M. Selch

Dedicated linear accelerator radiosurgery for trigeminal neuralgia: a single-center experience in 179 patients with varied dose prescriptions and treatment plans.

PURPOSEnDedicated linear accelerator radiosurgery (D-LINAC) has become an important treatment for trigeminal neuralgia (TN). Although the use of gamma knife continues to be established, few large series exist using D-LINAC. The authors describe their results, comparing the effects of varied target and dose regimens.nnnMETHODS AND MATERIALSnBetween August 1995 and January 2008, 179 patients were treated with D-LINAC radiosurgery. Ten patients (5.58%) had no clinical follow-up. The median age was 74.0 years (range, 32-90 years). A total of 39 patients had secondary or atypical pain, and 130 had idiopathic TN. Initially, 28 patients received doses between 70 and 85 Gy, with the 30% isodose line (IDL) touching the brainstem. Then, using 90 Gy, 82 consecutive patients were treated with a 30% IDL and 59 patients with a 50% IDL tangential to the pons.nnnRESULTSnOf 169 patients, 134 (79.3%) experienced significant relief at a mean of 28.8 months (range, 5-142 months). Average time to relief was 1.92 months (range, immediate to 6 months). A total of 31 patients (19.0%) had recurrent pain at 13.5 months. Of 87 patients with idiopathic TN without prior procedures, 79 (90.8%) had initial relief. Among 28 patients treated with 70 Gy and 30% IDL, 18 patients (64.3%) had significant relief, and 10 (35.7%) had numbness. Of the patients with 90 Gy and 30% IDL at the brainstem, 59 (79.0%) had significant relief and 48.9% had numbness. Among 59 consecutive patients with similar dose but the 50% isodoseline at the brainstem, 49 patients (88.0%) had excellent/good relief. Numbness, averaging 2.49 on a subjective scale of 1 to 5, was experienced by 49.7% of the patients,nnnCONCLUSIONSnIncreased radiation dose and volume of brainstem irradiation may improve clinical outcomes with the trade-off of trigeminal dysfunction. Further study of the implications of dose and target are needed to optimize outcomes and to minimize complications.

Application of Stereotactic Radiosurgery to the Head and Neck Region

Nasopharyngeal carcinoma recurrent following primary radiation therapy has been treated with surgery and reirradiation. Reirradiation is often limited by the tolerance of structures previously treated. Radiosurgery was used to boost the recurrent site while avoiding critical structures. Seven patients were evaluated for treatment. Three patients met requirements for treatment. The lesions invaded the parapharyngeal region, the base of skull, cavernous sinus, cranial nerves, or carotid artery. Treatment included a radiosurgery boost utilizing multiple isocenters, noncoplanar arcs, and arc weighting, to yield a plan conforming to the tumors while avoiding critical anatomical structures. The patients tolerated the procedure well with minor acute side effects. Follow-up included magnetic resonance imaging (MRI) and positron emission tomography (PET). Two lesions responded, and one had no significant change. One patient had a regional recurrence. Two patients had distance recurrence. Long term side effects include trismus, parotiditis, ear fullness, hemorrhage, and pain. Radiosurgery may improve the local control rate of such lesions, however, with the severe long term complications of single fraction radiosurgery in the head and neck region this procedure may be more beneficial if the treatment is fractionated.

Preliminary Novalis Experience in the Treatment of Skull Base Chordomas with StereotacticRadiosurgery and Stereotactic Radiotherapy

Purpose: The treatment of chordomas is challenging. The role of radiation therapy in addition to surgery is well established. Different techniques have been applied aiming to improve tumor local contr

Long-Term Follow-Up Using Linac Radiosurgery and Stereotactic Radiotherapy as a Minimally Invasive Treatment for Intracranial Meningiomas

Purpose: Report of technical aspects, results and strategies of stereotactic radiosurgery (SRS) and stereotactic radiation therapy (SRT) for treatment of intracranial meningiomas. Methods: A retrospective review of intracranial meningiomas treated at UCLA from May 1991 to July 2003 was performed with emphasis on technical aspects, radiological and clinical results. 161 patients with intracranial meningiomas treated by linear accelerator (Linac) stereotactic radiation were identified. There were 33 meningiomas in 32 patients with follow-up more than 48 months. Mean patient age was 57.2 years (range 19–87). There were 25 females and 7 males. 21 patients had surgical resection prior to radiosurgery. Stereotactic radiation was the primary treatment in 12 patients. Single dose radiation to 26 lesions and 7 were treated with fractionated technique. SRS dose prescribed to the periphery of the tumor ranged from 12 to 22 Gy (mean 15 Gy), SRT dose ranged from 23 to 54 Gy (mean 48 Gy). The prescription isodose ranged from 50 to 90% for the single dose group and from 85 to 90% for the fractionated treatments. Results: Follow-up was available for 32 patients treated between 48 and 125 months (mean 72.5). Tumor growth control was achieved in 30 benign meningiomas treated with SRS (92.3%) and in 7 benign meningiomas treated with SRT (100%). Worsening of previous neurological deficit was identified in 2 patients (7.9%) treated with SRS. No complications were found in SRT patients. Conclusion: Radiosurgery has been an alternative to surgical resection of selected intracranial meningiomas. Patients with tumors not amenable to either surgery or radiosurgery are now candidates for a less invasive technique than conventional radiotherapy. The need for total/subtotal surgical resection of these tumors is being challenged by superior imaging capabilities that allow for precise and effective stereotactic radiotherapy.