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International Journal of Radiation... May 2021We sought to investigate the tumor control probability (TCP) of vestibular schwannomas after single-fraction stereotactic radiosurgery (SRS) or hypofractionated SRS over... (Review)
Review
PURPOSE
We sought to investigate the tumor control probability (TCP) of vestibular schwannomas after single-fraction stereotactic radiosurgery (SRS) or hypofractionated SRS over 2 to 5 fractions (fSRS).
METHODS AND MATERIALS
Studies (PubMed indexed from 1993-2017) were eligible for data extraction if they contained dosimetric details of SRS/fSRS correlated with local tumor control. The rate of tumor control at 5 years (or at 3 years if 5-year data were not available) were collated. Poisson modeling estimated the TCP per equivalent dose in 2 Gy per fraction (EQD2) and in 1, 3, and 5 fractions.
RESULTS
Data were extracted from 35 publications containing a total of 5162 patients. TCP modeling was limited by the absence of analyzable data of <11 Gy in a single-fraction, variability in definition of "tumor control," and by lack of significant increase in TCP for doses >12 Gy. Using linear-quadratic-based dose conversion, the 3- to 5-year TCP was estimated at 95% at an EQD2 of 25 Gy, corresponding to 1-, 3-, and 5-fraction doses of 13.8 Gy, 19.2 Gy, and 21.5 Gy, respectively. Single-fraction doses of 10 Gy, 11 Gy, 12 Gy, and 13 Gy predicted a TCP of 85.0%, 88.4%, 91.2%, and 93.5%, respectively. For fSRS, 18 Gy in 3 fractions (EQD2 of 23.0 Gy) and 25 Gy in 5 fractions (EQD2 of 30.2 Gy) corresponded to TCP of 93.6% and 97.2%. Overall, the quality of dosimetric reporting was poor; recommended reporting guidelines are presented.
CONCLUSIONS
With current typical SRS doses of 12 Gy in 1 fraction, 18 Gy in 3 fractions, and 25 Gy in 5 fractions, 3- to 5-year TCP exceeds 91%. To improve pooled data analyses to optimize treatment outcomes for patients with vestibular schwannoma, future reports of SRS should include complete dosimetric details with well-defined tumor control and toxicity endpoints.
Topics: Dose Fractionation, Radiation; Humans; Linear Models; Models, Biological; Models, Theoretical; Neurofibromatosis 2; Neuroma, Acoustic; Poisson Distribution; Probability; Radiosurgery; Radiotherapy Dosage; Relative Biological Effectiveness; Time Factors; Treatment Outcome
PubMed: 33375955
DOI: 10.1016/j.ijrobp.2020.11.019 -
Acta Neurochirurgica Jan 2020There is little data on the cost of treating brain arteriovenous malformations (AVMs). The goal of this study then is to identify cost determinants in multimodal...
INTRODUCTION
There is little data on the cost of treating brain arteriovenous malformations (AVMs). The goal of this study then is to identify cost determinants in multimodal management of brain AVMs.
METHODS
One hundred forty patients with brain AVMs prospectively enrolled in the UCSF brain AVM registry and treated between 2012 and 2015 were included in the study. Patient and AVM characteristics, treatment type, and length of stay and radiographic evidence of obliteration were collected from the registry. We then calculated the cost of all inpatient and outpatient encounters, interventions, and imaging attributable to the AVM. We used generalized linear models to test whether there was an association between patient and AVM characteristics, treatment type, and cost and length of stay. We tested whether the proportion of patients with radiographic evidence of obliteration differed between treatment modalities using Fisher's exact test.
RESULTS
The overall median cost of treatment and interquartile range was $77,865 (49,566-107,448). Surgery with preoperative embolization was the costliest treatment at $91,948 (79,914-140,600), while radiosurgery was the least at $20,917 (13,915-35,583). In multi-predictor analyses, hemorrhage, Spetzler-Martin grade, and treatment type were significant predictors of cost. Patients who had surgery had significantly higher rates of obliteration compared with radiosurgery patients.
CONCLUSIONS
Hemorrhage, AVM grade, and treatment modality are significant cost determinants in AVM management. Surgery with preoperative embolization was the costliest treatment and radiosurgery the least; however, surgical cases had significantly higher rates of obliteration.
Topics: Adolescent; Adult; Child; Costs and Cost Analysis; Embolization, Therapeutic; Female; Health Care Costs; Humans; Intracranial Arteriovenous Malformations; Male; Middle Aged; Postoperative Hemorrhage; Radiosurgery
PubMed: 31760534
DOI: 10.1007/s00701-019-04134-6 -
PloS One 2022Cerebral arteriovenous malformations (AVMs) are challenging lesions, often requiring multimodal interventions; however, data on the efficacy of stereotactic radiosurgery...
BACKGROUND
Cerebral arteriovenous malformations (AVMs) are challenging lesions, often requiring multimodal interventions; however, data on the efficacy of stereotactic radiosurgery for cerebral AVMs are limited. This study aimed to evaluate the clinical and radiographic results following robotic radiosurgery, alone or in combination with endovascular treatment, and to investigate factors associated with obliteration and complications in patients with AVM.
METHODS
We retrospectively analyzed the clinical and imaging characteristics of 123 patients with AVMs of all Spetzler-Martin grades treated at two institutions by robotic radiosurgery in single-fraction doses (CyberKnife). Embolization was performed before radiosurgery in a subset of patients to attempt to downgrade the lesions. Factors associated with AVM obliteration and complications (toxicity) were identified via univariate and multivariate analyses.
RESULTS
The median follow-up time was 48.1 months (range, 3.6-123 months). Five patients were lost to follow-up. The obliteration rate in the 59 patients with a follow-up period exceeding four years was 72.8%. Complete obliteration and partial remission were achieved in 67 (56.8%) and 31 (26.3%) cases, respectively, whereas no change was observed in 20 cases (17.8%). Embolization was performed in 54/123 cases (43.9%). Complete and partial obliteration were achieved in 29 (55.7%) and 14 (26.9%) embolized patients, respectively. In the multivariate analysis, the factors associated with obliteration were age (p = .018) and the Spetzler-Martin grade (p = .041). Treatment-induced toxicity (radiation necrosis and/or edema) was observed in 15 cases (12.7%), rebleeding occurred in three cases (2.5%), and the rate of mortality associated with rebleeding was 1.7%.
CONCLUSIONS
CyberKnife radiosurgery is a valid approach for treating AVMs of all Spetzler-Martin-grades, with satisfactory obliteration rates, low toxicity, and a relatively rare incidence of rebleeding.
Topics: Follow-Up Studies; Humans; Intracranial Arteriovenous Malformations; Radiosurgery; Retrospective Studies; Robotic Surgical Procedures; Treatment Outcome
PubMed: 36137082
DOI: 10.1371/journal.pone.0266744 -
Radiotherapy and Oncology : Journal of... May 2023Radiation-induced brachial plexopathy (RIBP), resulting in symptomatic motor or sensory deficits of the upper extremity, is a risk after exposure of the brachial plexus...
INTRODUCTION
Radiation-induced brachial plexopathy (RIBP), resulting in symptomatic motor or sensory deficits of the upper extremity, is a risk after exposure of the brachial plexus to therapeutic doses of radiation. We sought to model dosimetric factors associated with risks of RIBP after stereotactic body radiotherapy (SBRT).
METHODS
From a prior systematic review, 4 studies were identified that included individual patient data amenable to normal tissue complication probability (NTCP) modelling after SBRT for apical lung tumors. Two probit NTCP models were derived: one from 4 studies (including 221 patients with 229 targets and 18 events); and another from 3 studies (including 185 patients with 192 targets and 11 events) that similarly contoured the brachial plexus.
RESULTS
NTCP models suggest ≈10% risks associated with brachial plexus maximum dose (D) of ∼32-34 Gy in 3 fractions and ∼40-43 Gy in 5 fractions. RIBP risks increase with increasing brachial plexus D. Compared to previously published data from conventionally-fractionated or moderately-hypofractionated radiotherapy for breast, lung and head and neck cancers (which tend to utilize radiation fields that circumferentially irradiate the brachial plexus), SBRT (characterized by steep dose gradients outside of the target volume) exhibits a much less steep dose-response with brachial plexus D > 90-100 Gy in 2-Gy equivalents.
CONCLUSIONS
A dose-response for risk of RIBP after SBRT is observed relative to brachial plexus D. Comparisons to data from less conformal radiotherapy suggests potential dose-volume dependences of RIBP risks, though published data were not amenable to NTCP modelling of dose-volume measures associated with RIBP after SBRT.
Topics: Humans; Radiosurgery; Radiotherapy Dosage; Retrospective Studies; Brachial Plexus Neuropathies
PubMed: 36842665
DOI: 10.1016/j.radonc.2023.109583 -
AJNR. American Journal of Neuroradiology Jan 2021T2 signal and FLAIR changes in patients undergoing stereotactic radiosurgery for brain AVMs may occur posttreatment and could result in adverse radiation effects. We...
BACKGROUND AND PURPOSE
T2 signal and FLAIR changes in patients undergoing stereotactic radiosurgery for brain AVMs may occur posttreatment and could result in adverse radiation effects. We aimed to evaluate outcomes in patients with these imaging changes, the frequency and degree of this response, and factors associated with it.
MATERIALS AND METHODS
Through this retrospective cohort study, consecutive patients treated with stereotactic radiosurgery for brain AVMs who had at least 1 year of follow-up MR imaging were identified. Logistic regression analysis was used to evaluate predictors of outcomes.
RESULTS
One-hundred-sixty AVMs were treated in 148 patients (mean, 35.6 years of age), including 42 (26.2%) pediatric AVMs. The mean MR imaging follow-up was 56.5 months. The median Spetzler-Martin grade was III. The mean maximal AVM diameter was 2.8 cm, and the mean AVM target volume was 7.4 mL. The median radiation dose was 16.5 Gy. New T2 signal and FLAIR hyperintensity were noted in 40% of AVMs. T2 FLAIR volumes at 3, 6, 12, 18, and 24 months were, respectively, 4.04, 55.47, 56.42, 48.06, and 29.38 mL Radiation-induced neurologic symptoms were encountered in 34.4%. In patients with radiation-induced imaging changes, 69.2% had new neurologic symptoms versus 9.5% of patients with no imaging changes (= .0001). Imaging changes were significantly associated with new neurologic findings (< .001). Larger AVM maximal diameter (= .04) and the presence of multiple feeding arteries (= .01) were associated with radiation-induced imaging changes.
CONCLUSIONS
Radiation-induced imaging changes are common following linear particle accelerator-based stereotactic radiosurgery for brain AVMs, appear to peak at 12 months, and are significantly associated with new neurologic findings.
Topics: Adolescent; Adult; Aged; Brain Edema; Child; Child, Preschool; Cohort Studies; Female; Humans; Intracranial Arteriovenous Malformations; Magnetic Resonance Imaging; Male; Middle Aged; Radiation Injuries; Radiosurgery; Retrospective Studies; Treatment Outcome
PubMed: 33214183
DOI: 10.3174/ajnr.A6880 -
Clinical Medicine (London, England) Jan 2023Most cancer-related deaths are due to metastatic disease. There is now an emerging evidence base suggesting that a subgroup of metastatic patients benefit significantly...
Most cancer-related deaths are due to metastatic disease. There is now an emerging evidence base suggesting that a subgroup of metastatic patients benefit significantly from local resection (surgery) or ablation (stereotactic ablative body radiation, SABR) of their metastatic sites. These patients are in what has been termed the 'oligometastatic state', a transitional window between local and disseminated disease where locally ablative, metastasis-directed therapy prolongs progression-free survival, improves overall survival and sometimes achieves cure. Appropriately selecting those who fit this oligometastatic phenotype, while integrating advances in ablative technologies such as SABR with modern systemic treatments, is an evolving challenge for oncologists.
Topics: Humans; Neoplasms; Radiosurgery
PubMed: 36697003
DOI: 10.7861/clinmed.2022-0559 -
Radiation Oncology (London, England) Jun 2021The purpose of this study is to evaluate inter- and intra-fraction organ motion as well as to quantify clinical target volume (CTV) to planning target volume (PTV)...
PURPOSE
The purpose of this study is to evaluate inter- and intra-fraction organ motion as well as to quantify clinical target volume (CTV) to planning target volume (PTV) margins to be adopted in the stereotactic treatment of early stage glottic cancer.
METHODS AND MATERIALS
Stereotactic body radiotherapy (SBRT) to 36 Gy in 3 fractions was administered to 23 patients with early glottic cancer T1N0M0. Patients were irradiated with a volumetric intensity modulated arc technique delivered with 6 MV FFF energy. Each patient underwent a pre-treatment cone beam computed tomography (CBCT) to correct the setup based on the thyroid cartilage position. Imaging was repeated if displacement exceeded 2 mm in any direction. CBCT imaging was also performed after each treatment arc as well as at the end of the delivery. Swallowing was allowed only during the beam-off time between arcs. CBCT images were reviewed to evaluate inter- and intra-fraction organ motion. The relationships between selected treatment characteristics, both beam-on and delivery times as well as organ motion were investigated.
RESULTS
For the population systematic (Ʃ) and random (σ) inter-fraction errors were 0.9, 1.3 and 0.6 mm and 1.1, 1.3 and 0.7 mm in the left-right (X), cranio-caudal (Y) and antero-posterior (Z) directions, respectively. From the analysis of CBCT images acquired after treatment, systematic (Ʃ) and random (σ) intra-fraction errors resulted 0.7, 1.6 and 0.7 mm and 1.0, 1.5 and 0.6 mm in the X, Y and Z directions, respectively. Margins calculated from the intra-fraction errors were 2.4, 5.1 and 2.2 mm in the X, Y and Z directions respectively. A statistically significant difference was found for the displacement in the Z direction between patients irradiated with > 2 arcs versus ≤ 2 arcs, (MW test, p = 0.038). When analyzing mean data from CBCT images for the whole treatment, a significant correlation was found between the time of delivery and the three dimensional displacement vector (r = 0.489, p = 0.055), the displacement in the Y direction (r = 0.553, p = 0.026) and the subsequent margins to be adopted (r = 0.626, p = 0.009). Finally, displacements and the subsequent margins to be adopted in Y direction were significantly greater for treatments with more than 2 arcs (MW test p = 0.037 and p = 0.019, respectively).
CONCLUSIONS
In the setting of controlled swallowing during treatment delivery, intra-fraction motion still needs to be taken into account when planning with estimated CTV to PTV margins of 3, 5 and 3 mm in the X, Y and Z directions, respectively. Selected treatments may require additional margins.
Topics: Cone-Beam Computed Tomography; Humans; Laryngeal Neoplasms; Organ Motion; Prognosis; Prospective Studies; Radiosurgery; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy Setup Errors; Radiotherapy, Intensity-Modulated; Surgery, Computer-Assisted
PubMed: 34118965
DOI: 10.1186/s13014-021-01833-2 -
Journal of Veterinary Internal Medicine Mar 2022The safety and efficacy of stereotactic body radiation therapy (SBRT) in the treatment of localized nasal lymphoma in cats has not been described.
BACKGROUND
The safety and efficacy of stereotactic body radiation therapy (SBRT) in the treatment of localized nasal lymphoma in cats has not been described.
HYPOTHESIS
Stereotactic body radiation therapy with or without adjuvant chemotherapy is an effective and well-tolerated treatment for localized nasal lymphoma in cats.
ANIMALS
Thirty-two client owned cats referred to Colorado State University for the treatment of nasal lymphoma.
METHODS
Retrospective study of cats treated with SBRT between 2010 and 2020 at Colorado State University. Diagnosis of nasal lymphoma was obtained via cytology or histopathology. Signalment, radiation protocol, concurrent treatments, adverse effects, and survival were recorded.
RESULTS
Progression free survival was 225 days (95% CI 98-514) and median survival time (MST) was 365 days (95% CI 123-531). No significant difference in survival was identified between cats that received 1 versus greater than 1 fraction (MST 427 vs. 123 days, P = 0.88). Negative prognostic factors included cribriform lysis (MST 121 vs. 876 days, P = 0.0009) and intracalvarial involvement (MST 100 vs. 438 days, P = 0.0007). Disease progression was noted in 38% (12/32), locally in 22% (7/32), and systemically in 16% (5/32). No cats developed acute adverse effects. Ten cats developed late adverse effects: keratitis/keratitis sicca (n = 2), alopecia (n = 4), and leukotrichia (n = 4). Twenty-four cats (75%) had signs consistent with chronic rhinitis.
CONCLUSIONS
SBRT is effective and well tolerated for treating localized nasal lymphoma in cats. Outcomes for cats with lower stage disease (canine modified Adam's stage 3 and lower) are comparable to historic data of cats treated with fractionated radiation therapy.
Topics: Animals; Cat Diseases; Cats; Dog Diseases; Dogs; Humans; Lymphoma; Nose Neoplasms; Radiosurgery; Retrospective Studies; Treatment Outcome
PubMed: 35188694
DOI: 10.1111/jvim.16388 -
International Journal of Radiation... Dec 2022To describe the long-term outcomes of a 5-fraction normal tissue tolerance adapted strategy for the management of oligometastases (OM).
PURPOSE
To describe the long-term outcomes of a 5-fraction normal tissue tolerance adapted strategy for the management of oligometastases (OM).
METHODS AND MATERIALS
Patients with histologically confirmed solid tumors, ≤5 extracranial metastases, suitable for a definitive approach for all metastatic lesions, at least one lesion suitable for Stereotactic Body Radiotherapy (SBRT), Eastern Coooperative Oncology Group Performance Status ≤2 were eligible. Treatment intervention was a 5-fraction (25-55 Gy) normal tissue adapted dosing strategy. The primary outcome was cumulative local progression rate at 12 months.
RESULTS
Between March 2013 and January 2018, 137 patients started SBRT. Median follow-up was 35.7 months. In addition, 107 (78%) patients had a solitary OM. The mean planning target volume D was 39.6 (standard deviation, 8.8; biological effective dose using an alpha/beta ratio of 10, 70.8) Gy. Mean planning target volume D was highest for lung lesions (48.7 [standard deviation, 4.7]; biological effective dose using an alpha/beta ratio of 10, 96.1) Gy but was <40 Gy for all other anatomic sites. Two grade 3 toxicities (gastrointestinal bleed) were observed with stomach D 30.3 Gy and 30.4 Gy. The cumulative local progression rate at 12 of 36 months was 16.1% (95% CI, 10-22) and 38.3% (95% CI 30-46.7); overall survival was 90% and 37%, and progression free survival was 58% and 19%, respectively. Mean symptom burden (Edmonton Symptom Assessment Total Score) worsened in patients with progressive disease (+8.8) at 12 months and was paralleled by changes in mean European Organization for Research and Treatment Quality of Life Core Questionnaire Summary Score and Global Health Quality of Life Score. Systemic therapy was initiated in 55% of patients at an average of 12.7 (standard deviation 12.4) months.
CONCLUSIONS
If long-term progression free survival is the primary goal of therapy, SBRT for OM achieved this in <20% of patients attributable to a high risk of distant failure. Favorable local progression free survival is accompanied by preservation of quality of life, avoidance of symptom progression and reduced need of antineoplastic therapies at 12 months. Information on symptom burden, quality of life, as well as pattern of antineoplastic therapy use after progressive disease is useful to support conversations between patients, families, and health care providers. Strategies to improve patient selection and reduce distant progression rate remain a priority for further study.
Topics: Humans; Radiosurgery; Prospective Studies; Quality of Life; Progression-Free Survival; Patient Reported Outcome Measures
PubMed: 35901981
DOI: 10.1016/j.ijrobp.2022.07.025 -
Neurology India 2023The optimal management of cavernous malformations (CMs) remains controversial. Over the past decade, stereotactic radiosurgery (SRS) has gained wider acceptance in the...
The optimal management of cavernous malformations (CMs) remains controversial. Over the past decade, stereotactic radiosurgery (SRS) has gained wider acceptance in the management of CMs, especially in those with deep location, eloquence, and where surgery is of high risk. Unlike arteriovenous malformations (AVMs), there is no imaging surrogate endpoint to confirm CM obliteration. Clinical response to SRS can only be gauged by a reduction in long-term CM hemorrhage rates. There is concern that the long-term benefits of SRS and the reduced rehemorrhage rate after a latency period of 2 years may only be a reflection of natural history. Of further concern is the development of adverse radiation effects (AREs), which were significant in the early experimental studies. The lessons learnt from that era have led to the progressive development of well-defined, lower marginal dose treatment protocols that have reported less toxicity (5%-7%) and consequently reduced morbidity. Currently, there is at least Class II, Level B evidence for use of SRS in solitary CMs with previous symptomatic hemorrhage in eloquent areas with high surgical risk. Recent prospective cohort studies observing untreated brainstem and thalamic CMs report significantly higher hemorrhage rates and neurological sequelae than the rates reported from contemporary pooled large natural history meta-analyses. Furthermore, this strengthens our recommendation for early proactive SRS in symptomatic deep-seated CMs due to the higher morbidity associated with observation and microsurgery. The key to successful outcomes for any surgical intervention is patient selection. We hope that our precis on contemporary SRS techniques in the management of CMs will assist this process.
Topics: Humans; Treatment Outcome; Follow-Up Studies; Radiosurgery; Intracranial Arteriovenous Malformations; Brain Stem; Retrospective Studies
PubMed: 37026340
DOI: 10.4103/0028-3886.373639