RediFoam Immobilization System Technique for Stereotactic Body Radiosurgery

Stereotactic radiosurgery had been developed in the early sixties in Sweden, and recently adapted at Karolinska Institute to treat the inoperable neoplasms of the chest, abdomen and pelvis. The new method uses a specially designed stereotactic body frame, which is a device equipped with feducial markers. The patient is positioned inside the body frame with the area of interest within the boundaries of the feducial markers. These allow for the localization of the tumor to be treated and the exact positioning of an isocenter, which is essential for the successful administration of multiple treatments. The method for patient repositioning as suggested by the Karolinska Hospital, Stockholm is the use of a vacuum bag, which although efficient in patient immobilization, has certain inherent risks. At Staten Island University Hospital we proposed to use a custom fitted rigid body mold. The material used is RediFoam Immobilization System, a two part MDI-based rigid urethane system. When the ingredients are properly mixed the chemical reaction results in a custom impression of the patients contours. Its rigid structure will not be altered by normal use thereby insuring patient immobilization and replication. The system allows to use a smaller number of SBF and provides substantial cost effectiveness.     

Radiosurgery for Tumors in the Body: Clinical Experience Using a New Method

A stereotactic body frame for exact tumor localization, reproducible fixation, and high-dose fraction irradiation with an accelerator (radiosurgery) has been developed. With the aid of this body frame, tumors are usually treated with five to nine static coplanar or noncoplanar beams yielding a planned inhomogeneous dose distribution with a 50% higher dose in the center of the tumor compared to the periphery of the planning target volume. Due to the steep dose gradient, the surrounding normal tissue is exposed to relatively low doses. Seventy-five evaluable tumors in 50 patients in whom conventional treatment modalities had been exhausted or considered inapplicable have been treated with doses of between 15 and 45 Gy (mean, 28 Gy) at the periphery of the planning target volume delivered in one to five fractions (mean, 2.5). The tumors, which had volumes ranging from 2–732 cm³ (mean, 73 cm³), were mainly metastases, from a variety of primaries, in the liver, lungs, and retroperitoneal space. Some primaries such as lung cancer and primary liver cancer were also treated. During an evaluation period of 1.5–38 months (mean, 11 months) 22 tumors showed growth arrest (29.3%), 29 were reduced in size (38.7%), and 24 disappeared (32%) as judged by computed tomography examinations, which were usually performed at 2- to 3-month intervals after radiosurgery. Four of the tumors were classified as local failures (5.3%). This treatment, which is noninvasive, painless, and rapid and does not require hospitalization, does not impair the quality of life of the patients when used properly. Treatment has been given regardless of age and medical status of the patients.     

Stereotactic Radiosurgery for Patients with Single Brain Metastasis

The efficacy of stereotactic radiosurgery (SRS) was evaluated for patients with single brain metastasis from extracranial primary cancer and the outcome was compared with that of external whole brain irradiation (WBI) alone or with surgical resection. Between January 1976 and December 1996, 225 patients with single brain metastases were treated in the Department of Therapeutic Radiology—Radiation Oncology at the University of Minnesota Hospital. One hundred six patients (47%) were treated with WBI alone (Group 1), 71 patients (32%) underwent surgical resection prior to WBI (Group 2), and 48 patients (21%) underwent SRS ± WBI (Group 3). The most common site of primary cancer was the lung (40%), followed by breast (14%), unknown primary (11%), skin (malignant melanoma, 9%), gastrointestinal tract (8%), kidney (renal cell carcinoma, 8%), gynecological organs (3%), and other (6%). Median dose to the whole brain was 3750 cGy in 15 fractions (range, 2000–5000 cGy). Median radiosurgical dose of 1750 cGy (range, 1200–4000 cGy) was delivered to the 40 to 90% isodose line encompassing the target. Actuarial survival was calculated from the date of treatment using the Kaplan–Meier method and statistical significance was assessed with the log-rank test. Actuarial median survival was 3.8 months for Group 1 (range, 1–84 months), 10.5 months for Group 2 (range, 1–125 months), and 9.8 months for Group 3 (range, 1–51 months). Survival at 1 and 2 years was 20% and 8% for Group 1, 47% and 18% for Group 2, and 37% and 27% for Group 3, respectively. Group 2 (surgery + WBI) and Group 3 (SRS ± WBI) had a statistically significant survival advantage over Group 1 (WBI alone) (p < 0.0001, log-rank test). No survival advantage was found between Groups 2 and 3 (p = 0.69, log-rank test). Our retrospective data suggest that SRS (± WBI) improves survival when compared to WBI alone and is comparable to surgical resection and WBI. Given that SRS is minimally invasive, is able to treat lesions in surgically inaccessible locations, and is potentially more cost-effective than surgery, it is a reasonable and potentially more attractive alternative to surgery in the management of single brain metastasis.     

Stereotactic Radiosurgery for Tonsillar Carcinoma

Background: Stereotactic radiosurgery (SRS) was developed for the treatment of patients with intracranial lesions; indeed, the stereotactic equipment is derived from neurosurgical tools. However, SRS may be feasible for any small lesions that can be targeted with Stereotactic apparatus. In this report we describe the use of SRS in treating a patient with a squamous cell cancer of the oropharynx. Methods: A 62-year-old man had received 65 Gray (Gy) postoperative radiation therapy for a floor of mouth cancer 3 years prior to this presentation. He had developed a second primary of his tonsil within the previous radiation portals. Because of a recent myocardial infarction he was unable to undergo salvage surgery or interstitial brachytherapy. He was unable to have intraoral cone electron beam treatment or contact brachytherapy because of severe trismus. He therefore underwent 30 Gy in 15 fractions of external beam radiation followed by a Stereotactic boost of 850 centigray (cGy) in one fraction. Results: The Stereotactic boost delivered a tumoricidal radiation dose while sparing the mandible and other vital structures. He tolerated the treatment well with a complete local tumor response. Conclusions: In selected patients, stereotactic radiosurgery is a viable option in the management of head and neck cancer.     

Stereotactic Radiosurgery for Tentorial Meningiomas

Summary Radical microsurgical resection is the procedure of choice for tentorial meningiomas. Despite advances in microsurgery, tentorial meningiomas continue to challenge surgeons and patients. To evaluate the response of tentorial meningiomas, we evaluated 41 patients who had Gamma knife stereotactic radiosurgery during a 9 year period. Patient age varied from 32 to 79 years. Headache, trigeminal neuralgia, or facial paraesthesia were the most common presenting symptoms. Sensory deficits in the distribution of the trigeminal nerve were the most common finding. Eighteen patients (44%) had undergone between 1 and 5 (mean, 1.9) resections prior to radiosurgery; 23 had tumors diagnosed by neuroimaging. The average tumor diameter in this series was 20 mm. The maximum tumor dose varied from 24 to 40 Gy (mean, 30.5 Gy), and the tumor margin dose varied from 12 to 20 Gy (mean, 15.3 Gy). During the average follow-up interval of 3 years (range, 1–8 years), 19 patients had clinical improvement, 20 remained stable, and 2 patients deteriorated. Follow-up imaging showed a reduction in tumor size in 18 patients, no further tumor growth in 22, and an increase in tumor size in one (overall tumor control rate of 98%). Stereotactic radiosurgery using the Gamma Knife was a safe and effective primary or adjuvant treatment for patients with tentorial meningiomas.     

Stereotactic Radiosurgery for Human Glioma: Treatment Parameters and Outcome for Low vs. High Grade

Stereotactic radiosurgery (SRS) offers the precise, local delivery of radiation for the treatment of recurrent gliomas. We examined the comparative characteristics, treatments, and outcome in a population having with low– and high–grade gliomas. Between September 1991 and December 1995, 20 patients (13 males, 7 females) had SRS for low-grade [9 patients: World Health Organization (WHO) grade II] vs. high-grade (11 patients: 9 WHO grade IV and 2 WHO grade III) gliomas. The patients with low-grade gliomas were younger (mean age ± SE, 39.6 ± 5.4 years; range, 11.4–61.0 years) than those with high-grade gliomas (51.3 ± 13.9 years; range, 32.9–78.5 years) (P = 0.09). Tumor locations were similar in the two groups: lobar for 7 of 9 low-grade vs. 9 of 11 high-grade gliomas (P = NS) and diencephalic or cerebellar for the remainder. The initial surgical treatments were biopsy, subtotal resection, and total resection for three, three, and three patients with low-grade gliomas, vs. three, seven, and one patients with high-grade gliomas, respectively (P = NS). Except for three patients with low-grade gliomas, all patients had conventional postoperative fractionated external-beam radiotherapy. The doses were 5583 ± 342 vs. 5345 ± 261 cGy (P = NS) for low- vs. high-grade gliomas, respectively. Intervals from surgery and conventional radiation (if given) to progression and SRS tended to be longer for low-grade gliomas: 37.5 ± 9.5 vs. 30.6 ± 11.1 months (P = NS) for low- vs. high-grade gliomas, respectively. High-grade gliomas were larger. The diameters of the collimators that allowed enclosure of the enhancing tumor volume within the specified treatment isodoses were 22.4 ± 2.0 mm for low-grade vs. 29.8 ± 2.8 mm for high-grade gliomas (P = 0.02, ANOVA). SRS doses and isodose percentiles were similar, however, for the two groups: 1650 ± 191 cGy and 79 ± 4.0% vs. 1932 ± 182 cGy and75 ± 3.5% for low- vs. high-grade gliomas, respectively (P = NS, dose and isodose). All patients with high-grade gliomas were followed until death. The mean survival after SRS was 11.6 ± 1.5 months (42 ± 12 months after surgery). Five of nine patients with low-grade gliomas expired 31.6 ± 6.0 months after SRS (P < 0.001, Kaplan–Meier log rank) (74.0 ± 16.0 months after surgery). The four survivors have been followed for 8, 13, 35, and 38 months after SRS, respectively. Multivariate analysis shows that the category of histologic grade correlates significantly with survival after radiosurgery (P = 0.01). SRS may be an important therapeutic option for patients with recurrent gliomas, regardless of their grade.     

Metastatic Hepatoma to the Brain Treated with Stereotactic Radiosurgery

Brain metastases from hepatocellular carcinoma are rare. Limited data from case reports indicates that these tumors may be relatively resistant to conventional whole brain radiotherapy. We report a case of hepatocellular carcinoma metastatic to the brain treated with stereotactic radiosurgery. This patient's tumors showed an excellent response to this modality and were successfully controlled for 13 months when she died of disseminated lung metastases.     

Stereotactic Radiosurgery of a Patient with Severe Kyphosis

A patient with a severe kyphotic deformity presented for stereotactic radiosurgery. In the supine position with the apex of the patient's kyphosis on the treatment couch, his head and buttocks were found to be approximately 30 cm from the table. Pretreatment consultation with the physicist and engineer was arranged. By creating a modified table mount for the head ring and a custom-molded Styrofoam cradle for the patient's pelvis, radiosurgery in the supine position was carried out without difficulty or patient discomfort. We describe the technical aspects of the treatment.     

Enlargement of a vestibular schwannoma after stereotactic radiotherapy

Summary.  Background: Radiosurgery has been increasingly advocated as a primary treatment for vestibular schwannoma (VS), and recently fractionation of the dose has been proposed as a method to decrease the risk of radiation injury when treating larger tumors.  Method: The authors describe a 48-year-old woman who presented with right-sided hearing loss and new-onset tinnitus, with a progressive decrease in facial sensation. The diagnosis of a large right cerebellopontine angle VS was made on magnetic resonance imaging (MRI). The patient was treated with a course of fractionated stereotactic radiotherapy (SRT) (5 treatments of 4 Gy to the 90% isodose line over a 3-week period).  Findings: Six months after the initiation of therapy, her symptoms increased, and a repeat MRI scan demonstrated that her tumor had increased in size, producing significant brainstem compression. She then underwent complete surgical resection of the tumor, with resolution of her symptoms.  Interpretation: Stereotactic radiosurgery has been effective in controlling small VSs with low complication rates. Larger tumors pose a risk for increasing in size and producing symptoms from mass effect with SRT. There are at present limited data demonstrating safety and efficacy of fractionated SRT for the treatment of larger tumors. Published online December 5, 2002  Correspondence: William T. Couldwell, M.D., Ph.D., Department of Neurosurgery, The University of Utah, Suite 3B409, 30 North 1900 East, Salt Lake City, UT 84132-2303.     

Pineal Region Choroid Plexus Papilloma Treated With Stereotactic Radiosurgery: A Case Study

The treatment of a patient with a third-ventricular choroid ple & papilloma is described. This relatively unusual lesion was treated with stereotactic radiosurgery. Follow-up at 17 months demonstrates substantial reduction in tumor volume and an excellent clinical outcome. The treatment of this patient suggests that radiosurgery may be an effective alternative to open surgical resection.     

A Review of Stereotactic Radiosurgery Practice in the Management of Skull Base Meningiomas

Gross total resection of skull base meningiomas poses a surgical challenge due to their proximity to neurovascular structures. Once the gold standard therapy for skull base meningiomas, microsurgery has been gradually replaced by or used in combination with stereotactic radiosurgery (SRS). This review surveys the safety and efficacy of SRS in the treatment of cranial base meningiomas including 36 articles from 1991 to 2010. SRS produces excellent tumor control with low morbidity rates compared with surgery alone for asymptomatic small skull base meningiomas, patients with risk factors precluding conventional surgery, and as adjuvant therapy for recurrent or residual lesions.     

Defining the Role of Stereotactic Radiosurgery Versus Microsurgery in the Treatment of Single Brain Metastases

Summary  Stereotactic radiosurgery (RS) and surgery have proved to be effective treatment modalities for brain metastasis. We followed 133 patients whose treatment for intracranial disease was either RS or a single surgical resection at the University of Vienna from August 1992 through October 1996. All patients who received additional Whole Brain Radiotherapy were included. This was a retrospective, case-control study comparing these treatment modalities.  Sixty-seven patients were treated by RS and 66 patients were treated by microsurgery. The median size of the treated lesions for RS patients was 7800 mm³, and 12500 mm³ for microsurgery patients, respectively. The median dose delivered to the tumour margin for RS patients was 17 gray.  The median survival for patients after RS was 12 months, and 9 months for patients after microsurgery. This difference was not statistically significant (p=0.19). Comparison of local tumour control, defined as absence of regrowth of a treated lesion, showed that tumours following RS had a preferred local control rate (p<0.05). Univariate and multivariate analysis showed that this fact was due to a greater response rate of “radioresistant” metastasis to RS (p<0.005). Postradiosurgical complications included the onset of peritumoural oedema (n=5) and radiation necrosis (n=1). Two patients after microsurgery experienced local wound infection. One postoperative death occurred due to pulmonary embolism in this group.  On the basis of our data we conclude that RS and microsurgery combined with Whole Brain Radiotherapy are comparable modalities in treating single brain metastasis. Concerning morbidity and local tumour control, in particular in cases of “radioresistant” primary tumours, RS is superior. Therefore we advocate RS except for cases of large tumours (>3 cm in maximum diameter) and for those with mass effect.