66 research outputs found
Dosimetric evaluation of heterogeneity corrections for RTOG 0236: stereotactic body radiotherapy of inoperable stage I-II non-small-cell lung cancer.
PURPOSE: Using a retrospective analysis of treatment plans submitted from multiple institutions accruing patients to the Radiation Therapy Oncology Group (RTOG) 0236 non-small-cell stereotactic body radiotherapy protocol, the present study determined the dose prescription and critical structure constraints for future stereotactic body radiotherapy lung protocols that mandate density-corrected dose calculations.
METHOD AND MATERIALS: A subset of 20 patients from four institutions participating in the RTOG 0236 protocol and using superposition/convolution algorithms were compared. The RTOG 0236 protocol required a prescription dose of 60 Gy delivered in three fractions to cover 95% of the planning target volume. Additional requirements were specified for target dose heterogeneity and the dose to normal tissue/structures. The protocol required each site to plan the patient\u27s treatment using unit density, and another plan with the same monitor units and applying density corrections was also submitted. These plans were compared to determine the dose differences. Two-sided, paired Student\u27s t tests were used to evaluate these differences.
RESULTS: With heterogeneity corrections applied, the planning target volume receiving \u3e/=60 Gy decreased, on average, 10.1% (standard error, 2.7%) from 95% (p = .001). The maximal dose to any point \u3e/=2 cm away from the planning target volume increased from 35.2 Gy (standard error, 1.7) to 38.5 Gy (standard error, 2.2). CONCLUSION: Statistically significant dose differences were found with the heterogeneity corrections. The information provided in the present study is being used to design future heterogeneity-corrected RTOG stereotactic body radiotherapy lung protocols to match the true dose delivered for RTOG 0236
Quality assurance of radiotherapy in the ongoing EORTC 22042â26042 trial for atypical and malignant meningioma: Results from the dummy runs and prospective individual case Reviews
BACKGROUND: The ongoing EORTC 22042â26042 trial evaluates the efficacy of high-dose radiotherapy (RT) in atypical/malignant meningioma. The results of the Dummy Run (DR) and prospective Individual Case Review (ICR) were analyzed in this Quality Assurance (QA) study. MATERIAL/METHODS: Institutions were requested to submit a protocol compliant treatment plan for the DR and ICR, respectively. DR-plans (n=12) and ICR-plans (n=50) were uploaded to the Image-Guided Therapy QA Center of Advanced Technology Consortium server (http://atc.wustl.edu/) and were assessed prospectively. RESULTS: Major deviations were observed in 25% (n=3) of DR-plans while no minor deviations were observed. Major and minor deviations were observed in 22% (n=11) and 10% (n=5) of the ICR-plans, respectively. Eighteen% of ICRs could not be analyzed prospectively, as a result of corrupted or late data submission. CTV to PTV margins were respected in all cases. Deviations were negatively associated with the number of submitted cases per institution (p=0.0013), with a cutoff of 5 patients per institutions. No association (p=0.12) was observed between DR and ICR results, suggesting that DRâs results did not predict for an improved QA process in accrued brain tumor patients. CONCLUSIONS: A substantial number of protocol deviations were observed in this prospective QA study. The number of cases accrued per institution was a significant determinant for protocol deviation. These data suggest that successful DR is not a guarantee for protocol compliance for accrued patients. Prospective ICRs should be performed to prevent protocol deviations
Clinical outcomes and toxicity of proton beam radiation therapy for re-irradiation of locally recurrent breast cancer
Purpose: Repeat radiation therapy (RT) using photons/X-rays for locally recurrent breast cancer results in increased short and long-term toxicity. Proton beam RT (PBRT) can minimize dose to surrounding organs, thereby potentially reducing toxicity. Here, we report the toxicity and clinical outcomes for women who underwent re-irradiation to the chest wall for locally recurrent breast cancer using PBRT.
Materials and methods: This was a retrospective study analyzing 16 consecutive patients between 2013 and 2018 with locally recurrent breast cancer who underwent re-irradiation to the chest wall with PBRT. For the recurrent disease, patients underwent maximal safe resection, including salvage mastectomy, wide local excision, or biopsy only per surgeons recommendations. Systemic therapy was used per the recommendation of the medical oncologist. Patients were treated with median dose of 50.4 Cobalt Gray Equivalent (CGyE) in 28 fractions at the time of re-irradiation. Follow-up was calculated from the start of second RT course. Acute toxicities were defined as those occurring during treatment or up to 8âŻweeks after treatment. Late toxicities were defined as those occurring more than 8âŻweeks after the completion of therapy. Toxicities were based on CTCAE 4.0.
Results: The median age at original diagnosis and at recurrence was 49.8âŻyears and 60.2âŻyears, respectively. The median time between the two RT courses was 10.2 (0.7-20.2) years. The median follow-up time was 18.7 (2.5-35.2) months. No local failures were observed after re-irradiation. One patient developed distant metastasis and ultimately died. Grade 3-4 acute skin toxicity was observed in 5 (31.2%) patients. Four (25%) patients developed chest wall infections during or shortly (2âŻweeks) after re-irradiation. Late grade 3-4 fibrosis was observed in only 3 (18.8%) patients. Grade 5 toxicities were not observed. Hyperpigmentation was seen in 12 (75%) patients. Pneumonitis, telangiectasia, rib fracture, and lymphedema occurred in 2 (12.5%), 4 (25%), 1 (6.3%), and 1 (6.3%) patients, respectively.
Conclusions: Re-irradiation with PBRT for recurrent breast cancer has acceptable toxicities. There was a high incidence of acute grade 3-4 skin toxicity and infections, which resolved, however, with skin care and antibiotics. Longer follow-up is needed to determine long-term clinical outcomes
Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup
Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR < 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p
Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup
Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR < 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p
Does quality of radiation therapy predict outcomes of multicenter cooperative group trials? A literature review
Central review of radiation therapy (RT) delivery within multicenter clinical trials was initiated in the early 1970s in the United States. Early quality assurance publications often focused on metrics related to process, logistics, and timing. Our objective was to review the available evidence supporting correlation of RT quality with clinical outcomes within cooperative group trials. A MEDLINE search was performed to identify multicenter studies that described central subjective assessment of RT protocol compliance (quality). Data abstracted included method of central review, definition of deviations, and clinical outcomes. Seventeen multicenter studies (1980-2012) were identified, plus one Patterns of Care Study. Disease sites were hematologic, head and neck, lung, breast, and pancreas. Between 0 and 97% of treatment plans received an overall grade of acceptable. In 7 trials, failure rates were significantly higher after inadequate versus adequate RT. Five of 9 and 2 of 5 trials reported significantly worse overall and progression-free survival after poor-quality RT, respectively. One reported a significant correlation, and 2 reported nonsignificant trends toward increased toxicity with noncompliant RT. Although more data are required, protocol-compliant RT may decrease failure rates and increase overall survival and likely contributes to the ability of collected data to answer the central trial question
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