687 research outputs found
Interacting six-dimensional topological field theories
We study the gauge-fixing and symmetries (BRST-invariance and vector
supersymmetry) of various six-dimensional topological models involving Abelian
or non-Abelian 2-form potentials.Comment: 11 page
Combined radio- and chemotherapy for non-small cell lung cancer: systematic review of landmark studies based on acquired citations
The important role of combined chemoradiation for several groups of patients with nonsmall
cell lung cancer (NSCLC) is reflected by the large number of scientific articles
published during the last 30 years. Different measures of impact and clinical relevance of
published research are available, each with its own pros and cons. For this review, article
citation rate was chosen. Highly cited articles were identified through systematic search
of the citation database Scopus. Among the 100 most often cited articles, meta-analyses
(nD5) achieved a median of 203 citations, guidelines (nD7) 97, phase III trials (nD29) 168,
phase II trials (nD21) 135, phase I trials (nD7) 88, and others combined 115.5 (p D0.001).
Numerous national and international cooperative groups and several single institutions
were actively involved in performing often cited, high-impact trials, reflecting the fact that
NSCLC is a world-wide challenge that requires research collaboration. Platinum-containing
combinations have evolved into a standard of care, typically administered concurrently.The
issue of radiotherapy fractionation and total dose has also been studied extensively, yet
with less conclusive results. Differences in target volume definition have been addressed.
However, it was not possible to test all theoretically possible combinations of radiotherapy
regimens, drugs, and drug doses (lower radiosensitizing doses compared to higher systemically
active doses).That is why current guidelines offer physicians a choice of different,
presumably equivalent treatment alternatives. This review identifies open questions and
strategies for further research
Prospective randomized clinical studies involving reirradiation: update of a systematic review
Background Reirradiation is a potentially useful option for many patients with recurrent cancer, aiming at cure or
symptom palliation, depending on disease/recurrence type and stage. The purpose of this follow-up study to a previous
review from 2016 was to summarize all recently published randomized trials. Points of interest again included identifcation
of methodological strengths and weaknesses, practice-changing results, and open questions.
Material and methods Systematic review of trials published between 2015 and February 2023.
Results We reviewed 7 additional trials, most of which addressed reirradiation of head and neck or brain tumours. The
median number of patients was 60. Mirroring the previous review, trial design, primary endpoints and statistical hypotheses
varied widely. The updated results only impact on decision making for reirradiation of nasopharynx cancer and glioma.
Patients with one of these diseases, as well as other head and neck cancers, may benefit from reirradiation-induced local
control, e.g. in terms of progression-free survival. For the first time, hyperfractionated radiotherapy emerged as preferred
option for recurrent, inoperable nasopharynx cancer. Despite better therapeutic ratio with hyperfractionation, serious toxicity
remains a concern after high cumulative total doses. Randomized trials are still lacking for prostate cancer and other sites.
Conclusion Multicentric randomized trials on reirradiation are feasible and continue to refine the current standard of care
for recurrent disease after previous radiotherapy. Ongoing prospective studies such as the European Society for Radiotherapy
and Oncology and European Organisation for Research and Treatment of Cancer (ESTRO-EORTC) observational cohort
ReCare (NCT: NCT03818503) will further shape the clinical practice of reirradiation
Prospective randomized clinical studies involving reirradiation: update of a systematic review
BACKGROUND
Reirradiation is a potentially useful option for many patients with recurrent cancer, aiming at cure or symptom palliation, depending on disease/recurrence type and stage. The purpose of this follow-up study to a previous review from 2016 was to summarize all recently published randomized trials. Points of interest again included identifcation of methodological strengths and weaknesses, practice-changing results, and open questions.
MATERIAL AND METHODS
Systematic review of trials published between 2015 and February 2023.
RESULTS
We reviewed 7 additional trials, most of which addressed reirradiation of head and neck or brain tumours. The median number of patients was 60. Mirroring the previous review, trial design, primary endpoints and statistical hypotheses varied widely. The updated results only impact on decision making for reirradiation of nasopharynx cancer and glioma. Patients with one of these diseases, as well as other head and neck cancers, may benefit from reirradiation-induced local control, e.g. in terms of progression-free survival. For the first time, hyperfractionated radiotherapy emerged as preferred option for recurrent, inoperable nasopharynx cancer. Despite better therapeutic ratio with hyperfractionation, serious toxicity remains a concern after high cumulative total doses. Randomized trials are still lacking for prostate cancer and other sites.
CONCLUSION
Multicentric randomized trials on reirradiation are feasible and continue to refine the current standard of care for recurrent disease after previous radiotherapy. Ongoing prospective studies such as the European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer (ESTRO-EORTC) observational cohort ReCare (NCT: NCT03818503) will further shape the clinical practice of reirradiation
Personalized treatment of brain metastases: Evolving survival prediction models may benefit from evaluation of serum tumor markers (narrative review)
Treatment of a limited number of brain metastases (oligometastases) might include complex and sometimes invasive approaches, e.g. neurosurgical resection followed by post-operative stereotactic radiotherapy, and thus, correct identification of patients who are appropriate candidates is crucial. Both, staging procedures that visualize the true number of metastastic lesions and prognostic assessments that identify patients with limited survival, who should be managed with less complex, palliative approaches, are necessary before proceeding with local treatment that aims at eradication of all oligometastases. Some of the prognostic models, e.g. the LabBM score (laboratory parameters in patients with brain metastases), include blood biomarkers believed to represent surrogate markers of disease extent. In a recent study, patients with oligometastases and a LabBM score of 0 (no abnormal biomarkers) had an actuarial 5-year survival rate of 27% after neurosurgical resection and 39% after stereotactic radiotherapy. Other studies have tied serum tumor markers such as carcinoembryonic antigen (CEA) to survival outcomes. Even if head-to-head comparisons and large-scale definitive analyses are lacking, the available data suggest that attempts to integrate tumor marker levels in blood biomarker-based survival prediction models are warranted
Personalized treatment of brain metastases: Evolving survival prediction models may benefit from evaluation of serum tumor markers (narrative review)
Treatment of a limited number of brain metastases (oligometastases) might include complex and sometimes invasive approaches, e.g. neurosurgical resection followed by post-operative stereotactic radiotherapy, and thus, correct identification of patients who are appropriate candidates is crucial. Both, staging procedures that visualize the true number of metastastic lesions and prognostic assessments that identify patients with limited survival, who should be managed with less complex, palliative approaches, are necessary before proceeding with local treatment that aims at eradication of all oligometastases. Some of the prognostic models, e.g. the LabBM score (laboratory parameters in patients with brain metastases), include blood biomarkers believed to represent surrogate markers of disease extent. In a recent study, patients with oligometastases and a LabBM score of 0 (no abnormal biomarkers) had an actuarial 5-year survival rate of 27% after neurosurgical resection and 39% after stereotactic radiotherapy. Other studies have tied serum tumor markers such as carcinoembryonic antigen (CEA) to survival outcomes. Even if head-to-head comparisons and large-scale definitive analyses are lacking, the available data suggest that attempts to integrate tumor marker levels in blood biomarker-based survival prediction models are warranted.
Keywords: biomarkers; brain metastases; prognostic model; score; tumor marker
How we treat octogenarians with brain metastases
Biologically younger, fully independent octogenarians are able to tolerate most oncological treatments. Increasing frailty results in decreasing eligibility for certain treatments, e.g., chemotherapy and surgery. Most brain metastases are not an isolated problem, but part of widespread cancer dissemination, often in combination with compromised performance status. Multidisciplinary assessment is key in this vulnerable patient population where age, frailty, comorbidity and even moderate additional deficits from brain metastases or their treatment may result in immobilization, hospitalization, need for nursing home care, termination of systemic anticancer treatment etc. Here, we provide examples of successful treatment (surgery, radiosurgery, systemic therapy) and best supportive care, and comment on the limitations of prognostic scores, which often were developed in all-comers rather than octogenarians. Despite selection bias in retrospective studies, survival after radiosurgery was more encouraging than after whole-brain radiotherapy. Prospective research with focus on octogenarians is warranted to optimize outcomes
Personalized radiotherapy of brain metastases: survival prediction by means of dichotomized or differentiated blood test results?
Background and objectives: The validated LabBM score (laboratory parameters in patients with brain metastases) represents a widely applicable survival prediction model, which incorporates 5 blood test results (serum lactate dehydrogenase (LDH), C-reactive protein (CRP), albumin, platelets and hemoglobin). All tests are classified as normal or abnormal, without accounting for the wide range of abnormality observed in practice. We tested the hypothesis that improved stratification might be possible, if more granular test results are employed.
Methods: Retrospective analysis of 198 patients managed with primary whole-brain radiotherapy in one of the institutions who validated the original LabBM score.
Results: For two blood tests (albumin, CRP), discrimination was best for the original dichotomized version (normal/abnormal). For two others (LDH, hemoglobin), a three-tiered classification was best. The number of patients with low platelet count was not large enough for detailed analyses. A modified LabBM score was developed, which separates the intermediate of originally 3 prognostic groups into 2 statistically significantly different strata, resulting in a 4-tiered score.
Conclusion: This initial proof-of-principle study suggests that granular blood test results might contribute to further improvement of the score, or alternatively development of a nomogram, if additional large-scale studies confirm the encouraging results of the present analysis
AdS(3) Solutions of IIB Supergravity from D3-branes
We consider pure D3-brane configurations of IIB string theory which lead to
supersymmetric solutions containing an AdS factor. They can provide new
examples of AdS/CFT examples on D3-branes whose worldvolume is
partially compactified. When the internal 7 dimensional space is non-compact,
they can be identified as supersymmetric fluctuations of higher dimensional AdS
solutions and are in general dual to 1/8-BPS operators thereof. We find that
supersymmetry requires the 7 dimensional space take the form of a warped U(1)
fibration over a 6 dimensional Kahler manifold.Comment: 10 pages, no figure, JHEP3.cls; v3: corrected errors in the published
versio
Gravitational F-terms of N=1 Supersymmetric SU(N) Gauge Theories
We use the generalized Konishi anomaly equations and R-symmetry anomaly to
compute the exact perturbative and non-perturbative gravitational F-terms of
four-dimensional N=1 supersymmetric gauge theories. We formulate the general
procedure for computation and consider chiral and non-chiral SU(N) gauge
theories.Comment: 25 pages, v2: minor changes in section 4, references adde
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