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Nicole Angela Terpolilli, Moritz Ueberschaer, Maximilian Niyazi, Christoph Hintschich, Rupert Egensperger, Alexander Muacevic, Niklas Thon, Jörg-Christian Tonn, and Christian Schichor

OBJECTIVE

In meningiomas involving the orbit and optic canal, surgery is the mainstay of therapy. However, radical resection is often limited to avoid functional damage, so multidisciplinary treatment concepts are implemented. Data on the timing and value of early postoperative radiotherapy (PORT) are scarce. This retrospective study analyzes outcomes in patients who underwent targeted resection alone or in combination with early PORT.

METHODS

Patients undergoing resection of orbit-associated WHO grade I meningiomas from January 1999 to December 2013 who presented to the authors’ department at least twice for follow-up were included. Clinical and radiological findings were analyzed retrospectively. Patients were stratified into two cohorts: follow-up with MRI scans at regular intervals, i.e., the watch and wait (W&W) group, and a PORT group receiving PORT within 6 months after surgery in addition to MRI follow-up. Patients in the W&W group were scheduled for treatment when tumor progression was detected by imaging.

RESULTS

One hundred twenty-two patients were included. The mean follow-up was 70 months. The most common symptoms at presentation were visual disturbances; 87.7% of patients received Simpson grade II–III targeted partial resection. Twenty-three patients received PORT, and 99 patients were regularly observed with MRI scans (W&W group). Tumor recurrence/progression occurred significantly later (76.3 vs 40.7 months) and less frequently in the PORT group (13%) than in the W&W group (46.5%). Cases of recurrence were diagnosed an average of 39 months after initial surgery in both groups. PORT patients demonstrated significantly less visual impairment at last follow-up.

CONCLUSIONS

These results indicate that receiving PORT early after targeted partial resection might help to postpone tumor recurrence and the need for additional treatment, while preserving or even improving visual outcome.

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Pantaleo Romanelli, Alexander Muacevic, and Salvatore Striano

✓ Radiosurgery plays an important role in the treatment of refractory seizures induced by hypothalamic hamartomas (HHs). These lesions, deeply located and surrounded by a delicate vascular and neuronal network, are often associated with catastrophic epilepsy leading to progressive cognitive and behavioral deterioration. Surgical approaches include microsurgical resection, endoscopic resection or disconnection, radiofrequency lesioning, and interstitial brachytherapy. Radiosurgery is an emerging treatment modality for HHs, which provides excellent seizure outcomes and no lasting complications to date.

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Pantaleo Romanelli, Berndt Wowra, and Alexander Muacevic

✓ Optic nerve sheath meningiomas (ONSMs) are benign lesions originating from the dural sheath of the optic nerve. Progressive growth can lead to gradual loss of vision and exophthalmos. Loss of vision following microsurgical resection is not uncommon, and although stereotactic fractionated radiotherapy can be a safe alternative to control tumor growth and preserve vision, it may also lead to complications. Frame-based stereotactic radiosurgery has only been rarely used because single-fraction high-dose treatments of intrinsic optic nerve lesions may induce unacceptably high toxicity. New frameless radiosurgery devices such as the robotic CyberKnife, an image-guided radiosurgery system, can provide the extremely tight conformality and submillimetric accuracy of frame-based systems combined with the possibility of delivering radiation in several sessions. In the present report the authors review the clinical presentation and management of ONSMs and describe their preliminary experience using multisession radiosurgery to treat these lesions.

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Alexander Muacevic, Michael Staehler, Christian Drexler, Berndt Wowra, Maximilian Reiser, and Joerg-Christian Tonn

Object

The authors describe the technical application of the Xsight Spine Tracking System, data pertaining to accuracy obtained during phantom testing, and the initial clinical feasibility of using this fiducial-free alignment system with the CyberKnife in spinal radiosurgery.

Methods

The Xsight integrates with the CyberKnife radiosurgery system to eliminate the need for implantation of radiographic markers or fiducials prior to spinal radiosurgery. It locates and tracks spinal lesions relative to spinal osseous landmarks. The authors performed 10 end-to-end tests of accuracy using an anthropomorphic head and cervical spine phantom. Xsight was also used in the treatment of 50 spinal lesions in 42 patients. Dose planning was based on 1.5-mm-thick computed tomography slices in which an inverse treatment planning technique was used.

All lesions could be treated using the fiducial-free tracking procedure. Phantom tests produced an overall mean targeting error of 0.52 ± 0.22 mm. The setup time for patient alignment averaged 6 minutes (range 2–45 minutes). The treatment doses varied from 12 to 25 Gy to the median prescription isodose of 65% (40 to 70%). The tumor volume ranged between 1.3 and 152.8 cm3The mean spinal cord volume receiving greater than 8 Gy was 0.69 ± 0.35 cm3No short-term adverse events were noted during the 1- to 7-month follow-up period. Axial and radicular pain was relieved in 14 of 15 patients treated for pain.

Conclusions

Fiducial-free tracking is a feasible, accurate, and reliable tool for radiosurgery of the entire spine. By eliminating the need for fiducial implantation, the Xsight system offers patients noninvasive radiosurgical intervention for intra- and paraspinal tumors.

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Berndt Wowra, Alexander Muacevic, Anja Jess-Hempen, John-Martin Hempel, Stefanie Müller-Schunk, and Jörg-Christian Tonn

Object. The purpose of the study was to define the therapeutic profile of outpatient gamma knife surgery (GKS) for vestibular schwannoma (VS) by using sequential tumor volumetry to quantify changes following treatment.

Methods. A total of 111 patients met the inclusion criteria. The median follow-up duration was 7 years (range 5–9.6 years). Thirty-seven patients (33%) had undergone surgery before GKS and 10 (9%) had neurofibromatosis Type 2 (NF2). The median VS volume was 1.6 cm3 (range 0.08–8.7 cm3).

The actuarial 6-year tumor control rate after a single GKS treatment was 95%. Tumor swelling was observed in 43 patients (38.7%). Recurrence was significantly associated with NF2 (p < 0.003) and the reduced dose (p < 0.03) delivered to these tumors. The incidence of facial nerve neuropathy was mainly determined by surgery prior to GKS (p < 0.0001). Facial nerve radiation toxicity was mild and transient. No permanent facial nerve toxicity was observed. Trigeminal neuropathy occurred in 13 patients, and this was correlated with the VS volume (p < 0.02). The median hearing loss was −10 dB (range + 20 dB to −70 dB). The risk of hearing loss was correlated with age and transient tumor swelling (p < 0.05) but not with dose parameters or NF2.

Conclusions. Outpatient GKS is feasible, effective, and safe. Its therapeutic profile compares favorably with that of microsurgery.

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Berndt Wowra, Michael Siebels, Alexander Muacevic, Friedrich Wilhelm Kreth, Andreas Mack, and Alfons Hofstetter

Object. The aim of this study was to evaluate the therapeutic profile of repeated gamma knife surgery (GKS) for renal cell carcinoma that has metastasized to the brain on multiple occasions.

Methods. Data from this study were culled from a single institution and cover a 6-year period of outpatient radiosurgery. A standard protocol for indication, dose planning, and follow up was established. In cases of distant or local recurrences, radiosurgery was undertaken repeatedly (up to six times in one individual). Seventy-five patients harboring 350 cerebral metastases were treated.

Relief from pretreatment neurological symptoms occurred in 72% of patients within a few days or a few weeks after the procedure. The actuarial local tumor control rate after the initial GKS was 95%. In patients free from relapse of intracranial metastases after repeated radiosurgery, long-term survival was 91% after 4 years; median survival was 11.1 ± 3.2 months after radiosurgery and 4.5 ± 1.1 years after diagnosis of the primary kidney cancer. Survival following radiosurgery was independent of patient age and sex, side of the renal cell carcinoma, pretreatment of the cerebrum by using radiotherapy or surgery, number of brain metastases and their synchronization with the primary renal cell carcinoma, and the frequency of radiosurgical procedures. In contrast, survival was dependent on the patient's clinical performance score and the extracranial tumor status. Tumor bleeding was observed in seven patients (9%) and late radiation toxicity (LRT) in 15 patients (20%). Treatment-related morbidity was moderate and mostly transient. Late radiation toxicity was encountered predominantly in long-term survivors.

Conclusions. Outpatient repeated radiosurgery is an effective and only minimally invasive treatment for multiple brain metastases from renal cell cancer and is recommended as being the method of choice to control intracranial disease, especially in selected patients with limited extracranial disease. Physicians dealing with such patients should be aware of the characteristic aspects of LRT.

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Alexander Muacevic, Friedrich W. Kreth, Gerhard A. Horstmann, Robert Schmid-Elsaesser, Berndt Wowra, Hans J. Steiger, and Hans J. Reulen

Object. The aim of this retrospective study was to compare treatment results of surgery plus whole-brain radiation therapy (WBRT) with gamma knife radiosurgery alone as the primary treatment for solitary cerebral metastases suitable for radiosurgical treatment.

Methods. Patients who had a single circumscribed tumor that was 3.5 cm or smaller in diameter were included. Treatment results were compared between microsurgery plus WBRT (52 patients, median tumor dose 50 Gy) and radiosurgery alone (56 patients, median prescribed tumor dose 22 Gy). In case of local/distant tumor recurrence in the radiosurgery group, additional radiosurgical treatment was administered in patients with stable systemic disease. Survival time was analyzed using the Kaplan—Meier method, and prognostic factors were obtained from the Cox model. The patient groups did not differ in terms of age, gender, pretreatment Karnofsky Performance Scale (KPS) score, duration of symptoms, tumor location, histological findings, status of the primary tumor, time to metastasis, and cause of death. Patients who suffered from larger lesions underwent surgery (p < 0.01). The 1-year survival rate (median survival) was 53% (68 weeks) in the surgical group and 43% (35 weeks) in the radiosurgical group (p = 0.19). The 1-year local tumor control rates after surgery and radiosurgery were 75% and 83%, respectively (p = 0.49), and the 1-year neurological death rates in these groups were 37% and 39% (p = 0.8). Shorter overall survival time in the radiosurgery group was related to higher systemic death rates. A pretreatment KPS score of less than 70 was a predictor of unfavorable survival. Perioperative morbidity and mortality rates were 7.7% and 1.6% in the resection group, and 8.9% and 1.2% in the radiosurgery group, respectively. Four patients presented with transient radiogenic complications after radiosurgery.

Conclusions. Radiosurgery alone can result in local tumor control rates as good as those for surgery plus WBRT in selected patients. Radiosurgery should not be routinely combined with radiotherapy.