Markerless dynamic tumor tracking (MDTT) radiotherapy using diaphragm as a surrogate for liver targets.

PURPOSE: To assess the feasibility of using the diaphragm as a surrogate for liver targets during MDTT. METHODS: Diaphragm as surrogate for markers: a dome-shaped phantom with implanted markers was fabricated and underwent dual-orthogonal fluoroscopy sequences on the Vero4DRT linac. Ten patients participated in an IRB-approved, feasibility study to assess the MDTT workflow. All images were analyzed using an in-house program to back-project the diaphragm/markers position to the isocenter plane. ExacTrac imager log files were analyzed. Diaphragm as tracking structure for MDTT: The phantom "diaphragm" was contoured as a markerless tracking structure (MTS) and exported to Vero4DRT/ExacTrac. A single field plan was delivered to the phantom film plane under static and MDTT conditions. In the patient study, the diaphragm tracking structure was contoured on CT breath-hold-exhale datasets. The MDTT workflow was applied until just prior to MV beam-on. RESULTS: Diaphragm as surrogate for markers: phantom data confirmed the in-house 3D back-projection program was functioning as intended. In patients, the diaphragm/marker relative positions had a mean ± RMS difference of 0.70 ± 0.89, 1.08 ± 1.26, and 0.96 ± 1.06 mm in ML, SI, and AP directions. Diaphragm as tracking structure for MDTT: Building a respiratory-correlation model using the diaphragm as surrogate for the implanted markers was successful in phantom/patients. During the tracking verification imaging step, the phantom mean ± SD difference between the image-detected and predicted "diaphragm" position was 0.52 ± 0.18 mm. The 2D film gamma (2%/2 mm) comparison (static to MDTT deliveries) was 98.2%. In patients, the mean difference between the image-detected and predicted diaphragm position was 2.02 ± 0.92 mm. The planning target margin contribution from MDTT diaphragm tracking is 2.2, 5.0, and 4.7 mm in the ML, SI, and AP directions. CONCLUSION: In phantom/patients, the diaphragm motion correlated well with markers' motion and could be used as a surrogate. MDTT workflows using the diaphragm as the MTS is feasible using the Vero4DRT linac and could replace the need for implanted markers for liver radiotherapy.

In-vivo quality assurance of dynamic tumor tracking (DTT) for liver SABR using EPID images.

PURPOSE: To assess dynamic tumor tracking (DTT) target localization uncertainty for in-vivo marker-based stereotactic ablative radiotherapy (SABR) treatments of the liver using electronic-portal-imaging-device (EPID) images. The Planning Target Volume (PTV) margin contribution for DTT is estimated. METHODS: Phantom and patient EPID images were acquired during non-coplanar 3DCRT-DTT delivered on a Vero4DRT linac. A chain-code algorithm was applied to detect Multileaf Collimator (MLC)-defined radiation field edges. Gold-seed markers were detected using a connected neighbor algorithm. For each EPID image, the absolute differences between the measured center-of-mass (COM) of the markers relative to the aperture-center (Tracking Error, (ET )) was reported in pan, tilt, and 2D-vector directions at the isocenter-plane. PHANTOM STUDY: An acrylic cube phantom implanted with gold-seed markers was irradiated with non-coplanar 3DCRT-DTT beams and EPID images collected. Patient Study: Eight liver SABR patients were treated with non-coplanar 3DCRT-DTT beams. All patients had three to four implanted gold-markers. In-vivo EPID images were analyzed. RESULTS: Phantom Study: On the 125 EPID images collected, 100% of the markers were identified. The average ± SD of ET were 0.24 ± 0.21, 0.47 ± 0.38, and 0.58 ± 0.37 mm in pan, tilt and 2D directions, respectively. Patient Study: Of the 1430 EPID patient images acquired, 78% had detectable markers. Over all patients, the average ± SD of ET was 0.33 ± 0.41 mm in pan, 0.63 ± 0.75 mm in tilt and 0.77 ± 0.80 mm in 2D directions The random 2D-error, σ, for all patients was 0.79 mm and the systematic 2D-error, Σ, was 0.20 mm. Using the Van Herk margin formula 1.1 mm planning target margin can represent the marker based DTT uncertainty. CONCLUSIONS: Marker-based DTT uncertainty can be evaluated in-vivo on a field-by-field basis using EPID images. This information can contribute to PTV margin calculations for DTT.

Four-dimensional dose calculations for dynamic tumour tracking with a gimbal-mounted linear accelerator.

PURPOSE: In this study we present a novel method for re-calculating a treatment plan on different respiratory phases by accurately modeling the panning and tilting beam motion during DTT (the "rotation method"). This method is used to re-calculate the dose distribution of a plan on multiple breathing phases to accurately assess the dosimetry. METHODS: sIMRT plans were optimized on a breath hold computed tomography (CT) image taken at exhale (BHexhale ) for 10 previous liver stereotactic ablative radiotherapy patients. Our method was used to re-calculate the plan on the inhale (0%) and exhale (50%) phases of the four-dimensional CT (4DCT) image set. The dose distributions were deformed to the BHexhale CT and summed together with proper weighting calculated from the patient's breathing trace. Subsequently, the plan was re-calculated on all ten phases using our method and the dose distributions were deformed to the BHexhale CT and accumulated together. The maximum dose for certain organs at risk (OARs) was compared between calculating on two phases and all ten phases. RESULTS: In total, 26 OARs were examined from 10 patients. When the dose was calculated on the inhale and exhale phases six OARs exceeded their dose limit, and when all 10 phases were used five OARs exceeded their limit. CONCLUSION: Dynamic tumor tracking plans optimized for a single respiratory phase leave an OAR vulnerable to exceeding its dose constraint during other respiratory phases. The rotation method accurately models the beam's geometry. Using deformable image registration to accumulate dose from all 10 breathing phases provides the most accurate results, however it is a time consuming procedure. Accumulating the dose from two extreme breathing phases (exhale and inhale) and weighting them properly provides accurate results while requiring less time. This approach should be used to confirm the safety of a DTT treatment plan prior to delivery.

Visual Outcomes and Local Control After Fractionated Stereotactic Radiotherapy for Optic Nerve Sheath Meningioma.

PURPOSE: To review the outcomes of patients with optic nerve sheath meningiomas (ONSM) treated with fractionated stereotactic radiotherapy. METHODS: Patient characteristics, treatment, and outcomes were analyzed for all patients with primary and secondary ONSM treated from 2001 to 2012. Clinically significant visual acuity change was defined as a 2-line change on the Snellen eye chart from pre-fractionated stereotactic radiotherapy. RESULTS: Forty-one patients were treated: 23 patients with primary ONSM and 18 patients with secondary ONSM. The median age at diagnosis was 56 years. The median visual follow up was 3.8 years and the median radiologic follow up was 4.4 years. At diagnosis, 36% had normal vision (20/20-20/40), 10% had mild impairment (<20/40-20/60), 20% had moderate visual impairment (<20/60-20/200), 27% had severe impairment (<20/200), and 7% had no light perception. Common acute side effects were headache (32%) and nausea (15%); 15% of patients required corticosteroids during stereotactic radiotherapy. Chronic toxicities included retinopathy (7%), pituitary dysfunction (13%), chronic ocular pain (5%), and cataracts (2%). Visual acuity was stable in 65%, improved in 27%, and decreased in 8% of patients. Visual fields were stable in 70%, improved in 21%, and reduced in 9%. Actuarial 5-year local control rates were 100% for primary ONSM and 88% for secondary ONSM. Actuarial 5-year visual preservation rates were 100% for primary ONSM and 86% for secondary ONSM. CONCLUSIONS: Fractionated stereotactic radiotherapy for primary and secondary ONSM was well tolerated and provides excellent local control and visual preservation. Longer follow up is required to determine the risk of late ocular and pituitary sequelae.

State of the ablation nation: a review of ablative therapies for cure in the treatment of hepatocellular carcinoma.

Primary liver cancer, mainly hepatocellular carcinoma, is one of the most common malignancies worldwide. Surgical management, either resection or transplantation, is considered definitive treatment, however, less than 20% of patients are ultimately candidates. Thermal ablation modalities such as radiofrequency ablation and microwave ablation have evolved such that these modalities have been applied with curative intent. Moreover, thermal ablation has demonstrated efficacy in treating early-stage tumors and can be offered as first-line treatment in patients with uncomplicated disease. Attributing to refinements in technology and techniques, recent studies evaluating stereotactic ablative body radiotherapy have shown promising results, while irreversible electroporation, an emerging modality, may further expand the role of ablative therapy in treating potentially resectable hepatocellular carcinoma.

Transanal Local Excision for Patients With Rectal Cancer: Can Radiation Compensate for What Is Perceived as a Nondefinitive Surgical Approach?

BACKGROUND: Total mesorectal excision has long been the standard of care for patients with rectal cancer. However, in select patients, local excision is an appropriate alternative option. The role of adjuvant radiation therapy in patients treated with local excision is controversial and evidence is lacking. OBJECTIVE: The purpose of this study was to report oncological outcomes of patients with rectal cancer treated with local excision and adjuvant radiation. DESIGN: This study was a retrospective chart review. SETTINGS: The study was conducted at the BC Cancer Agency, a tertiary referral hospital. PATIENTS: A total of 93 patients with node-negative rectal cancer treated with local excision and adjuvant radiotherapy between 2001 and 2010 were included in the study. MAIN OUTCOME MEASURES: Patient and tumor characteristics are reported. Five-year local control, progression-free survival, and overall survival were analyzed using Kaplan-Meier methods. RESULTS: Five-year overall survival, local control, and progression-free survival for patients treated with local excision and adjuvant radiotherapy were 78.5%, 86.1%, and 83.8%. In T1 disease, local control was 92.5%. LIMITATIONS: Referral bias, selection bias, lack of uniform surveillance, and retrospective analysis are the study limitations. CONCLUSIONS: Local excision with adjuvant radiotherapy provides a good level of local control in T1 disease and remains a good treatment option for patients who are either medically not suitable for a more radical surgical approach or who refuse this procedure. Local excision and radiotherapy should not be advocated in T2/T3 disease; however, it can provide a good alternative in those patients who are not fit enough for a more radical operation.

Stereotactic Radiosurgery for Metastases in Eloquent Central Brain Locations.

BACKGROUND: To examine stereotactic radiosurgery (SRS) following whole brain radiotherapy for metastases in eloquent, central brain locations: brainstem, thalamus, and basal ganglia. METHODS: We conducted a retrospective review of patients with metastases in eloquent, central brain locations who were treated with SRS between January 2000 and April 2012. All patients had whole brain radiotherapy. Patients eligible for SRS had one to three brain metastases, metastasis size ≤4 cm, and Karnofsky performance status ≥70. Local progression-free survival and overall survival were calculated using the Kaplan-Meier method. RESULTS: For 24 patients, the median age was 50 years (range, 36-73). Metastases by location were: 11 brainstem, 9 thalamus, and 5 basal ganglia. The median metastasis size was 15 mm (range, 2-33) and the median SRS dose prescription was 15 Gy (range, 12-24). The median local progression-free survival was 13.7 months and median overall survival was 16.4 months. Compared with a cohort of 188 patients with noneloquent brain metastases receiving a median dose of 24 Gy, overall survival of 10.8 months was not significantly different (p=0.16). The only symptomatic complication was grade 2 headache in 8.3%. Asymptomatic adverse radiologic events were radionecrosis in two (8.3%), peritumoural edema in four (16.7%), and hemorrhage in one patient (4.2%). CONCLUSIONS: Lower SRS marginal doses do not appear to compromise survival in patients with eloquently located brain metastases compared with higher doses for other brain metastases, with minimal symptomatic complications.

Greater inflammatory activity and blunted glucocorticoid signaling in monocytes of chronically stressed caregivers.

Chronic stress is associated with morbidity and mortality from numerous conditions, many of whose pathogenesis involves persistent inflammation. Here, we examine how chronic stress influences signaling pathways that regulate inflammation in monocytes. The sample consisted of 33 adults caring for a family member with glioblastoma and 47 controls whose lives were free of major stressors. The subjects were assessed four times over eight months. Relative to controls, caregivers' monocytes showed increased expression of genes bearing response elements for nuclear-factor kappa B, a key pro-inflammatory transcription factor. Simultaneously, caregivers showed reduced expression of genes with response elements for the glucocorticoid receptor, a transcription factor that conveys cortisol's anti-inflammatory signals to monocytes. Transcript origin analyses revealed that CD14+/CD16- cells, a population of immature monocytes, were the predominate source of inflammatory gene expression among caregivers. We considered hormonal, molecular, and functional explanations for caregivers' decreased glucocorticoid-mediated transcription. Across twelve days, the groups displayed similar diurnal cortisol profiles, suggesting that differential adrenocortical activity was not involved. Moreover, the groups' monocytes expressed similar amounts of glucocorticoid receptor protein, suggesting that differential receptor availability was not involved. In ex vivo studies, subjects' monocytes were stimulated with lipopolysaccharide, and caregivers showed greater production of the inflammatory cytokine interleukin-6 relative to controls. However, no group differences in functional glucocorticoid sensitivity were apparent; hydrocortisone was equally effective at inhibiting cytokine production in caregivers and controls. These findings may help shed light on the mechanisms through which caregiving increases vulnerability to inflammation-related diseases.

MPNST after Radiosurgery: A Report and Review of the Literature.

OBJECTIVE: To report an unusual case of malignant degeneration in a ganglioneuroma of the jugular foramen post stereotactic radiosurgery as well as to systematically review the pertinent literature involving radiosurgery associated malignancies. BACKGROUND: Ganglioneuromas are uncommon lesions of the peripheral nervous system and infrequently reported in the head and neck region. There have been no previously described cases of ganglioneuromas occurring in the jugular foramen. Malignant degeneration of these lesions is rarely described, especially in the context of radiosurgery. Radiosurgery associated malignancies overall are exceptionally rare and only a limited number of cases have been reported. RESULTS/CONCLUSIONS: We describe a case of a ganglioneuroma occurring in the jugular foramen and mimicking the appearance of a jugular foramen schwannoma. This lesion underwent stereotactic radiosurgery and developed a delayed degeneration into a malignant nerve sheath tumor. The occurrence of ganglioneuroma in this region has not been previously described and presumed malignant degeneration is even rarer. This case highlights a previously understated risk associated with stereotactic radiation treatments. To date, 33 previous cases of stereotactic radiosurgery associated malignancies have been reported. We review the pertinent details of these cases. We caution that as follow up periods and awareness increases, reports such as this may become increasingly common.Tumeurs malignes des gaines nerveuses périphériques après la radiochirurgie : à propos d'un cas et revue de littérature.

Stereotactic Ablative Radiation Therapy for Colorectal Liver Metastases.

INTRODUCTION: Stereotactic Ablative Radiation Therapy (SABR) is a therapeutic option for patients with inoperable oligometastatic colorectal carcinoma (CRC). Given the scarcity of prospective data on outcomes of SABR for metastatic CRC, this study aims to review SABR outcomes and determine predictive factors of local control (LC) and survival in patients with liver metastases from CRC. MATERIALS AND METHODS: A retrospective review of SABR for CRC liver metastases between 2011 and 2019 was undertaken. Endpoints included LC, overall survival (OS), progression-free survival (PFS) and time to restarting systemic therapy. Univariate (UVA) and multivariable analyses (MVA) were performed to identify predictive factors. RESULTS: Forty-eight patients were identified. The total number of tumors treated was 58. Median follow-up was 26.6 months. LC at 1, 2 and 3 years was 92.7%, 80.0%, and 61.2% respectively. Median time to local failure was 40.0 months (95% CI 31.8-76.1 months). Median OS was 31.9 months (95% CI 20.6-40.0 months). OS at 1, 2, and 3 years was 79.2%, 61.7%, and 44.9% respectively. Thirty-three patients (69%) restarted systemic therapy after completion of SABR. Median time to restarting chemotherapy was 11.0 months (95% CI 7.1-17.6 months). Systemic therapy free survival at 1, 2, and 3 years was 45.7%, 29.6%, and 22.6% respectively. On MVA, inferior LC was influenced by GTV volume ≥40 cm3 (HR: 3.805, 95% CI 1.376-10.521, P = .01) and PTV D100% BED <100 Gy10 (HR 2.971, 95% CI 1.110-7.953; P = .03). Inferior OS was associated with PTV volume ≥200 cm3 (HR 5.679, 95% CI 2.339-13.755; P < .001). CONCLUSION: SABR is an effective therapeutic option for selected patients with CRC liver metastases providing acceptable LC within the first 2 years. In many cases, it provides meaningful chemotherapy-free intervals. Higher biological effective doses are required to enhance LC.

Stereotactic fractionated radiotherapy for cavernous venous malformations (hemangioma) of the orbit.

PURPOSE: Cavernous malformations (hemangioma) of the orbit, when symptomatic, can often be treated successfully with complete surgical excision. However, when they involve local structures in their capsule, are situated in the orbital apex, or extend through the superior orbital fissure, the risks of surgery increase significantly. In such cases, alternative treatment modalities can be explored. In this study, the authors report on the use of fractionated stereotactic radiotherapy (SFRT) for the treatment of surgically complicated cavernous malformations. METHODS: In this retrospective cohort study, the authors reviewed the clinical and radiologic records of 5 patients treated with SFRT over the past 5 years. RESULTS: Patients ranged in age from 30 to 65 years, and 3 out of 5 were female. Two cases involved the cavernous sinus, one involved the ophthalmic artery, one involved the posterior ciliary artery, and the last traversed the superior orbital fissure. Four had significant visual field defects. Each was treated with SFRT. A total dose of 4000 cGy divided into 20,200 cGy fractions was applied for 3 cases, while 2 other cases were treated with total doses of 4563 and 4959 cGy divided into 28 × 162 cGy and 29 × 171 cGy fractions, respectively. Rapid resolution of visual field defect was noted by 3 months, and overall tumor shrinkage was on average 60% (range: 32-79%). Follow-up was on average 23.4 months (range: 5-50 months). No complications of treatment were noted. CONCLUSIONS: For symptomatic cavernous malformations demonstrating anatomical position that may increase risk of surgical excision, SFRT is an effective and safe method to control lesion size and improve visual function.

Survival and Recurrence Outcomes Following Adjuvant Radiotherapy for Grade 2 Intracranial Meningiomas: 13-Year Experience in a Tertiary-Care Center.

OBJECTIVE: We sought to evaluate overall survival (OS) and local recurrence (LR) in patients with grade 2 meningiomas treated with adjuvant radiotherapy compared to surgery alone at time of diagnosis. METHODS: All patients at the authors' institution between 2007 and 2020 were retrospectively reviewed. OS, LR, and treatment toxicities were assessed. Sensitivity analyses were performed for patients with initial gross total resection (GTR) and subtotal resection (STR). Kaplan-Meier analyses and log-rank test for significance were used to compare surgery alone and adjuvant radiotherapy groups. RESULTS: We included 189 patients with mean age 57.4 ± 14.6 years. Patients were 64% female, and median follow-up was 64 (interquartile range: 20-96) months. At initial treatment, 21 patients received adjuvant radiotherapy and 168 received surgery alone. There was no significant difference for OS (hazard ratio = 1.3 [95% confidence interval 0.4-4.5], P = 0.92) overall or when limited to GTR (P = 0.38) or STR (P = 0.85). There was no significant difference in LR overall (P = 0.75) or when restricted to GTR (P = 0.77) or STR (P = 0.20). No patient had radiotherapy stopped or altered because of side effects; however, 71.4% reported tolerable side effects during the treatment period and 14.3% reported chronic side effects persisting longer than 12 months post treatment. CONCLUSIONS: In a large retrospective cohort, we found no survival or local recurrence benefit to adjuvant radiotherapy in treatment of grade 2 meningiomas. Sensitivity analysis limited to initial GTR and STR also failed to demonstrate any OS or LR benefit with adjuvant radiotherapy. In our experience, there is limited utility to upfront adjuvant radiotherapy following initial surgical resection in the treatment of grade 2 meningiomas.

Patients with pretreatment leukoencephalopathy and older patients have more cognitive decline after whole brain radiotherapy.

PURPOSE: To investigate predictors of cognitive decline after whole brain radiotherapy (WBRT) for brain metastases. METHODS: A secondary analysis of a phase 2 clinical trial was conducted in patients who received stereotactic radiosurgery for 1-10 brain metastases and WBRT (NCT01046123). The Montreal Cognitive Assessment (MoCA) was performed at baseline and every 3 months after WBRT. Baseline T2-weighted fluid attenuation inversion recovery magnetic resonance imaging was independently assessed by two neuroradiologists for the presence of white matter hyperintensities (WMH) using the Fazekas visual rating scale. WMH were also manually segmented for volumetric analysis. Univariable and multivariable logistic regression were used to test the association between baseline variables and MoCA score decline. RESULTS: Forty-six patients survived ≥ 3 months after treatment. Age (OR 1.12 (1.04-1.21), p < 0.01), baseline WMH volume (OR 1.20, 95% CI 1.06-1.52, p = 0.02) and baseline Fazekas score ≥ 3/6 (OR 6.4, 95% CI 1.7-24.7, p < 0.01) were predictive of MoCA score decline. In multivariable analysis, age was the only significant predictor of MoCA decline. However, all three patients with pre-treatment leukoencephalopathy (Fazekas score = 6/6) had notable adverse outcomes due to cognitive impairment: one required full-time home nursing support and two were institutionalized. CONCLUSION: A greater decline in cognition after WBRT was observed in older patients and patients with a higher baseline WMH burden. Although this study is small and hypothesis-generating, we propose that radiation oncologists should exercise caution in prescribing WBRT if leukoencephalopathy is present on pre-treatment imaging. TRIAL REGISTRATION: clinicaltrials.gov identifier NCT01046123. First posted January 11, 2010. https://clinicaltrials.gov/ct2/show/NCT01046123.

Persistent Disparities in Survival for Patients with Glioblastoma.

BACKGROUND: Glioblastoma (GBM) is the most common malignant primary brain cancer in adults. Recent efforts have elucidated genetic features of tumor cells and thus enhanced our knowledge of GBM pathophysiology. The most recent clinical trials report median overall survival between 14 and 20 months. However, population level outcomes are quite variable and there is a paucity of such data within the literature. METHODS: Three hundred seventy-two patients with GBM were diagnosed in the Canadian province of British Columbia between January 2013 and January 2015 and 278 patients had surgery. Of these, 268 had surgery in British Columbia and we have performed a retrospective review of their survival outcomes. RESULTS: Our results indicate a median age of 61.8 years at time of diagnosis, with a slight preponderance of male patients. The median overall survival was 10 months for patients in our cohort. As expected, patients older than the age of 65 and those with worse initial Karnofsky Performance Status scores had a poorer prognosis. Moreover, we have found extent of resection, treatment strategies, and treatment location affect overall survival. CONCLUSIONS: The present study highlights factors that affect patient survival after surgery in British Columbia. Our data are gathered within a single-payer, high-resource setting which removes possible confounders in outcome analysis. We find persistent differences in overall survival when compared with clinical trials and the Surveillance, Epidemiology, and End Results database. Further efforts should ensure access to the gold standard of care. All neuro-oncology centers should analyze the real-world outcomes of their local glioblastoma treatment strategies. Knowledge of the variance from expected and comparative results are fundamental for appropriate patient care.

Stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma: imaging evaluation post treatment.

Surgical resection, when feasible, is the standard of care for hepatocellular carcinoma. However, many tumours are not resectable at the time of diagnosis. Recently, stereotactic body radiation therapy (SBRT) has emerged as a non-invasive local therapy for both non-resectable primary hepatic malignancies as well as hepatic metastases. Knowledge of the expected hepatic parenchymal appearance post treatment, as well as potential pitfalls and complications, is essential for accurate evaluation of treatment response. This pictorial review provides a fundamental description of the SBRT technique, outlines the expected cross-sectional imaging appearances of tumour response, and highlights potential pitfalls in interpretation. The expected liver parenchymal changes post-SBRT are also reviewed, along with some common radiation-induced complications.

Population-Based Study of Stereotactic Radiosurgery or Fractionated Stereotactic Radiation Therapy for Vestibular Schwannoma: Long-Term Outcomes and Toxicities.

PURPOSE: To examine long-term local control of vestibular schwannoma and side effects in patients treated with stereotactic radiosurgery (SRS) and fractionated stereotactic radiation therapy (SRT) in British Columbia. METHODS AND MATERIALS: From August 1998 to May 2009, 207 patients were treated with radiation therapy (RT) at British Columbia Cancer Agency. 136 (66%) received SRS, and 71 (34%) received SRT. Dose prescriptions were 50 Gy/25 fractions for SRT and 12 Gy/1 fraction for SRS. Our multidisciplinary provincial neuro-stereotactic conference recommended SRT for tumors >3 cm and for patients with serviceable hearing (Gardner-Robertson classes I and II). RESULTS: Median follow-up was 7.7 years to the last MRI and 6.4 years to the last clinical assessment. Local control for SRS versus SRT was 94% versus 87% at 5 years and 90% versus 85% at 10 years (P=.2). Five- and 10-year actuarial rates of RT-induced trigeminal nerve dysfunction were 25% and 25% after SRS, compared with 7% and 12% after SRT (P=.01). Five- and 10-year actuarial rates of RT-induced facial nerve dysfunction were 15% and 15% after SRS, versus 13% and 15% after SRT (P=.93). In the 49 patients with serviceable hearing at baseline who were treated with SRT, hearing preservation was 55% at 3 years, 37% at 5 years, and 29% at 7 years. In multivariable analysis, better pretreatment ipsilateral pure tone average was significantly associated with hearing preservation (hazard ratio 1.03; 95% confidence interval 1.00-1.07; P=.04). CONCLUSIONS: Both SRS and SRT provided excellent long-term local control of vestibular schwannoma. Stereotactic radiosurgery was associated with higher rates of trigeminal nerve dysfunction. Even with a fractionated course, hearing preservation declined steadily with long-term audiometric follow-up.

Hearing preservation following fractionated stereotactic radiotherapy for vestibular schwannomas: prognostic implications of cochlear dose.

OBJECT: The goal in this study was to evaluate hearing preservation rates and to determine prognostic factors for this outcome following fractionated stereotactic radiotherapy (FSRT) of vestibular schwannoma. METHODS: Thirty-four consecutive patients with serviceable hearing who received FSRT between May 1998 and December 2003 were identified. Clinical and audiometry data were collected prospectively. The prescription dose was 45 Gy in 25 fractions prescribed to the 90% isodose line. The median follow-up duration was 36.5 months (range 12-85 months). The actuarial 2- and 4-year local control rates were 100 and 95.7%, respectively. Permanent trigeminal and facial nerve complications were 0 and 6%, respectively. The actuarial 2- and 3-year serviceable hearing preservation rates were both 63%. The median loss in speech reception threshold was 15 dB (range--10 to 65 dB). The radiotherapy dose to the cochlea was the only significant prognostic factor for hearing deterioration. Radiotherapy dose to the cochlear nucleus, patient age, sex, pre-FSRT hearing grade, tumor volume, and intracanalicular tumor volume failed to show any significance as prognostic factors. RESULTS: Five cases were replanned with four different radiotherapy techniques (namely arcs, dynamic arcs, static conformal fields, and intensity-modulated radiotherapy), with the cochlea defined as an organ at risk. In all cases, replanning resulted in statistically significant reduction in radiation to the cochlea (p = 0.001); however, no single replanning technique was found to be superior. CONCLUSIONS: The radiation dose to the cochlea is strongly predictive for subsequent hearing deterioration. It is essential for the cochlea to be outlined as an organ at risk, and for radiation techniques to be optimized, to improve long-term hearing preservation.

Does intensity modulation improve healthy tissue sparing in stereotactic radiosurgery of complex arteriovenous malformations?

This planning study evaluates the potential of intensity modulated treatment fields and inverse planning techniques in stereotactic radiosurgery to reduce healthy tissue dose. Twenty patients previously treated with stereotactic radiosurgery for arteriovenous malformation (AVM) were replanned with each of 4 techniques: circular non-coplanar arcs, dynamic arcs, static conformal fields, and intensity modulated radiosurgery (IMRS). Patients were selected having a maximum AVM dimension at least 20 mm, or volume greater than 10 cm(3). Target volumes ranged from 2.12 cm(3) to 13.87 cm(3) with a median of 6.03 cm(3). Resulting dose distributions show a statistically significant improvement in target conformality between circular arcs and all other techniques (p

Volumetric Radiosurgery for 1 to 10 Brain Metastases: A Multicenter, Single-Arm, Phase 2 Study.

PURPOSE: Interest is growing in treating multiple brain metastases with radiosurgery. We report on the effectiveness and tolerability of volumetric radiosurgery (VRS). METHODS AND MATERIALS: We enrolled patients with a ≥6-month estimated life expectancy and 1 to 10 brain metastases with a diameter of ≤3 cm at 5 cancer centers. Volumetric radiosurgery was delivered in 5 fractions with 98% target coverage, prescribed as 95% of 50 Gy (47.5 Gy in 5 fractions) to the metastases with no margin and 95% of 40 Gy (38 Gy in 5 fractions) to their 2-mm planning target volumes, concurrent with 20 Gy to the whole brain planning target volume. The treatment was delivered with daily image guidance using conventional linear accelerators and volumetric modulated arc therapy. A magnetic resonance imaging scan was obtained every 3 months. The primary endpoint was the 3-month objective response in the brain according to the Response Evaluation Criteria in Solid Tumors, version 1.1. The principal secondary endpoint was 1-year actuarial control of treated metastases. Toxicities were graded using the Common Terminology Criteria for Adverse Events, version 4.0. The present study is registered with ClinicalTrials.gov (clinicaltrials.gov identifier NCT01046123). RESULTS: From July 2010 to May 2013, 60 patients underwent VRS with 47.5 Gy in 5 fractions for 12 metastases in the thalamus and basal ganglia (deep metastases) and 207 non-deep metastases. The median follow-up period was 30.5 months, and the median survival was 10.1 months. For the 43 patients assessable at 3 months, the objective response in the brain was 56%. The treated metastases were controlled in 88% of patients at 1 year and 84% at 3 years. Overall survival did not differ for patients with 4 to 10 versus 1 to 3 metastases (hazard ratio 1.18, P=.6). The crude incidence of severe radionecrosis (grade 3-5) was 25% (3 of 12) per deep metastasis, 1.9% (4 of 219) per non-deep metastasis, and 10% (6 of 60) per patient. CONCLUSIONS: For non-deep brain metastases, 47.5 Gy in 5 fractions was tolerable. Volumetric radiosurgery was effective for long-term control of treated brain metastases.

Outcomes of Proton Beam Radiotherapy for Large Non-Peripapillary Choroidal and Ciliary Body Melanoma at TRIUMF and the BC Cancer Agency.

BACKGROUND AND PURPOSE: To report outcomes and toxicity after proton beam radiotherapy for non-peripapillary choroidal and ciliary body melanoma considered unsuitable for other eye-sparing therapies. MATERIALS AND METHODS: An existing database of 77 patients with non-peripapillary tumors treated at TRIUMF, Canada, including patient, tumor, and treatment characteristics, was updated with ocular complications and follow-up status from chart reviews. RESULTS: Most of the patients had large tumors: 61% were T3/T4 tumors (AJCC classification), while 48% were large by the Collaborative Ocular Melanoma Study classification. The median thickness was 7.1 mm, and the ciliary body was involved in 35%. After 5 and 10 years, the actuarial ocular tumor control rate was 85 and 85%, metastasis-free survival was 72 and 57%, overall survival was 77 and 63%, the enucleation rate was 22 and 22%, and complete blindness was found in 38 and 38%, respectively. On univariate analysis, patients with ciliary body involvement had significantly worse metastasis-free survival and overall survival rates compared to patients without ciliary body involvement (p < 0.001). CONCLUSIONS: Proton therapy for large anteriorly located tumors resulted in acceptable ocular tumor control and survival rates. The risk of blindness and severe toxicity requiring enucleation was low, and a substantial proportion of patients maintained useful vision.