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https://www.readbyqxmd.com/read/28643737/changes-in-pharyngeal-constrictor-volumes-during-head-and-neck-radiation-therapy-implications-for-dose-delivery
#1
Akila Kumarasiri, Chang Liu, Mona Kamal, Correen Fraser, Stephen Brown, Indrin J Chetty, Jinkoo Kim, Farzan Siddiqui
OBJECTIVE: The objective of this study was to evaluate the anatomical changes and associated dosimetric consequences to pharyngeal constrictor muscles (PCMs) that occur during head and neck (H and N) radiotherapy (RT). MATERIALS AND METHODS: A cohort of 13 oropharyngeal cancer patients with daily cone beam computed tomography (CBCT) was retrospectively studied. On every 5th CBCT image, PCM was manually delineated by a radiation oncologist. The anterior-posterior PCM thickness was measured at the midline level of C3 vertebral body...
April 2017: Journal of Cancer Research and Therapeutics
https://www.readbyqxmd.com/read/28641873/targeting-dna-repair-for-precision-radiotherapy-balancing-the-therapeutic-ratio
#2
REVIEW
Osman Mahamud, Jonathan So, Melvin L K Chua, Robert G Bristow
Genomic instability is underpinned by defects in the DNA damage response and DNA repair pathways. Subsequent clonal selection and adaption can lead to a mutator phenotype and tumor aggression. Importantly, tumor cell sensitivity to chemotherapy and radiotherapy can depend highly on the cellular capacity to repair DNA damage within and between tumor types. Annotation of functional defects in DNA damage response and DNA repair function may allow for the development of novel prognostic biomarkers. This information could also be used to predict therapeutic response, including predicting responses following inhibition of DNA repair...
April 25, 2017: Current Problems in Cancer
https://www.readbyqxmd.com/read/28638454/downregulation-of-mitochondrial-single-stranded-dna-binding-protein-ssbp1-induces-mitochondrial-dysfunction-and-increases-the-radiosensitivity-in-non-small-cell-lung-cancer-cells
#3
You Wang, Liu Hu, Ximei Zhang, Hong Zhao, Hui Xu, Yuehua Wei, Huangang Jiang, Conghua Xie, Yunfeng Zhou, Fuxiang Zhou
Radiotherapy is one of the major therapeutic strategies for human non-small cell lung cancer (NSCLC), but intrinsic radioresistance of cancer cells makes a further improvement of radiotherapy for NSCLC challenging. Mitochondrial function is frequently dysregulated in cancer cells for adaptation to the changes of tumor microenvironment after exposure to radiation. Therefore, targeting mitochondrial biogenesis and bioenergetics is an attractive strategy to sensitize cancer cells to radiation therapy. In this study, we found that downregulation of single-strand DNA-binding protein 1 (SSBP1) in H1299 cells was associated with inducing mitochondrial dysfunction and increasing radiosensitivity to ionizing radiation...
2017: Journal of Cancer
https://www.readbyqxmd.com/read/28636294/-selective-therapeutic-de-escalation-in-early-stage-breast-cancer
#4
Aikaterini Liapi, Apostolos Sarivalasis, Wendy Jeanneret Sozzi, Loïc Lelièvre, Khalil Zaman
The survival of patients with breast cancer has improved considerably thanks to adjuvant radiotherapy and systemic treatments. Due to the potential adverse events associated with these treatments, a de-escalation effort was undertaken concerning surgery and more recently the adjuvant treatments. Conservative breast surgery and the avoidance of axillary dissection were possible for the majority of the patients without detrimental effect on survival. New radiotherapy techniques and the consideration of cancer biology allowed to better protect the peripheral organs and even to avoid treatment in certain low-risk patients...
May 17, 2017: Revue Médicale Suisse
https://www.readbyqxmd.com/read/28633637/seroma-change-during-magnetic-resonance-imaging-guided-partial-breast-irradiation-and-its-clinical-implications
#5
Seung Hyuck Jeon, Kyung Hwan Shin, So-Yeon Park, Jung-In Kim, Jong Min Park, Jin Ho Kim, Eui Kyu Chie, Hong-Gyun Wu
BACKGROUND: To investigate the patterns of post-lumpectomy seroma volume (SV) change and related clinical factors to determine the benefits of adaptive planning in magnetic resonance imaging (MRI)-guided partial breast irradiation (PBI). METHODS: MRI data obtained from 37 women with early breast cancer acquired at simulation and at the 1st, 6th, and 10th fractions were analyzed. The planning target volume (PTV) was defined as unequal margins of 10-15 mm added according to the directional surgical margin status of each seroma...
June 20, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28617804/integrating-tenascin-c-protein-expression-and-1q25-copy-number-status-in-pediatric-intracranial-ependymoma-prognostication-a-new-model-for-risk-stratification
#6
Felipe Andreiuolo, Gwénaël Le Teuff, Mohamed Amine Bayar, John-Paul Kilday, Torsten Pietsch, André O von Bueren, Hendrik Witt, Andrey Korshunov, Piergiorgio Modena, Stefan M Pfister, Mélanie Pagès, David Castel, Felice Giangaspero, Leila Chimelli, Pascale Varlet, Stefan Rutkowski, Didier Frappaz, Maura Massimino, Richard Grundy, Jacques Grill
PURPOSE: Despite multimodal therapy, prognosis of pediatric intracranial ependymomas remains poor with a 5-year survival rate below 70% and frequent late deaths. EXPERIMENTAL DESIGN: This multicentric European study evaluated putative prognostic biomarkers. Tenascin-C (TNC) immunohistochemical expression and copy number status of 1q25 were retained for a pooled analysis of 5 independent cohorts. The prognostic value of TNC and 1q25 on the overall survival (OS) was assessed using a Cox model adjusted to age at diagnosis, tumor location, WHO grade, extent of resection, radiotherapy and stratified by cohort...
2017: PloS One
https://www.readbyqxmd.com/read/28610698/denoising-portal-images-by-minimizing-the-sure-estimator-on-a-parameterized-family-of-shrinkage-functions
#7
Antonio González-López, Pedro Campos-Morcillo
The number of verification portal images in radiotherapy has increased in the last years. On the other hand, radiation delivered during imaging is not confined to the treatment volumes, but also affects the surrounding organs and tissues. In order to reduce the overall radiation dose due to imaging, one approach would be to reduce the dose per image, but noise would increase and the quality of portal images would reduce. The limited quality of portal images makes it difficult to propose a reduction of dose if there is no way to effectively reduce noise...
June 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28592116/radionuclides-in-radiation-induced-bystander-effect-may-it-share-in-radionuclide-therapy
#8
M Widel
For many years in radiobiology and radiotherapy predominated the conviction that cellular DNA is the main target for ionizing radiation, however, the view has changed in the past 20 years. Nowadays, it is assumed that not only directed (targeted) radiation effect, but also an indirect (non-targeted) effect may contribute to the result of radiation treatment. Non-targeted effect is relatively well recognized after external beam irradiation in vitro and in vivo, and comprises such phenomena like radiation-induced bystander effect (RIBE), genomic instability, adaptive response and abscopal (out of field) effect...
June 8, 2017: Neoplasma
https://www.readbyqxmd.com/read/28590814/a-dosimetric-parameter-to-limit-chest-wall-toxicity-in-sabr-of-nsclc
#9
Raphaël Jumeau, Édith Filion, Houda Bahig, Toni Vu, Louise Lambert, David Roberge, Robert Doucet, Marie-Pierre Campeau
OBJECTIVE: Chest wall (CW) toxicity (rib fracture and/or pain) is a recognized complication of stereotactic ablative radiotherapy (SABR) for non-small cell lung cancer (NSCLC). The aim of this study was to evaluate the frequency of CW toxicity following SABR and to propose a new dosimetric parameter. METHODS: We reviewed the charts and SABR plans from patients treated for T1-T2N0 peripheral NSCLC between 2009 and 2015. The CW structure was created through a 3 cm expansion of the lung...
June 7, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28587761/itv-mid-ventilation-gating-or-couch-tracking-a-comparison-of-respiratory-motion-management-techniques-based-on-4d-dose-calculations
#10
Stefanie Ehrbar, Alexander Jöhl, Adrianna Tartas, Luisa Sabrina Stark, Oliver Riesterer, Stephan Klöck, Matthias Guckenberger, Stephanie Tanadini-Lang
PURPOSE: Respiratory motion-management techniques (MMT) aim to ensure tumor dose coverage while sparing lung tissue. Dynamic treatment-couch tracking of the moving tumor is a promising new MMT and was compared to the internal-target-volume (ITV) concept, the mid-ventilation (MidV) principle and the gating approach in a planning study based on 4D dose calculations. METHODS: For twenty patients with lung lesions, planning target volumes (PTV) were adapted to the MMT and stereotactic body radiotherapy treatments were prepared with the 65%-isodose enclosing the PTV...
June 3, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28585491/a-simple-method-for-2-d-in-vivo-dosimetry-by-portal-imaging
#11
Stefano Peca, Derek Wilson Brown, Wendy Lani Smith
PURPOSE: To improve patient safety and treatment quality, verification of dose delivery in radiotherapy is desirable. We present a simple, easy-to-implement, open-source method for in vivo planar dosimetry of conformal radiotherapy by electronic portal imaging device (EPID). METHODS: Correlation ratios, which relate dose in the mid-depth of slab phantoms to transit EPID signal, were determined for multiple phantom thicknesses and field sizes. Off-axis dose is corrected for by means of model-based convolution...
January 1, 2017: Technology in Cancer Research & Treatment
https://www.readbyqxmd.com/read/28585490/in-vivo-portal-imaging-dosimetry-identifies-delivery-errors-in-rectal-cancer-radiotherapy-on-the-belly-board-device
#12
Stefano Peca, Richie Siddhartha Sinha, Derek Wilson Brown, Wendy Lani Smith
PURPOSE: We recently developed a novel, open-source in vivo dosimetry that uses the electronic portal imaging device to detect dose delivery discrepancies. We applied our method on patients with rectal cancer treated on a belly board device. METHODS: In vivo dosimetry was performed on 10 patients with rectal cancer treated prone on the belly board with a 4-field box arrangement. Portal images were acquired approximately once per week from each treatment beam. Our dosimetry method used these images along with the planning CT to reconstruct patient planar dose at isocenter depth...
January 1, 2017: Technology in Cancer Research & Treatment
https://www.readbyqxmd.com/read/28560404/intermittent-low-dose-irradiation-enhances-the-effectiveness-of-radio-and-chemo-therapy-for-human-colorectal-adenocarcinoma-cell-line-ht-29
#13
Yang Wang, Yezhou Li, Li Yang, Dexin Yin
Low dose irradiation (LDIR) induces hormesis and adaptive response in organism and mammalian cell lines. Notably, LDIR generates distinct biological effects in cancer cells from normal cells, e.g., it may affect the growth of cancer cells via the activation of certain cell signaling pathway, which does not exist in normal cells. Therefore, LDIR is considered as a promising assistant method of clinical cancer therapy. In this study, we chose human colorectal adenocarcinoma cell line HT-29 as the experimental model, and investigated the differential biological effects between 250 mGy single dose LDIR and 250 mGy intermittent LDIR pretreatments in high dose irradiation (HDIR) radiotherapy and 5-fluorouracil (5-FU) based chemotherapy...
May 30, 2017: Oncology Reports
https://www.readbyqxmd.com/read/28559146/translation-and-adaptation-of-the-radiotherapy-edema-rating-scale-to-brazilian-portuguese
#14
Débora Dos Santos Queija, Lica Arakawa-Sugueno, Bruna Mello Chamma, Marco Aurélio Vamondes Kulcsar, Rogério Aparecido Dedivitis
INTRODUCTION: Internal lymphedema is one of the sequelae of head and neck cancer treatment that can lead to varying degrees of swallowing, speech, and respiration alterations. The Radiotherapy Edema Rating Scale, developed by Patterson et al., is a tool used to evaluate pharyngeal and laryngeal edema. OBJECTIVE: To translate into Brazilian Portuguese, to culturally adapt and test this scale in patients undergoing treatment for head and neck cancer. METHODS: The process followed the international guidelines and translation steps by two head and neck surgeons and back-translation performed independently by two North-American natives...
May 9, 2017: Brazilian Journal of Otorhinolaryngology
https://www.readbyqxmd.com/read/28549631/les-traitements-combin%C3%A3-s-dans-les-formes-%C3%A3-haut-risque-%C3%A3-volutif-du-cancer-de-la-prostate-localis%C3%A3-ou-non
#15
Laurie Monnier, Stéphane Culine, Luc Cormier
The high-risk group of prostate cancers is a heterogeneous group. A better definition of the criteria could bring a better selection of patients' selection in the combined local treatment or even in the general treatment. A treatment of these forms is the hormonoradiotherapy. The modalities of the radiotherapy and the hormonotherapy are to be defined and to be adapted according to prognostic factors of these patients. The surgery is also a possible treatment under certain conditions of selection of the patients and the adaptation of the surgical techniques...
May 23, 2017: La Presse Médicale
https://www.readbyqxmd.com/read/28547820/future-of-medical-physics-real-time-mri-guided-proton-therapy
#16
Bradley M Oborn, Stephen Dowdell, Peter E Metcalfe, Stuart Crozier, Radhe Mohan, Paul J Keall
With the recent clinical implementation of real-time MRI guided x-ray beam therapy (MRXT), attention is therapy (MRPT). MRI guidance for proton beam therapy is expected to offer a compelling improvement to the turning to the concept of combining real-time MRI guidance with proton beam therapy; MRI guided proton beam current treatment workflow which is warranted arguably more than for x-ray beam therapy. This argument is born out of the fact that proton therapy toxicity outcomes are similar to that of the most advanced IMRT treatments, despite being a fundamentally superior particle for cancer treatment...
May 26, 2017: Medical Physics
https://www.readbyqxmd.com/read/28543069/real-time-dynamic-mr-image-reconstruction-using-compressed-sensing-and-principal-component-analysis-cs-pca-demonstration-in-lung-tumor-tracking
#17
Bryson Dietz, Eugene Yip, Jihyun Yun, B Gino Fallone, Keith Wachowicz
PURPOSE: This work presents a real-time dynamic image reconstruction technique, that combines compressed sensing and principal component analysis (CS-PCA), to achieve real-time adaptive radiotherapy with the use of a linac-magnetic resonance imaging system. METHODS: Six retrospective fully sampled dynamic data sets of patients diagnosed with non-small cell lung cancer were used to investigate the CS-PCA algorithm. Using a database of fully sampled k-space, principal components (PC's) were calculated to aid in the reconstruction of undersampled images...
May 19, 2017: Medical Physics
https://www.readbyqxmd.com/read/28533809/brachytherapy-in-the-treatment-of-bile-duct-cancer-a-tough-challenge
#18
REVIEW
Janusz Skowronek, Grzegorz Zwierzchowski
The majority of patients with bile duct cancer are diagnosed with clinically advanced disease. Most of these patients have a short life expectancy and are treated with palliative aim. Most patients present with locally advanced or metastatic disease, which is not amenable to surgical resection, resulting in poor survival. Adjuvant or definitive radiotherapy, with or without chemotherapy, is therefore used in many centers worldwide for better local control, and with the expectation that it will have a favorable effect on survival...
April 2017: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/28533222/fractionated-radiation-therapy-stimulates-anti-tumor-immunity-mediated-by-both-resident-and-infiltrating-polyclonal-t-cell-populations-when-combined-with-pd1-blockade
#19
Simon J Dovedi, Eleanor J Cheadle, Amy Popple, Edmund Poon, Michelle Morrow, Ross Stewart, Erik Yusko, Catherine Sanders, Marissa Vignali, Ryan Emerson, Harlan Robins, Robert W Wilkinson, Jamie Honeychurch, Timothy Illidge
Purpose: Radiotherapy (RT) is a highly effective anti-cancer treatment forming part of the standard of care for the majority of patients, but local and distal disease recurrence remains a major cause of mortality. RT is known to enhance tumor immunogenicity; however, the contribution and mechanisms of RT induced immune responses are unknown. <p>Experimental Design: The impact of low-dose fractionated RT (5 x 2 Gy) alone and in combination with αPD-1 mAb on the tumor microenvironment was evaluated by flow cytometry and next-generation sequencing (NGS) of the T-cell receptor (TCR)-repertoire...
May 22, 2017: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
https://www.readbyqxmd.com/read/28506589/the-relationship-between-dosimetric-factors-side-effects-and-survival-in-patients-with-non-small-cell-lung-cancer-treated-with-definitive-radiotherapy
#20
Dilruba Okumus, Sureyya Sarihan, Sema Gozcu, Deniz Sigirli
The patients with non-small cell lung cancer (NSCLC) treated with definitive conformal radiotherapy (RT) were evaluated in terms of side effects and survival. Normal tissue complication probability (NTCP) was calculated for 68 patients treated between 2009 and 2012. Clinical and dosimetric factors were analyzed. The median dose of 63 Gy (range: 54 to 70 Gy) was given with conformal RT with blocks (n = 37), 3-dimensional conformal RT (3DCRT) (n = 11), or intensity-modulated RT (IMRT) (n = 20)...
May 12, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
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