Clinical efficacy and safety of surface imaging guided radiosurgery (SIG-RS) in the treatment of benign skull base tumors.

Frameless, surface imaging guided radiosurgery (SIG-RS) is a novel platform for stereotactic radiosurgery (SRS) wherein patient positioning is monitored in real-time through infra-red camera tracking of facial topography. Here we describe our initial clinical experience with SIG-RS for the treatment of benign neoplasms of the skull base. We identified 48 patients with benign skull base tumors consecutively treated with SIG-RS at a single institution between 2009 and 2011. Patients were diagnosed with meningioma (n = 22), vestibular schwannoma (n = 20), or nonfunctional pituitary adenoma (n = 6). Local control and treatment-related toxicity were retrospectively assessed. Median follow-up was 65 months (range 61-72 months). Prescription doses were 12-13 Gy in a single fraction (n = 18), 8 Gy × 3 fractions (n = 6), and 5 Gy × 5 fractions (n = 24). Actuarial tumor control rate at 5 years was 98%. No grade ≥3 treatment-related toxicity was observed. Grade ≤2 toxicity was associated with symptomatic lesions (p = 0.049) and single fraction treatment (p = 0.005). SIG-RS for benign skull base tumors produces clinical outcomes comparable to conventional frame-based SRS techniques while enhancing patient comfort.

Neurocognitive assessment following whole brain radiation therapy and radiosurgery for patients with cerebral metastases.

The treatment of metastatic brain lesions remains a central challenge in oncology. Because most chemotherapeutic agents do not effectively cross the blood-brain barrier, it is widely accepted that radiation remains the primary modality of treatment. The mode by which radiation should be delivered has, however, become a source of intense controversy in recent years. The controversy involves whether patients with a limited number of brain metastases should undergo whole brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS) delivered only to the radiographically visible tumours. Survival is comparable for patients treated with either modality. Instead, the controversy involves the neurocognitive function (NCF) of radiating cerebrum that appeared radiographically normal relative to effects of the growth from micro-metastatic foci. A fundamental question in this debate involves quantifying the effect of WBRT in patients with cerebral metastasis. To disentangle the effects of WBRT on neurocognition from the effects inherent to the underlying disease, we analysed the results from randomised controlled studies of prophylactic cranial irradiation in oncology patients as well as studies where patients with limited cerebral metastasis were randomised to SRS versus SRS+WBRT. In aggregate, these results suggest deleterious effects of WBRT in select neurocognitive domains. However, there are insufficient data to resolve the controversy of upfront WBRT versus SRS in the management of patients with limited cerebral metastases.

A survey of stereotactic body radiotherapy use in the United States.

BACKGROUND: Stereotactic body radiotherapy (SBRT) is a technique used to deliver high, ablative doses of radiation in a limited number of fractions to ≥ 1 extracranial target(s). To the authors' knowledge, the prevalence of SBRT use among radiation oncologists in the United States is unknown. METHODS: A random sample of 1600 American radiation oncologists was surveyed via e-mail and facsimile (fax) regarding SBRT usage, including year of adoption, motivations, disease sites treated, and common prescriptions used. RESULTS: Of 1373 contactable physicians, 551 responses (40.1%) were received. The percentage of physicians using SBRT was 63.9% (95% confidence interval, 60%-68%), of whom nearly half adopted it in 2008 or later. The most commonly cited reasons for adopting SBRT were to allow the delivery of higher than conventional radiation doses (90.3%) and to allow retreatment (73.9%) in select patients. Academic physicians were more likely to report research as a motivation for SBRT adoption, whereas physicians in private practice were more likely to list competitive reasons. Among SBRT users, the most common disease sites treated were lung (89.3%), spine (67.5%), and liver (54.5%) tumors. Overall, 76.0% of current SBRT users planned to increase their use, whereas 66.5% of nonusers planned to adopt the technology in the future. CONCLUSIONS: SBRT has rapidly become a widely adopted treatment approach among American radiation oncologists. Further research and prospective trials are necessary to assess the benefits and risks of this novel technology.

Longitudinal MRI evidence for decreased survival among periventricular glioblastoma.

While the prognosis of patients with glioblastoma (GBM) remains poor despite recent therapeutic advances, variable survival times suggest wide variation in tumor biology and an opportunity for stratified intervention. We used volumetric analysis and morphometrics to measure the spatial relationship between subventricular zone (SVZ) proximity and survival in a cohort of 39 newly diagnosed GBM patients. We collected T2-weighted and gadolinium-enhanced T1-weighted magnetic resonance images (MRI) at pre-operative, post-operative, pre-radiation therapy, and post-radiation therapy time points, measured tumor volumes and distances to the SVZ, and collected clinical data. Univariate and multivariate Cox regression showed that tumors involving the SVZ and tumor growth rate during radiation therapy were independent predictors of shorter progression-free and overall survival. These results suggest that GBMs in close proximity to the ependymal surface of the ventricles convey a worse prognosis-an observation that may be useful for stratifying treatment.

DNA damage response and repair: insights into strategies for radiation sensitization of gliomas.

The incorporation of radiotherapy into multimodality treatment plans has led to significant improvements in glioma patient survival. However, local recurrence from glioma resistance to ionizing radiation remains a therapeutic challenge. The tumoricidal effect of radiation therapy is largely attributed to the induction of dsDNA breaks (DSBs). In the past decade, there have been tremendous strides in understanding the molecular mechanisms underlying DSB repair. The identification of gene products required for DSB repair has provided novel therapeutic targets. Recent studies revealed that many US FDA-approved cancer agents inhibit DSB repair by interacting with repair proteins. This article will aim to provide discussion of DSB repair mechanisms to provide molecular targets for radiation sensitization of gliomas and a discussion of FDA-approved cancer therapies that modulate DSB repair to highlight opportunities for combination therapy with radiotherapy for glioma therapy.

Observed magnetic resonance imaging changes in pediatric patients treated with stereotactic radiosurgery for intracranial tumors.

PURPOSE: This study seeks to characterize magnetic resonance imaging (MRI) changes following stereotactic radiosurgery (SRS) of pediatric brain malignancies. METHODS: Serial MRI evaluations were performed on 21 lesions treated with SRS for either medulloblastoma (n=12), juvenile pilocytic astrocytoma (n=4), ependymoma (n=2), atypical rhabdoid teratoid tumor (n=2), or pineocytoma (n=1). Prescription doses ranged from 14 to 30 Gy in one to five fractions. Tumor response was qualified as complete (CR), partial (PR), stable disease (SD), or progressive disease (PD) according to the RECIST v1.1. Median radiographic follow-up after SRS was 17 months. RESULTS: A total of 80 follow-up MRI scans were reviewed with a median of eight per patient. During serial MRI evaluation, eight lesions met criteria for PD at a median of 6 months. However, of these, three (37%) represented transient tumor edema with two lesions later developing a CR at a median of 15 months and one persisting as SD at 12 months. The remaining five lesions were true local failures. Of the 13 lesions that did not show evidence of PD, a CR was obtained in 11 lesions at a median of 3 months (range, 2-6), and SD was seen in the remaining two tumors at last follow-up. CONCLUSION: Lesion enlargement following SRS for pediatric intracranial tumors is common, and a proportion of patients meeting requirements for PD at early radiographic follow-up may later develop complete resolution of their lesions. Physicians should be aware of these radiographic changes to avoid unwarranted medical and surgical interventions.

Intracranial application of IMRT based radiosurgery to treat multiple or large irregular lesions and verification of infra-red frameless localization system.

We have employed a frameless localization system for intracranial radiosurgery, utilizing a custom biteblock with fiducial markers and an infra-red camera for set-up and monitoring patient position. For multiple brain metastases or large irregular lesions, we use a single-isocenter intensity-modulated approach. We report our quality assurance measurements and our experience using Intensity Modulated Radiosurgery (IMRS) to treat such intracranial lesions. A phantom with integrated targets and fiducial markers was utilized to test the positional accuracy of the system. The frameless localization system was used for patient setup and target localization as well as for motion monitoring during treatment. Inverse optimization planning gave satisfactory dose coverage and critical organ sparing. Patient setup was guided by the infrared camera through fine adjustment in three translational and three rotational degrees for isocenter localization and verified by orthogonal kilovoltage (kV) images, taken before treatment to ensure the accuracy of treatment. The relative localization of the camera based system was verified to be highly accurate along three translational directions of couch motion and couch rotation. After verification, we began treating patients with this technique. About 8-12 properly selected fixed beams with a single isocenter were sufficient to achieve good dose coverage and organ sparing. Portal dosimetry with an Electronic Portal Imaging Device (EPID) and kV images provided excellent quality assurance for the IMRS plan and patient setup. The treatment time was less than 60 min to deliver doses of 16-20 Gy in a single fraction. The camera-based system was verified for positional accuracy and was deemed sufficiently accurate for stereotactic treatments. Single isocenter IMRS treatment of multiple brain metastases or large irregular lesions can be done within an acceptable treatment time and gives the benefits of dose-conformity and organ-sparing, easy plan QA, and patient setup verification.

Optically-guided frameless linac-based radiosurgery for brain metastases: clinical experience.

The purpose of this study was to describe our clinical experience using optically-guided linear accelerator (linac)-based frameless stereotactic radiosurgery (SRS) for the treatment of brain metastases. Sixty-five patients (204 lesions) were treated between 2005 and 2008 with frameless SRS using an optically-guided bite-block system. Patients had a median of 2 lesions (range, 1-13). Prescription dose ranged from 14 to 22 Gy (median, 18 Gy) and was given in a single fraction. Clinical and radiographic evaluation occurred every 2-4 months following treatment. At a median follow-up of 6.2 months, actuarial survival at 12 months was 40% [95% confidence interval (CI), 28-52). Of 135 lesions that were evaluable for local control (LC), 119 lesions (88%) did not show evidence of progression. Actuarial 12 month LC was 76% (95% CI, 66-86). Tumors 2 cm. Adverse events occurred in three patients (5%). Optically-guided linac-based frameless SRS can produce clinical outcomes that compare favorably to frame-based techniques. As this technique is convenient to use and allows for the uncomplicated delivery of hypofractionated radiotherapy, frameless SRS will likely have an increasingly important role in the management of brain metastases.

Dosimetric comparison of intensity-modulated radiosurgery and helical tomotherapy for the treatment of multiple intracranial metastases.

The purpose of this study was to evaluate the dosimetry of single fraction, single-isocenter intensity-modulated radiosurgery (IMRS) plans for multiple intracranial metastases and to compare Helical Tomotherapy (HT). Ten treatment plans with 3-6 brain metastases treated with IMRS were re-planned with HT. The mean number of lesions was 5 and mean PTV 22 cm(3). The prescribed dose was 16-20 Gy. The mean V100% was similar for IMRS and HT, and the mean conformity index was 1.4, mean Paddick confirmity index was 0.7, and mean MDPD was 1.1 for both. The mean gradient index was similar for both. The mean 50% _isodose volume was 179.2 cm(3) for IMRS and 277.0 cm(3) for HT (p=0.01). The mean maximum doses to organs at risk were lower for IMRS except brainstem and right optic nerve. For brain, the integral dose was 5.1 and 6.8 Gy-kg (p<0.001) and mean dose 4.0 and 5.4 Gy (p<0.001) for IMRS and HT, respectively. The mean treatment times were 23 (IMRS) and 41 (HT) minutes. Conformity and homogeneity indices were equivalent and sparing of the organs at risk was clinically acceptable for both IMRS and HT. Though the gradient index was similar for IMRS and HT, the mean 50% isodose volume and integral dose to normal brain were lower for IMRS as was treatment time.

Initial clinical experience with frameless optically guided stereotactic radiosurgery/radiotherapy in pediatric patients.

OBJECTIVE: The objective of this study is to report our initial experience treating pediatric patients with central nervous system tumors using a frameless, optically guided linear accelerator. MATERIALS AND METHODS: Pediatric patients were selected for treatment after evaluation by a multidisciplinary neuro-oncology team including neurosurgery, neurology, pathology, oncology, and radiation oncology. Prior to treatment, all patients underwent treatment planning using magnetic resonance imaging (MRI) and treatment simulation on a standard computed tomography scanner (CT). For CT simulation, patients were fitted with a customized plastic face mask with a bite block attached to an optical array with four reflective markers. After ensuring adequate reproducibility, these markers were tracked during treatment by an infra-red camera. All treatments were delivered on a Varian Trilogy linear accelerator. The follow-up period ranges from 1-18 months, with a median follow-up of 6 months. RESULTS: Nine patients, ages ranging from 12 to 19 years old (median age 15 years old), with a variety of tumors have been treated. Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1). We followed patients for a median of 12 months (range 3-18 months) with no in-field failures and were able to obtain encouraging toxicity profiles. CONCLUSION: Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity.

Percutaneous feeding tubes in patients with head and neck cancer: rethinking prophylactic placement for patients undergoing chemoradiation.

OBJECTIVES: Although intensified therapy has contributed to improved outcomes for patients with head and neck cancer, acute toxicity has increased as well. To lessen the severity of nutritional compromise in these patients, our institutional protocol has been to routinely place feeding tubes before the initiation of therapy. This investigation details the toxicities associated with feeding tube placement and predictors for duration of tube dependence. MATERIALS AND METHODS: The records of the Radiation Oncology Department at Emory Clinic were reviewed for patients receiving definitive radiotherapy between 6/1/2003 and 6/1/2006. The records of the subset of patients with feeding tube placement before the initiation of therapy were then reviewed for toxicities as well as length of time of tube dependence. RESULTS: There were 102 eligible patients. Radiotherapy was delivered with concomitant chemotherapy in all. Median time with feeding tube in place for all patients was 4.4 months (range, 0.2-28.9 months). For 82 patients with eventual tube removal, the median time of tube dependence was 3.8 months (range, 1.4-28.9 months). Risk factors for prolonged tube dependence are analyzed; on multivariate analysis, patient age, T stage, and nodal status remained significant. The most common complication was tube replacement, with 11.8% of all tubes requiring replacement. Infection and pain occurred in 8.8% and 5.9% of patients, respectively. CONCLUSION: Feeding tubes are required for more than 2 months after combined modality treatment of head and neck cancer. They are generally well tolerated, but toxicities are not trivial: more than 10% require replacement and more than 8% of patients develop infection at the insertion site. We are assessing their routine placement in light of these data.

Early clinical results from chemoradiation with 5-fluorouracil and oxaliplatin for locally advanced rectal cancer.

PURPOSE: Preoperative chemoradiation with 5-fluorouracil (5-FU) has improved local control and resectability in patients with locally advanced rectal adenocarcinoma. The possible benefit of adding oxaliplatin is being investigated. We present background on the use of oxaliplatin as well as institutional experience assessing treatment tolerability and early outcome data. PATIENTS AND METHODS: From August 2001 to August 2006, 15 patients were treated with concurrent 5-FU, oxaliplatin, and radiation. Each had locally advanced rectal carcinoma with staging as follows: T3 (10 patients), T4 (5 patients), N1 (3 patients), and M1 (1 patient). Three patients were treated for local recurrence; 2 had received previous radiation therapy. All patients received continuous-infusion 5-FU at 225 mg/m2 per day. The oxaliplatin dose was 70 mg/m2 in 1 patient and 85 mg/m2 in the others, administered every other week x 3 weeks starting on day 1 of radiation. Resection followed completion of radiation by 6 weeks. RESULTS: The treatment was tolerable, with the most frequent hematologic toxicity being grade 1/2 anemia. Twelve patients were evaluable, with 11 treated preoperatively. All were able to undergo resection with negative margins, with T stage at resection as follows: T4 (2 patients, 1 with 5% viable tumor), T3 (4 patients), T2 (1 patient), T1 (2 patients); there were pathologic complete responses in 4 patients. At resection, 2 patients had N2 disease; 1 of these was also found to have a peritoneal metastasis. Two patients with clinical N1 disease initially were N0 at resection. With median follow-up of 13 months (range, 4-36 months), 9 patients have clinically no evidence of disease. There have been no local recurrences and 1 death from disease. CONCLUSION: We present tolerability and early clinical efficacy data for patients treated with concurrent 5-FU and oxaliplatin chemoradiation. The oxaliplatin-based regimen was tolerable. All patients were able to undergo resection with negative margins, with encouraging downstaging, local control, and survival.

Quantitative evaluation of a cone-beam computed tomography-planning computed tomography deformable image registration method for adaptive radiation therapy.

Deformable (non-rigid) registration is an essential tool in both adaptive radiation therapy and image-guided radiation therapy to account for soft-tissue changes during the course of treatment. The evaluation method most commonly used to assess the accuracy of deformable image registration is qualitative human evaluation. Here,we propose a method for systematically measuring the accuracy of an algorithm in recovering artificially introduced deformations in cases of rigid geometry, and we use that method to quantify the ability of a modified basis spline (B-Spline) registration algorithm to recover artificially introduced deformations. The evaluation method is entirely computer-driven and eliminates biased interpretation associated with human evaluation; it can be applied to any chosen method of image registration. Our method involves using planning computed tomography (PCT) images acquired with a conventional CT simulator and cone-beam computed tomography (CBCT) images acquired daily by a linear accelerator-mounted kilovoltage image system in the treatment delivery room. The deformation that occurs between the PCT and daily CBCT images is obtained using a modified version of the B-Spline deformable model designed to overcome the low soft-tissue contrast and the artifacts and distortions observed in CBCT images. Clinical CBCT images and contours of phantom and central nervous system cases were deformed (warped) with known random deformations. In registering the deformed with the non-deformed image sets, we tracked the algorithm's ability to recover the original, non-deformed set. Registration error was measured as the mean and maximum difference between the original and the registered surface contours from outlined structures. Using this approach, two sets of tests can be devised. To measure the residual error related to the optimizer's convergence performance, the warped CBCT image is registered to the unwarped version of itself, eliminating unknown factors such as noise and positioning errors. To study additional errors introduced by artifacts and noise in the CBCT image, the warped CBCT image is registered to the original PCT image. Using a B-Spline deformable image registration algorithm, mean residual error introduced by the algorithm's performance on noise-free images was less than 1 mm, with a maximum of 2 mm. The chosen deformable image registration model was capable of accommodating significant variability in structures over time, because the artificially introduced deformation magnitude did not significantly influence the residual error. On the second type of test, noise and artifacts reduced registration accuracy to a mean of 1.33 mm and a maximum of 4.86 mm.The accuracy of deformable image registration can be easily and consistently measured by evaluating the algorithm's ability to recover artificially introduced deformations in rigid cases in which the true solution is known a priori. The method is completely automated, applicable to any chosen registration algorithm, and does not require user interaction of any kind.

Quantification of dosimetric impact of implementation of on-board imaging (OBI) for IMRT treatment of head-and-neck malignancies.

Implementation of daily kilovoltage imaging for setup verification improves the reproducibility of treatment by eliminating small random setup errors. We evaluate the dosimetric consequences of such shifts, not yet evaluated, in a group of head-and-neck cancer patients (ENT) treated with intensity modulated radiation therapy (IMRT) at Emory University. Twelve patients with ENT malignancies were analyzed. On-Board Imaging (OBI) was used in at least 70% of each patient's treatment sessions. An isodose distribution was generated for each fraction, with the isocenter shifted to its calculated location prior to OBI repositioning. These plans were summed and then compared to the simulation plan for coverage of target structures. For these 12 patients, there were a total of 18 planning target volumes (PTV). The mean (range) percent reduction in minimum dose was 12.1% (-1.0 to 43.3). For 10 right necks and 9 left necks treated, the mean percent reduction in minimum dose was 11.8% (-0.6 to 39.7) and 13.3% (-3.6 to 31.2), respectively. The mean reduction in mean dose to the PTV was 1.3% (0 to 5.1). The mean reduction in mean dose to the right and left necks was 1.0% (0.2 to 3.9) and 1.13% (0.4 to 3.4), respectively. From this analysis, we conclude that the shifts made were small and random, with essentially no change in mean dose delivered to target structures. There is, however, significant improvement in the minimum dose delivered. Underdosing even a small portion of the tumor potentially sacrifices the probability of local control; correcting these setup errors seems desirable.

Clinical practice patterns of lung stereotactic body radiation therapy in the United States: a secondary analysis.

OBJECTIVES: Stereotactic body radiation therapy (SBRT) is a technique used to deliver high, ablative doses of radiation in a limited number of fractions to ≥1 extracranial target(s). Although recent studies have shown that SBRT provides effective local tumor control in medically inoperable early-stage lung cancer patients, its implementation in clinical practice is unknown. METHODS: A random sample of 1600 American radiation oncologists was surveyed regarding lung SBRT usage, including year adopted, most common prescription, respiratory motion management, and target localization. A biological equivalent dose (BED) was calculated using the linear quadratic model with α/ß=10. Spearman rank correlation coefficients (r(s)) were calculated to identify factors associated with BED. RESULTS: Of 1373 contactable physicians, 551 responses (40%) were received. Of 510 evaluable responses, 275 physicians (54%) reported using lung SBRT, over half of whom adopted it in 2008 or later. The most commonly reported prescriptions were 20 Gy×3 (22%), 18 Gy×3 (21%), and 12 Gy×4 (17%). Three fraction regimens were most common (48%), with nearly all (89%) prescribing ≥18 Gy/fraction. The median BED was 132 Gy, with 95% of reported prescriptions having BED≥100 Gy. Factors associated with increased BED included use of fiducial markers (r(s)=0.26, P<0.001), use of planar imaging (r(s)=0.18, P<0.01), and years of experience with lung SBRT (r(s)=0.13, P=0.04). CONCLUSIONS: Lung SBRT has rapidly become a widely adopted treatment approach in the United States with a range of varying implementations. Further research and additional prospective trials are necessary to optimize this novel approach.

Prospective study of functional bone marrow-sparing intensity modulated radiation therapy with concurrent chemotherapy for pelvic malignancies.

PURPOSE: To test the hypothesis that intensity modulated radiation therapy (IMRT) can reduce radiation dose to functional bone marrow (BM) in patients with pelvic malignancies (phase IA) and estimate the clinical feasibility and acute toxicity associated with this technique (phase IB). METHODS AND MATERIALS: We enrolled 31 subjects (19 with gynecologic cancer and 12 with anal cancer) in an institutional review board-approved prospective trial (6 in the pilot study, 10 in phase IA, and 15 in phase IB). The mean age was 52 years; 8 of 31 patients (26%) were men. Twenty-one subjects completed (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) simulation and magnetic resonance imaging by use of quantitative IDEAL (IDEAL IQ; GE Healthcare, Waukesha, WI). The PET/CT and IDEAL IQ were registered, and BM subvolumes were segmented above the mean standardized uptake value and below the mean fat fraction within the pelvis and lumbar spine; their intersection was designated as functional BM for IMRT planning. Functional BM-sparing vs total BM-sparing IMRT plans were compared in 12 subjects; 10 were treated with functional BM-sparing pelvic IMRT per protocol. RESULTS: In gynecologic cancer patients, the mean functional BM V(10) (volume receiving ≥10 Gy) and V(20) (volume receiving ≥20 Gy) were 85% vs 94% (P<.0001) and 70% vs 82% (P<.0001), respectively, for functional BM-sparing IMRT vs total BM-sparing IMRT. In anal cancer patients, the corresponding values were 75% vs 77% (P=.06) and 62% vs 67% (P=.002), respectively. Of 10 subjects treated with functional BM-sparing pelvic IMRT, 3 (30%) had acute grade 3 hematologic toxicity or greater. CONCLUSIONS: IMRT can reduce dose to BM subregions identified by (18)F-fluorodeoxyglucose-PET/CT and IDEAL IQ. The efficacy of BM-sparing IMRT is being tested in a phase II trial.

Patterns of imaging failures in glioblastoma patients treated with chemoradiation: a retrospective study.

Glioblastoma multiforme (GBM) is the most common primary brain tumor of adults and carries a poor prognosis. This study sought to investigate recurrence patterns of GBM treated with temozolomide-based chemoradiation. Records for 31 patients treated for newly diagnosed GBM between 2007 and 2009 were retrospectively analyzed. Ten patients received maximal surgical resection followed by conventionally fractionated radiation (CFR) to a median dose of 60 Gy with concurrent and planned adjuvant temozolomide. Twelve patients were treated with maximal surgical debulking, intracavitary brachytherapy (ICB), and external beam radiation therapy with concurrent and planned adjuvant temozolomide. The remaining 9 patients had unresectable disease and underwent biopsy followed by a hypofractionated course of radiation to a median dose of 60 Gy over 10 fractions. Tumor failure was classified as local, marginal, or distant according to whether the recurrence was completely inside, crossed, or completely outside the 100% isodose line. With a median follow-up of 12.6 months, 5 patients were lost to follow-up, while the remaining 26 patients (100%) developed recurrent disease. The first failures totaled 29 discrete lesions, of which 15 (52%), 6 (21%), and 8 (28%) were local, marginal, and distant failures at median times of 6.8, 10.1, and 7.9 months, respectively. Marginal or distant failure was more likely in ICB patients as compared to CFR patients. While local failure predominated, distant failures were not uncommon, particularly at later time points. As local control of GBM improves, further study is needed to identify and appropriately treat patients susceptible to distant failure.

Initial clinical experience with a frameless and maskless stereotactic radiosurgery treatment.

PURPOSE: To evaluate the initial clinical experience with a frameless and maskless technique for stereotactic radiosurgery using minimal patient immobilization and real-time patient motion monitoring during treatment. We focus on the evaluation of the patient treatment process. METHODS AND MATERIALS: The study considered the first 23 patients treated with this technique. Head positioning was achieved with a patient-specific head mold made out of expandable foam that conforms to the patient's head. The face of the patient is left open for maximal comfort and so that motion of a region of interest consisting of the forehead, nose, eyes, and temporal bones can be monitored during treatment using a video surface imaging system (VisionRT Inc, London, UK). Initial setup of the patient was performed with the surface imaging system using the surface of the patient obtained from the treatment planning computed tomographic (CT) scan. The initial setup was confirmed and finalized with cone-beam CT (CBCT) prior to treatment. The shifts for final setup based on the CBCT and the duration of all the steps in the treatment process were recorded. Patients were monitored during treatment with surface imaging, and a beam hold-off was initiated when the patient's motion exceeded a prespecified tolerance. RESULTS: The average total setup time including surface imaging and CBCT was 26 minutes, while the portion corresponding to surface imaging was 14 minutes. The average treatment time from when the patient was placed on the treatment table until the last treatment beam was 40 minutes. Eight (35%) patients needed repositioning during the treatment. The average shifts identified from CBCT after initial setup with surface imaging were 1.85 mm in the anterior-posterior direction, and less than 1.0 mm in the lateral and superior-inferior directions. The longest treatment times (including beam hold-offs) happened for patients who fell asleep on the treatment table and were moving involuntarily. CONCLUSIONS: The frameless and maskless treatment using minimal immobilization and surface imaging has proven to be reasonably fast for routine clinical use. We observed that patient compliance is important. An additional degree of semi-rigid immobilization would be helpful for patients who fall asleep and involuntarily move during the procedure.

Frameless, real-time, surface imaging-guided radiosurgery: clinical outcomes for brain metastases.

BACKGROUND: Frameless stereotactic radiosurgery is commonly used to treat intracranial metastases, but mask-based immobilization can be uncomfortable for patients. OBJECTIVE: To describe the clinical outcomes using a novel real-time, frameless, surface imaging--guided radiosurgery (SIG-RS) technique to treat brain metastases. METHODS: Data were prospectively gathered for 44 consecutive patients totaling 115 intracranial metastases treated with SIG-RS in a median of 1 fraction (range, 1-5) to a median dose of 20 Gy (range, 15-30 Gy). Local control, regional control, and overall survival were estimated by the Kaplan-Meier method. RESULTS: Median follow-up for all patients was 6.0 months (range, 0.3-21.6 months), with 31 of 44 (70%) deceased at the time of analysis. The 35 patients (80%) with follow-up imaging totaled 88 lesions evaluable for local control. Actuarial 6- and 12-month local control was 90% (95% confidence interval, 82-98) and 76% (95% confidence interval, 60-91), respectively. Regional failure was observed in 16 patients (46%). The median actuarial overall survival was 7.7 months (95% confidence interval, 5.7-9.7). Analysis of the subset of 22 patients (55 lesions) who received SIG-RS alone (no prior treatment) in a single fraction yielded comparable clinical outcomes. Grade 3 or greater toxicity occurred in 4 patients (9%). The median treatment time from beam on to beam off was 15 minutes (range, 3-36 minutes). CONCLUSION: SIG-RS for treating intracranial metastases can produce clinical outcomes comparable to those with conventional frame-based and frameless stereotactic radiosurgery techniques while providing greater patient comfort with an open-faced mask and fast treatment times.

Novel use of the Contura for high dose rate cranial brachytherapy.

A popular choice for treatment of recurrent gliomas was cranial brachytherapy using the GliaSite Radiation Therapy System. However, this device was taken off the market in late 2008, thus leaving a treatment void. This case study presents our experience treating a cranial lesion for the first time using a Contura multilumen, high-dose-rate (HDR) brachytherapy balloon applicator. The patient was a 47-year-old male who was diagnosed with a recurrent right frontal anaplastic oligodendroglioma. Previous radiosurgery made him a good candidate for brachytherapy. An intracavitary HDR balloon brachytherapy device (Contura) was placed in the resection cavity and treated with a single fraction of 20 Gy. The implant, treatment, and removal of the device were all completed without incident. Dosimetry of the device was excellent because the dose conformed very well to the target. V90, V100, V150, and V200 were 98.9%, 95.7%, 27.2, and 8.8 cc, respectively. This patient was treated successfully using the Contura multilumen balloon. Contura was originally designed for deployment in a postlumpectomy breast for treatment by accelerated partial breast irradiation. Being an intracavitary balloon device, its similarity to the GliaSite system makes it a viable replacement candidate. Multiple lumens in the device also make it possible to shape the dose delivered to the target, something not possible before with the GliaSite applicator.