record the effect on hearing preservation of maintaining a margin dose of 13 Gy while reducing the maximum dose to 20 Gy. METHODS: Seventy-eight of 95 patients who entered a prospective protocol with a follow up of at least 12 months (mean 22 months) were evaluated. The mean tumor volume was 2.28 cm3. After a mean follow-up duration of 22 months, the magnetic resonance imaging-based tumor control rate was 87%. In two cases a second procedure (surgery) was necessary. Thus, the clinical control rate was 97.5%. In two cases there was an increase in trigeminal dysesthesia. One patient suffered transient facial nerve impairment. Functional hearing was preserved in 83.4% of the patients with functional hearing preoperatively. CONCLUSIONS: Reducing the maximum dose to 20 Gy seems to be an effective treatment, which probably increases preservation of functional hearing without sacrificing the high tumor control rates achieved in radiosurgery. Postradiosurgery tumor swelling occurred in 25% of the cases and was not correlated with hearing deterioration.

Gamma knife model C with the automatic positioning system and its impact on the treatment of vestibular schwannomas.

OBJECT: The aim of this study was to assess the effects of the gamma knife automatic positioning system (APS) on the treatment of patients, particularly effects of this system on the treatment of patients with vestibular schwannomas (VSs), with a view to reducing loss of hearing. METHODS: The dose delivery with an increased number of shots was checked with GAFChromic Film for various numbers of shots (one to 129). The results in the first 549 patients were recorded. In addition a series of 59 patients with VSs treated with 13 Gy to the 65% isodose is presented. The authors have termed this the "13 on 65" concept. The film dosimetry showed that a large number of small shots did not materially affect the dose and dose distribution produced by gamma knife treatment. The APS was used alone in 72% of arteriovenous malformations, 71% of meningiomas, 94% of VSs, and 84% of pituitary adenomas. Metastatic tumors were accessible in a pure APS mode in 59% of all cases, glioma in 58%, and uveal melanoma in 10% of the cases. Thus two thirds of patients could be treated using APS alone. It was possible to use the APS and manual systems together for complex or very eccentrically placed targets. The APS resulted in the use of a larger number of isocenters. After a mean follow-up period of 15 months, the results in patients with the VSs in whom 13 Gy was delivered to the 65% isodose were similar to those in patients treated with the more conventional 50% margin isodose. There was no change in the incidence of hearing loss within the study period, and the incidence of trigeminal and facial neuropathies remained unchanged after treatment as well. CONCLUSIONS: The APS encourages the design of more conformal dose plans. The greater use of smaller collimators results in a steeper dose gradient with a smaller amount of radiation outside the target volume. Because the APS is able to apply a large number of smaller isocenters in an acceptable time, the number of isocenters used is increased. An increased number of isocenters can also be used to reduce the maximum radiation dose and increase the homogeneity in a given dose plan.

Gamma Knife radiosurgery following subtotal resection of vestibular schwannoma.

During treatment of large vestibular schwannomas, incomplete resection (IR) followed by Gamma Knife surgery (GKS; Elekta AB, Stockholm, Sweden) possibly offers tumor growth control and good clinical outcome, and is being discussed as an alternative to complete tumor removal with its inherent risks, especially for facial nerve function. However, available data for this concept are limited due to the small number of published studies. To analyze the effects of combined therapy in a larger cohort, we reviewed the currently available data. Six studies comprising 159 patients with a tumor diameter of at least 2 cm were included (median volume 19.95 cm(3) in four studies, n=137). GKS was performed on average 6 months postoperatively with a mean marginal dose of 11.88 Gy (mean target volume 4.42 cm(3), mean diameter 18.45 mm). Preoperatively facial nerve function was serviceable (House and Brackmann Grades I+II) in 158 of 159 patients (99.4%) and in 125 of 151 patients (82.8%, 95% confidence interval [CI] 76-88%) postoperatively. Hearing was serviceable in 29 of 151 patients (19.2%) preoperatively and in 16 of 79 patients postoperatively (20.2%, 95%CI 12-31%). Within a mean follow-up time of 50 months (range 12-102 months), facial nerve function and hearing after IR remained serviceable in 142 of 151 (94.0%, 95%CI 89-97%) and 15 of 129 patients (11.6%, 95%CI 7-18%). Tumor growth control was achieved in 149 of 159 patients (93.8%). Six patients were subjected to repeated therapy. Minimal complications were reported for microsurgery and GKS. Combined therapy was shown to be beneficial regarding both tumor control and adverse side effects among all analyzed studies.

Gamma Knife surgery for central neurocytomas.

OBJECT: The optimal management of central neurocytoma (CN) remnants and recurrences is still not clear. To date no large series of patients treated with Gamma Knife surgery (GKS) for CNs has been published. For that reason the authors decided to combine data from 5 different centers so that they could analyze the largest population of patients treated with GKS for CN currently available. METHODS: Data obtained in 42 patients who were treated for CN with GKS before July 1, 2010, were retrospectively collected and analyzed. The median prescribed dose was 13 Gy (range 11-25 Gy). The follow-up time in these patients ranged from 0.5 to 14.7 years (mean 6.1 years, median 4.9 years). Eleven patients were followed up for 5-10 years and 9 patients for more than 10 years. All patients were alive and well at the closing of the study except 1 patient, who died of injuries sustained in a traffic accident. RESULTS: Two cases of local tumor progression and 2 cases of distant tumor recurrence occurred among the patient population, yielding 5- and 10-year tumor control rates of 91% and 81%, respectively. No permanent complications occurred. The findings were in line with results reported in earlier publications. Despite the high tumor control rate, enlargement of part of or the whole ventricular system was seen in 45% of patients. CONCLUSIONS: The high tumor control rate and the low complication rate following GKS indicate that GKS is the preferred treatment for CN tumor remnants or recurrences following microsurgery. However, data from longer follow-up times in more patients are needed before this conclusion can be validated. The patients need to be closely monitored and potential hydrocephalus managed despite tumor control.