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Δευτέρα, 26 Μαρτίου 2018

Why validation of prognostic models matters?

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Publication date: Available online 26 March 2018
Source:Radiotherapy and Oncology
Author(s): Alex Zwanenburg, Steffen Löck
Prognostic models are powerful tools for treatment personalisation. However, not all proposed models work well when validated using new data, despite impressive results being reported initially. Here, we will use a hands-on approach to highlight important aspects of prognostic modelling, as well as to demonstrate methods to generate generalisable models.



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Clinical outcome after high-precision radiotherapy for skull base meningiomas: Pooled data from three large German centers for radiation oncology

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Publication date: Available online 26 March 2018
Source:Radiotherapy and Oncology
Author(s): Stephanie E. Combs, Mostafa Farzin, Julia Boehmer, Oliver Oehlke, Michael Molls, Jürgen Debus, Anca-Ligia Grosu
PurposeTo evaluate outcome in patients with base of skull meningiomas treated with modern high precision radiation therapy (RT) techniques.Patients and methods927 patients from three centers were treated with either radiosurgery or fractionated high-precision RT for meningiomas. Treatment planning was based on CT and MRI following institutional guidelines. For radiosurgery, a median dose of 13 Gy was applied, for fractionated treatments, a median dose of 54 Gy in 1.8 Gy single fractions was prescribed. Follow-up included a clinical examination as well as contrast-enhanced imaging. All patients were followed up prospectively after radiotherapy in the three departments within a strict follow-up regimen. The median follow-up time was 81 months (range 1–348 months).ResultsMedian local control was 79 months (range 1–348 months). Local control (LC) was 98% at 1 year, 94% at 3 years, 92% at 5 years and 86% at 10 years. There was no difference between radiosurgery and fractionated RT. We analyzed the influence of higher doses on LC and could show that dose did not impact LC. Moreover, there was no difference between 54 Gy and 57.6 Gy in the fractionated group. Side effects were below 5% in both groups without any severe treatment-related complications.DiscussionBased on the pooled data analysis this manuscript provides a large series of meningiomas of the skull base treated with modern high precision RT demonstrating excellent local control and low rates of side effects. Such data support the recommendation of RT for skull base meningiomas in the interdisciplinary tumor board discussions. The strong role of RT must influence treatment recommendations keeping in mind the individual risk–benefit profile of treatment alternatives.



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Clinical outcome after high-precision radiotherapy for skull base meningiomas: Pooled data from three large German centers for radiation oncology

S01678140.gif

Publication date: Available online 26 March 2018
Source:Radiotherapy and Oncology
Author(s): Stephanie E. Combs, Mostafa Farzin, Julia Boehmer, Oliver Oehlke, Michael Molls, Jürgen Debus, Anca-Ligia Grosu
PurposeTo evaluate outcome in patients with base of skull meningiomas treated with modern high precision radiation therapy (RT) techniques.Patients and methods927 patients from three centers were treated with either radiosurgery or fractionated high-precision RT for meningiomas. Treatment planning was based on CT and MRI following institutional guidelines. For radiosurgery, a median dose of 13 Gy was applied, for fractionated treatments, a median dose of 54 Gy in 1.8 Gy single fractions was prescribed. Follow-up included a clinical examination as well as contrast-enhanced imaging. All patients were followed up prospectively after radiotherapy in the three departments within a strict follow-up regimen. The median follow-up time was 81 months (range 1–348 months).ResultsMedian local control was 79 months (range 1–348 months). Local control (LC) was 98% at 1 year, 94% at 3 years, 92% at 5 years and 86% at 10 years. There was no difference between radiosurgery and fractionated RT. We analyzed the influence of higher doses on LC and could show that dose did not impact LC. Moreover, there was no difference between 54 Gy and 57.6 Gy in the fractionated group. Side effects were below 5% in both groups without any severe treatment-related complications.DiscussionBased on the pooled data analysis this manuscript provides a large series of meningiomas of the skull base treated with modern high precision RT demonstrating excellent local control and low rates of side effects. Such data support the recommendation of RT for skull base meningiomas in the interdisciplinary tumor board discussions. The strong role of RT must influence treatment recommendations keeping in mind the individual risk–benefit profile of treatment alternatives.



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Blindness after facial trauma: epidemiology, incidence and risk factors. a 27-year cohort study of 5708 patients.

This is a 27-year study of a cohort of 5708 patients who sustained maxillofacial fractures. Our purpose is to present the aetiology, mechanism of trauma, site and concomitant injuries that led to visual loss. We hypothesize that fractures caused by high energy impact of the midface may be associated with blindness. A discussion of the treatment approaches is also included.

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Demographics and referral patterns of a university-based oral maxillofacial radiology clinic over a 20 year period

– The aim of this study was to review the referral patterns, distribution of interpretations, and type of diagnostic imaging used in a university based oral maxillofacial radiology clinic for patients referred for consultation from both dental and non-dental clinicians.

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Management update of potentially premalignant oral epithelial lesions

The term oral potentially malignant disorders (OPMD) previously defined at the World Health Organisation (W.H.O) workshop in 2005 has now been redefined as potentially premalignant oral epithelial lesions (PPOELs). It is important to differentiate PPOEL's which are a broad term to define a wide variety of clinical lesions from oral epithelial dysplasia which should be reserved specifically for lesions with biopsy proven foci of dysplasia. Unfortunately, the nomenclature is not consistent and many times both terms PPOEL and dysplasia are used interchangeably which adds to confusion in the literature.

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Clinical outcome after high-precision radiotherapy for skull base meningiomas: Pooled data from three large German centers for radiation oncology

To evaluate outcome in patients with base of skull meningiomas treated with modern high precision radiation therapy (RT) techniques.

from Imaging via alkiviadis.1961 on Inoreader https://ift.tt/2GeW1K3

Why validation of prognostic models matters?

Prognostic models are powerful tools for treatment personalisation. However, not all proposed models work well when validated using new data, despite impressive results being reported initially. Here, we will use a hands-on approach to highlight important aspects of prognostic modelling, as well as to demonstrate methods to generate generalisable models.

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Dose escalation for prostate stereotactic ablative radiotherapy (SABR): Late outcomes from two prospective clinical trials

Optimal prostate SABR dose-fractionation is unknown. This study compares long-term outcomes from two prospective trials.

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Clinical Utility of Diffusion-Weighted Imaging in Spinal Infections

Abstract

Purpose

Both laboratory markers and radiographic findings in the setting of spinal infections can be nonspecific in determining the presence or absence of active infection, and can lag behind both clinical symptoms and antibiotic response. Magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has been shown to be helpful in evaluating brain abscesses but has not been commonly used in evaluating spinal infections. We aimed to correlate findings on DWI of the spine to results of microbiological sampling in patients with suspected spinal infections.

Methods

Patients who underwent MRI with DWI for suspicion of spinal infections and microbiological sampling from 2002 to 2010 were identified and reviewed retrospectively in this institutional review board approved study. In addition to DWI, scans included sagittal and axial T1, fast-spin echo (FSE) T2, and post-gadolinium T1 with fat saturation. Regions of interest were drawn on apparent diffusion coefficient (ADC) maps in the area of suspected infections, and ADC values were correlated with microbiological sampling.

Results

Of 38 patients with suspected spinal infections, 29 (76%) had positive microbiological sampling, and 9 (24%) had negative results. The median ADC value was 740 × 10−6 mm2/s for patients with positive microbiological sampling and 1980 × 10−6 mm2/s for patients with negative microbiological sampling (p < 0.001). Using an ADC value of 1250 × 10−6 mm2/s or less as the cut-off value for a positive result for spinal infection, sensitivity was 66%, specificity was 88%, positive predictive value was 95%, negative predictive value was 41% and accuracy was 70%.

Conclusion

In patients with suspected spine infection, ADC values on DWI are significantly reduced in those patients with positive microbiological sampling compared to patients with negative microbiological sampling. The DWI of the spine correlates well with the presence or absence of spinal infection and may complement conventional magnetic resonance imaging (MRI).



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Diagnostic performance of shoulder magnetic resonance arthrography for labral tears having surgery as reference: comparison of high-resolution isotropic 3D sequence (THRIVE) with standard protocol

Abstract

Purpose

To compare the diagnostic performance of T1 high-resolution isotropic volume excitation (THRIVE) sequence with that of a standard protocol for direct shoulder magnetic resonance arthrography (MRA) for the diagnosis of superior labral anterior-to-posterior (SLAP) and Bankart lesions, using arthroscopy findings as a reference standard.

Materials and methods

We retrospectively studied 84 patients who underwent direct shoulder 3T MRA using THRIVE and two-dimensional three-plane proton-density fat-suppressed (2D-PD-FS) sequences. One reviewer evaluated the contrast-to-noise ratio (CNR) as a quantitative image quality. Other two reviewers independently evaluated the subjective image noise, image sharpness, and radiologic diagnosis as qualitative image quality. Arthroscopic surgical findings were considered the reference standard. Wilcoxon rank sum, Chi-square/Fisher's exact, and DeLong's tests, as well as intraclass correlation coefficients (ICCs) were used to evaluate differences between THRIVE and 2D-PD-FS images.

Results

THRIVE images had significantly higher CNR (p < 0.001), and subjective ratings of image noise (p = 0.009) and sharpness (p = 0.039) than 2D-PD-FS images (p < 0.001). THRIVE images had similar (p ≥ 0.18) diagnostic performance (sensitivity, 93.0–97.2%; specificity, 95.8–100%; accuracy, 95.2–97.6%) for the diagnosis of SLAP and Bankart lesions with excellent agreement (ICC = 0.898–0.942) when compared to 2D-PD-FS images (sensitivity, 86.1–91.7%; specificity, 93.8–95.8%; accuracy, 90.5–92.9%; agreement, ICC = 0.782–0.858). The scan time was reduced by 69% for THRIVE sequence compared to 2D-PD-FS sequence (2 min 40 s vs. 8 min 40 s).

Conclusion

The THRIVE sequence may be helpful in the diagnosis of SLAP and Bankart lesions, and may be routinely used during direct shoulder 3T MRA.



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Trabecular structural changes in the mandibular condyle caused by degenerative osteoarthritis: a comparative study by cone-beam computed tomography imaging

Abstract

Objectives

Temporomandibular osteoarthritis causes pain and loss of function. In advanced cases, it may also result in destruction of joint cartilage surfaces and bone structure.

Methods

This study was performed to examine the potential changes in the condylar trabecular bone structure in patients with temporomandibular osteoarthritis. Condylar trabecular structures were compared between 35 healthy patients and 35 patients with temporomandibular osteoarthritis by a box-counting method using fractal dimensional analysis on cone-beam computed tomography images.

Results

The average fractal dimensions of patients with temporomandibular osteoarthritis and healthy patients were 1.18 and 1.23, respectively. This difference was statistically significant (p ≤ 0.05).

Conclusions

Our results add to the existing preliminary knowledge regarding the osteoporotic changes that occur in the trabecular structure under the subchondral bone, which is normally not seen on radiographic images, as well as the destruction and remodeling that occur on the condyle surface, which is visible on radiographic images.



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Comparison of detectability of breast cancer by abbreviated breast MRI based on diffusion-weighted images and postcontrast MRI

Abstract

Purpose

To compare the detectability of unenhanced abbreviated magnetic resonance imaging (MRI) based on diffusion-weighted imaging (DWI) and abbreviated postcontrast MRI for breast cancer.

Methods

The study population consisted of 87 patients undergoing breast MRI between December 2016 and March 2017 in a clinical setting. All breast MRIs were performed using a 1.5-T MRI scanner with a 16-channel breast radiofrequency coil. The abbreviated protocols based on DWI (AP1) and postcontrast MRI (AP2) were assessed independently by two radiologists. Sensitivity and specificity were calculated. Receiver operating characteristic analysis was performed and the areas under the curves (AUCs) were compared between AP1 and AP2.

Results

The study included 87 patients with 89 breast cancer lesions ≤ 2 cm in diameter. The sensitivity/specificity for AP1 and AP2 for reader 1 was 89.9/97.6% and 95.5/90.6%, respectively, and those for reader 2 was 95.5/94.1% and 98.9/94.1%, respectively. The AUCs for AP1 and AP2 for reader 1 were 0.9629 and 0.9640 (p = 0.95), respectively, and those for reader 2 were 0.9755 and 0.9843 (p = 0.46), respectively.

Conclusions

The detectability of the unenhanced abbreviated protocol based on DWI would be comparable to that of abbreviated postcontrast MRI for breast cancer.



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Soft tissue sarcomas: new opportunity of treatment with PARP inhibitors?

Abstract

Background

Poly(ADP-ribose) polymerases (PARP) are a large family of enzymes involved in several cellular processes, including DNA single-strand break repair via the base-excision repair pathway. PARP inhibitors exert antitumor activity by both catalytic PARP inhibition and PARP–DNA trapping, moreover PARP inhibition represents a potential synthetic lethal approach against cancers with specific DNA-repair defects. Soft tissue sarcoma (STSs) are a heterogeneous group of mesenchymal tumors with locally destructive growth, high risk of recurrence and distant metastasis.

Objectives

The purpuse of this review is to provide an overview of the main preclinical and clinical data on use of PARPi in STSs and of effect and safety of combination of PARPi with irradiation.

Results

Due to numerous genomic alterations in STSs, the DNA damage response pathway can offer an interesting target for biologic therapy. Preclinical and clinical studies showed promising results, with the most robust evidences of PARPi efficacy obtained on Ewing sarcoma bearing EWS–FLI1 or EWS–ERG genomic fusions. The activity of PARP inhibitors resulted potentiated by chemotherapy and radiation. Although mechanisms of synergisms are not completely known, combination of radiation therapy and PARP inhibitors exerts antitumor effect by accumulation of unrepaired DNA damage, arrest in G2/M, activity both on oxic and hypoxic cells, reoxygenation by effect on vessels and promotion of senescence. Early trials have shown a good tolerance profile.

Conclusions

The use of PARP inhibitors in advanced stage STSs, alone or combined in multimodal treatments, is of great interest and warrants further investigations.



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