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Objective:To investigate the value of nomograms based on clinical parameters, apparent diffusion coefficient (ADC) and MRI-derived radiomics in predicting survival of patients with locally advanced cervical cancer (LACC) after concurrent chemoradiotherapy (CCRT).Methods:Clinical data of 423 patients with IB-IVA cervical cancer treated with CCRT at Anhui Provincial Hospital Affiliated to Anhui Medical University from March 2014 to March 2020 were retrospectively analyzed and randomly divided into the training and validation groups at a ratio of 2∶1 using the simple randomization method. The values of ADC min, ADC mean, ADC max and 3D texture parameters of diffusion weighted imaging (DWI), T 2WI, T 2WI-fat suppression of pre-treatment primary lesions in all patients were measured. The least absolute shrinkage and selection operator (LASSO) algorithm and logistic regression analysis were used to screen the texture features and calculate radiomics score (Rad-score). Cox regression analysis was employed to construct nomogram models for predicting overall survival (OS) and cancer-specific survival (CS) of patients with LACC after CCRT, which were subject to internal and external validation. Results:Squamous cell carcinoma antigen (SCC-Ag), external beam radiotherapy dose, ADCmin and Rad-score were the independent prognostic factors for OS and CS of LACC patients after CCRT and constituted predictive models for OS and CS. The area under the receiver operating characteristic (ROC) curve (AUC) of two models in predicting 1-year, 3-year, 5-year OS and CS was 0.906, 0.917, 0.916 and 0.911, 0.918, 0.920, with internally validated consistency indexes (C-indexes) of 0.897 and 0.900. Then, models were brought into the validation group for external validation with AUC of 0.986, 0.942, 0.932 and 0.986, 0.933, 0.926 in predicting 1-year, 3-year, 5-year OS and CS.Conclusion:The nomograms based on clinical parameters, ADC values and MRI-derived radiomics are of high clinical value in predicting OS and CS of patients with LACC after CCRT, which can be used as prognostic markers for patients with cervical cancer to certain extent.
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Acute radiation dermatitis (ARD) is one of the most common toxicities of radiotherapy. Currently, there is still no standardised protocol and guideline on the prevention and treatment of ARD. Photobiomodulation therapy (PBMT) has the functions of stimulating wound healing, reducing inflammatory reaction and mitigating pain, etc. Consequently, recent research progress at home and abroad in the application of PBMT for the prevention and treatment of acute radiation skin reactions was reviewed, aiming to provide reference for clinical application of PBMT in radiation protection.
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Objective:To propose a deep learning network model 2D-PE-GAN to automatically delineate the target area of nasopharyngeal carcinoma and improve the efficiency of target area delineation.Methods:The model adopted the architecture of generative adversarial networks which used a UNet similar structure as the generator, and 2D-PE-block was added after each layer of convolution operation of the generator to improve the accuracy of delineation. The experimental data included CT images from 130 cases of nasopharyngeal carcinoma. The images were preprocessed before model training. In addition, three models of UNet, GAN, and GAN with an attention mechanism were compared, and Dice similarity coefficient, Hausdorff distance, accuracy, Matthews correlation coefficient, Jaccard distance were employed to evaluate network performance.Results:Compared with UNet, GAN and GAN with the attention mechanism, the average Dice similarity coefficient of 2D-PE-GAN network segmentation of CTV was increased by 26%, 4% and 2%. The average Dice similarity coefficient of GTV segmentation was increased by 21%, 4%, 2%, respectively. Compared with the GAN network with the attention mechanism, the parameters and time of 2D-PE-GAN were reduced by 0.16% and 18%, respectively.Conclusions:Compared with the above three networks, 2D-PE-GAN network can increase the segmentation accuracy of nasopharyngeal carcinoma target area delineation. At the same time, compared with the attention mechanism with similar reasons, 2D-PE-GAN network can reduce the occupation of computing resources when the segmentation accuracy is not much different.
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Objective:To investigate the value of nomogram based on intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) and MRI-derived radiomics for predicting recurrence after concurrent chemoradiotherapy (CCRT) in patients with locally advanced cervical cancer (LACC).Methods:Clinical data of 111 patients with ⅠB-ⅣA cervical cancer who underwent CCRT at Anhui Provincial Hospital from December 2014 to December 2019 and were continuously followed up were retrospectively analyzed. Pre-treatment IVIM-DWI parameters (ADC, D, D * and f) and pre- and post-treatment 3D texture parameters (from axial T 2WI) of the primary lesions were measured. Least absolute shrinkage and selection operator (LASSO) algorithm and multivariate logistic regression analysis were used to filter texture features and calculate radiomics score (Rad-score). A Cox regression model was used to analyze independent risk factors for recurrence after CCRT in patients with LACC and construct a nomogram. Results:External beam radiotherapy dose, f value , pre-treatment Rad-score and post-treatment Rad-score ( HR=0.204, 3.253, 2.544, 7.576) were the independent prognostic factors for recurrence after CCRT in cervical cancer patients and jointly formed the nomogram. The area under curve (AUC) of the nomogram for predicting 1-, 3- and 5-year disease-free survival (DFS) was 0.895, 0.888 and 0.916, with internal validation C-indexes of 0.859, 0.903 and 0.867, respectively. The decision curves analysis showed that the nomogram has a higher net clinical benefit compared to other models, and the clinical impact curves further visualized its predictive accuracy. Conclusions:The nomogam based on IVIM-DWI and radiomics has high clinical value in predicting recurrence after CCRT in patients with LACC, providing reference for prognostic assessment and individualized treatment of cervical cancer patients.
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Objective:To evaluate the effect of upregulation of HuR gene on the radiosensitivity of esophageal squamous cell carcinoma cell Kyse450. Methods:The HuR gene of Kyse450 cells was upregulated by lentivirus. At the same time, X-ray irradiation at a dose of 6 Gy was selected as the intervention condition. Western blot and qPCR were used to detect the expression levels of protein and RNA after Kyse450 transfection, respectively. CCK8 kit was employed to determine the cell proliferation rate. Clone formation assay was adopted to evaluate the ability of cell clone formation. Wound healing experiment and the Transwell test were performed to detect changes in cell migration. Results:CCK8 assay showed that the proliferation ability of cells was enhanced after upregulation of HuR gene, and this enhancement trend was more obvious after radiation. The plate cloning experiment showed that with the increase of radiation dose, the clone formation rates were decreased in both groups, but the clone formation rate in the overexpression group was higher than that in the control group. Wound healing experiment and Transwell test demonstrated that the wound healing rate and migration ability in the overexpression group were higher than those in the control group, and the difference was more significant after radiotherapy. Western blot showed that the levels of MMP9 and MMP2 at 24 h after radiotherapy in the overexpression group were higher than those in the control group. Conclusion:The upregulation of HuR can enhance the proliferation, cloning, migration capabilities and decrease the radiosensitivity of esophageal squamous cell carcinoma cells.
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Objective:To evaluate the impacts of tissue heterogeneity on dose calculation of cervical brachytherapy by comparing the doses calculated by two clinically used dose calculation method and the CT image-based Monte Carlo (MC) method.Methods:This study retrospectively selected 11 patients with cervical cancer treated with 3D brachytherapy in Anhui Provincial Cancer Hospital from January 2018 to June 2020. The dose distribution of each plan was calculated via three methods, dose calculation method described in American Association of Physicist in Medicine(AAPM) Task Group No. 43 Report (TG43-BT), Acuros BV(BV-BT) used to perform accurate dose calculations in high-dose-rate (HDR) brachytherapy with phantom heterogeneity, and CT image-based EGSnrc tool kit used to perform Monte Carlosimulation (MC-BT). The dose volumes( V3 Gy, V6 Gy, V9 Gy, and V12 Gy), target volume doses( D98, D90, D50), D2 cm 3 of organs at risk (OARs) calculated by the three methods were compared. Results:The HRCTV D90obtained by TG43-BT was 6.274 Gy, which was even overestimated by around 5% compared to the result calculated by MC-BT. Meanwhile, TG43-BT overestimated the dose volumesand the target volume doses compared to MC-BT.Except for D50 and V12 Gy, the differences between the doses to tumor calculated by BV-BT and MC-BT were not statistically significant( P>0.05). There was also no significant statistical difference between the D2 cm 3 of rectum, small intestine, and sigmoid calculated by BV-BT and MC-BT ( P>0.05). In contrast, the dose to D2 cm 3 of bladder determined by MC-BT was 4.609 Gy, which was notably higher than those deter mined by TG43-BT and BV-BT. Conclusions:TG43-BT overestimated the doses to tumor targets and most OARs since the effects of tissue heterogeneity were not taken into consideration. BV-BT performed efficient calculation and most of the dose distributionin target volume and OARs obtained by BV-BT were consistent with that calculated by MC-BT. Nevertheless, low accuracy occurred for the regions near the sources and full bladder, which warrants further caution in clinical evaluation.
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Objective:To investigate the impacts of the composition and physical density of tissue on the dose distribution of implanted 125I seeds, in order to provide references for the clinical dose calculation and assessment of implanted radioactive particles. Methods:The OncoSeed 6711 physical model of 125I seeds was established using thes of twareegs_brachy and was validated through the calculation of dose rate constant and the radial dose function [ g( r)] in water. Then, based on the element composition and physical density of different types of tissue, the g( r) and absorbed dose ratein water, prostate, breast, muscle, and bone were calculated. Results:The calculated dose rate constant (0.950 cGy·h -1·U -1) and g( r)in water approached the values in related literature. The absorbed dose in bone was 6.042 times than that in water at a distance of 0.05 cm from the implanted source. The difference between the absorbed doses in breast and water was more than 10% at a distance of less than 1.7 cm from the implanted source. The difference between the absorbed doses in prostate/muscle and water was less than 5% at the same radial location. Conclusions:The dose distribution of 125I seeds in some types of human tissue is significantly different from that in water, which should be carefully considered in clinical dose calculation.
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Objective:To investigate the value of quantitative CT (QCT) body component parameters before and after transcatheter arterial chemoembolization (TACE) as prognostic indicator for patients with hepatic cell carcinoma (HCC).Methods:Retrospective analysis was performed on 40 patients with advanced HCC who received TACE treatment in Anhui Provincial Hospital Affiliated to Anhui Medical University from November 2013 to May 2017, all of them received QCT scanning before and after treatment. The information were recorded, including gender, age, alpha-fetoprotein (AFP), TNM stage, liver function Child-Pugh grade, portal venous thromboembolism, cirrhosis, maximum tumor diameter, tumor type, and frequency of interventional therapy. QCT parameters were measured before and after treatment, including L1, L2 bone mineral density (BMD), L3-level paravertebral muscle area (MA), subcutaneous fat area (SFA) and visceral fat area (VFA), and the change rate of QCT parameters (ΔBMD, ΔMA, ΔSFA, ΔVFA) before and after TACE were calculated after the QCT scan interval was standardized. The cut-off values of ΔBMD, ΔMA, ΔSFA and ΔVFA to diagnose the prognosis of HCC patients after TACE were obtained by drawing the ROC curves. The Kaplan-Meier method was used to calculate the survival rate, the Log-rank method was used for univariate analysis, and the Cox regression analysis model was used for multivariate analysis to screen out independent factors affecting the prognosis of HCC patients after TACE.Results:ROC curve analysis showed that the cut-off values of ΔBMD, ΔMA, ΔSFA and ΔVFA to diagnose the prognosis of HCC patients after TACE were -8.64%, -6.84%, -9.84% and 5.70%, respectively. Univariate analysis showed that AFP, TNM stage, liver function Child-Pugh grade, portal venous thrombosis, tumor type and ΔMA, ΔSFA, ΔVFA had statistically significant effects on prognosis ( P<0.1). Multivariate analysis showed that ΔMA, ΔVFA and portal venous thromboembolism were independent influencing factors for the prognosis of HCC patients after TACE treatment ( P<0.05). Conclusions:ΔMA, ΔVFA and portal venous thromboembolism have reference value for prognosis assessment of TACE treatment for HCC patients, and QCT body composition analysis is helpful to evaluate the prognosis of HCC patients.
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Acute radiation dermatitis is one of the most common toxicities of radiotherapy in patients with nasopharyngeal carcinoma. It leads to a series of symptoms such as erythema, desquamation and necrosis, which severely affect the quality of life. No concensus has been achieved on the standard prevention and treatment. In this article, literature review was performed in the prevention and treatment of acute radiation dermatitis in patients with nasopharyngeal carcinoma and relevant problems and prospects were proposed, aiming to provide certain reference for clinical trial and scientific research.
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Objective:To develop a deep learning model for predicting three-dimensional (3D) voxel-wise dose distributions for intensity-modulated radiotherapy (IMRT).Methods:A total of 110 postoperative rectal cancer cases treated by IMRT were considered in the study, of which 90 cases were randomly selected as the training-validating set and the remaining as the testing set. A 3D deep learning model named 3D U-Res-Net was constructed to predict 3D dose distributions. Three types of 3D matrices from CT images, structure sets and beam configurations were fed into the independent input channel, respectively, and the 3D matrix of IMRT dose distributions was taken as the output to train the 3D model. The obtained 3D model was used to predict new 3D dose distributions. The predicted accuracy was evaluated in two aspects: the average dose prediction bias and mean absolute errors (MAEs)of all voxels within the body, the dice similarity coefficients (DSCs), Hausdorff distance(HD 95) and mean surface distance (MSD) of different isodose surfaces were used to address the spatial correspondence between predicted and clinical delivered 3D dose distributions; the dosimetric index (DI) including homogeneity index, conformity index, V50, V45 for PTV and OARs between predicted and clinical truth were statistically analyzed with the paired-samples t test. Results:For the 20 testing cases, the average prediction bias ranged from -2.12% to 2.88%, and the MAEs varied from 2.55% to 5.75%. The DSCs value was above 0.9 for all isodose surfaces, the average MSD ranged from 0.21 cm to 0.45 cm, and the average HD 95 varied from 0.61 cm to 1.54 cm. There was no statistically significant difference for all DIs, except for bladder Dmean. Conclusions:This study developed a deep learning model based on 3D U-Res-Net by considering beam configurations input and achieved an accurate 3D voxel-wise dose prediction for rectal cancer treated by IMRT.
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Objective:To evaluate the application value of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) and dynamic contrast enhancement MRI (DCE-MRI) in the prediction of the early efficacy of concurrent chemoradiotherapy (CCRT) for cervical squamous cell carcinoma.Methods:Fifty patients with cervical squamous cell carcinoma confirmed by pathology were included. Before CCRT, IVIM-DWI and DCE-MRI were scanned, and the values of quantitative parameters including ADC, D, D * and f of IVIM-DWI and K trans, K ep, V e and V p of DCE-MRI before treatment were measured for all patients. MRI reexamination was performed 1 month after the end of CCRT, and all patients were divided into the cure group and the residual group according to the tumor remission. The parameters of IVIM-DWI and DCE-MRI before treatment were statistically compared between two groups. The optimal predictive parameters and predictive thresholds were determined by drawing the receiver operating characteristic (ROC) curve. Results:Twenty-four patients were assigned into the cure group and twenty-six patients in the residual group. The ADC, D and V e values before treatment in the cure group were significantly lower than those in the residual group (all P<0.05), whereas the f and K trans values were significantly higher than those in the residual group (both P<0.05). The other parameters did not significantly differ between two groups (all P>0.05). The area under ROC curve (AUC=0.823) of D value was the largest, followed by K transvalue (AUC=0.754). The combined prediction efficacy of D and K trans (AUC=0.867) was higher than that of either D or K trans alone. The sensitivity was 88.5%, 85.8% and 88.8%, and the specificity was 70.8%, 66.7% and 79.2%, respectively. Conclusions:Quantitative parameters of IVIM-DWI and DCE-MRI before treatment have certain predictive value for the early efficacy of CCRT in cervical squamous cell carcinoma, among which the predictive efficacy of D value is the highest, and the combined application of D and K trans can improve the predictive efficacy.
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Objective To evaluate the feasibility of utilizing dose-volume histogram (DVH) prediction models of organs at risk (OARs) to deliver automatic treatment planning of prostate cancer.Methods The training set included 30 cases randomly selected from a database of 42 cases of prostate cancer receiving treatment planning.The bladder and rectum were divided into sub-volumes (Ai) of 3 mm in layer thickness according to the spatial distance from the boundary of planning target volume (PTV).A skewed normal Gaussian function was adopted to fit the differential DVH of Ai,and a precise mathematical model was built after optimization.Using the embedded C++ subroutine of Pinnacle scripa,ahe volume of each Ai of the remaining validation set for 12 patients was obtained to predict the DVH parameters of these OARa,ahich were used as the objective functions to create personalized Pinnacle script.Finalla,automatic plans were generated using the script.The dosimetric differences among the original clinical plannina,aredicted value and the automatic treatment planning were statistically compared with paired t-test.Results DVH residual analysis demonstrated that predictive volume fraction of the bladder and rectum above 6 000 cGy were lower than those of the original clinical planning.The automatic treatment planning significantly reduced the V70,V60,V50 of the bladder and the V70 and V60 of the rectum than the original clinical planning (all P<0.05),the coverage and conformal index (CI) of PTV remained unchangea,and the homogeneity index (HI) was slightly decreased with no statistical significance (P> 0.05).Conclusion The automatic treatment planning of the prostate cancer based on the DVH prediction models can reduce the irradiation dose of OARs and improve the treatment planning efficiency.
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Objective To study the dosimetric parameters of Varian GammaMed Plus HDR 192 Ir source via Monte Carlo ( MC ) method based on the recommendation of the American Association of Physicist in Medicine ( AAPM) and European Society for Radiotherapy and Oncology ( ESTRO) . Methods Using the Monte Carlo program EGSnrc, an accurate model of 192 Ir source for MC calculations was establish firstly. Through formula derivation, bilinear interpolation and unit conversion, the air kerma strength per unit source activity, the dose rate constant, radial dose function and anisotropy function was obtained then , and compare the result with those in other published studies. Results The air kerma strength per unit source activity was 9. 781 × 10-8 U/Bq. The dose rate constant was 1. 113 cGy · h-1 · U-1 , with a discrepancy of less than 0. 4% compared with result published in other works. Furthermore, the curves of radial dose function and anisotropy function overall agree with the data shown in the literature. Conclusions The feasibility of performing dosimetric studies of 192 Ir source using the MC software EGSnrc was demonstrated. This work provides a theoretical guidance on analysis of the dose distribution of brachytherapy and on evaluation of the dose accuracy of clinical radiotherapy.
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Objective To evaluate the prognostic value of anemia in patients diagnosed with extranodal nasal-type natural killer (NK)/T cell lymphoma (NKTCL).Methods Clinical data of 1 225 NKTCL patients receiving the first course of treatment from 10 medical institutions in China were retrospectively analyzed.According to the diagnostic criteria in China,anemia was defined as the hemoglobin (Hb) level< 120 g/L for the male and< 110 g/L for the female from the sea-level area.The severity of anemia was classified into the extremely severe anemia (Hb ≤ 30 g/L),severe anemia (31-60 g/L),moderate anemia (61-90 g/L) and mild anemia (>90 g/L).Results Among 1 225 patients,199(16.2%) were complicated with anemia,who had more adverse prognostic factors compared with their counterparts without anemia.Among NKTCL patients with anemia,the proportion of patients with stage Ⅱ-ⅣV,a median age> anemia,Eastern Cooperative Oncology Group (ECOG) score of 2-4 and NK/T-cell lymphoma prognostic index (NKTCLPI) ≥ 2 was relatively high.Patients with anemia obtained worse clinical prognosis than those without anemia.The 5-year overall survival (OS) and progression-free survival (PFS) in NKTCL patients with anemia were calculated as 49.4% and 35.4%,significantly lower compared with 63.3% and 56.0% in their counterparts without anemia (both P<0.01).Single factor analysis demonstrated that anemia,age,ECOG score,group B symptom,lactate dehydrogenase,primary tumor site,primary tumor invasion and staging were the prognostic factors of OS and PFS.Multivariate analysis revealed that anemia was still the independent prognostic factor.Conclusions Anemia is not common in patients with NKTCL and these patients obtain poor clinical prognosis.Anemia is an independent prognostic factor for patients with NKTCL.
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Objective To analyze the clinical features and prognosis of extra-nodal nasal NK/T cell lymphoma originated from the larynx. Methods Clinical data of 15 cases of extra-nodal nasal NK/T-cell lymphoma originated from the larynx were retrospectively analyzed. The overall survival ( OS ) and progression-free survival ( PFS) were calculated by Kaplan-Meier survival analysis. The effect of different clinical factors on the clinical prognosis was assessed by univariate analysis. Results Among 15 patients,13 cases were male and 2 female. The median age of onset was 40 years. In 8 cases,the lesions were confined to the larynx,and only 4 cases suffered from cervical lymph node involvement. According to Ann Abor staging, 11 cases were classified as grade I,3 as gradeⅡand 1 as gradeⅢ.The median OS was 28. 0 months and the 5-year OS was 32. 0%.The median PFS was 24. 7 months and the 5-year PFS was 33. 3%.Among 14 patients with stage Ⅰ/Ⅱ,the clinical prognosis of patients receiving combined chemo-radiotherapy was significantly better than those of their counterparts undergoing radiotherapy or chemotherapy alone ( median OS:37. 2 vs. 11. 2 vs.3. 7 months,P=0. 004) . Conclusion Extra-nodal nasal NK/T cell lymphoma originated from the larynx is extremely rare, predominantly in middle-aged male patients. The general condition is relatively favorable. Patients present with multiple lesions in the early stage and relatively poor prognosis. The clinical efficacy of chemotherapy combined with radiotherapy is probably higher compared with that of radiotherapy or chemotherapy alone.
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Objective To preliminary investigate the clinical efficacy of whole brain simultaneous integrated boost intensity-modulated radiotherapy ( SIB-IMRT ) in patients diagnosed with brain metastases ( BM) . Methods Fifty-two cases of BM admitted to our hospital from January 2016 to December 2017 were equally recruited and randomly divided into the observation and control groups. Patients in the observation group were treated with SIB-IMRT, and those in the control group received conventional whole brain radiotherapy (WBRT).The clinical efficacy and prognosis were statistically compared between two groups. Results The ORR in the observation group was 77%, significantly higher than 27% in the control group (P=0. 00).The median survival in the observation group was 384 d,significantly longer compared with 211 d in the control group (P=0. 00).All patients in both groups successfully completed corresponding treatment. Acute adverse reactions were mainly 1-2 grade reactions. Conclusions SIB-IMRT is an efficacious and safe treatment of BM,which yields tolerable adverse events and deserves application in clinical practice.
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Objective To establish a radioresistant esophageal squamous cancer cell line,and to identify the radioresistant genes and mechanisms.Methods The radioresistant KYSE410-res cell line was established by repeated exposure of cell line KYSE410 to radiation.The proliferation and apoptosis of esophageal squamous cancer cells were evaluated before and after radiation.The changes in gene expression of the esophageal squamous cancer cells after radiation were determined by gene microarray and analyzed by group t test.The genes with significant difference in expression after radiation were validated.Results The KYSE410-res cells had significantly enhanced proliferation and anti-apoptosis than the KYSE410 cells (all P<0.05).The result of gene microarray showed that compared with the KYSE410 cells,the KYSE410-res cells had the expression of 463 and 251 genes upregulated and downregulated by no less than 4 folds,respectively.Those genes with different expression levels after radiation were mainly responsible for cell proliferation,adhesion,signal transduction,angiogenesis,reactive oxygen metabolism,cell damage repair,and the MAPK/ERK signaling pathway.OAS2 and UBD were key proteins in the network.In the KYSE410-res cells,the expression of HLA-DQBI,MMP1,NCAM1,ZNF521,GPC6,SELENBP1,LCN15,and TFPI-2 genes measured by real-time PCR was consistent with that measured by gene microarray.Conclusions Abnormal activation of the MAPK/ERK signaling pathway,upregulated expression of OAS2 and UBD,downregulated expression of TFPI-2,and upregulated expression of MMPs may play a role in radioresistance of esophageal cancer cells.
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As an important component of functional magnetic resonance imaging,diffusion-weighted magnetic resonance imaging (DWI) can provide qualitative and quantitative information for tumor evaluation and distinguish esophageal lesions and mediastinal lymph node metastasis.DWI-computed tomography fusion images facilitate the delineation of target volume.During radiotherapy or concurrent chemoradiotherapy for esophageal carcinoma,monitoring the changes in apparent diffusion coefficient value helps to predict the early treatment outcomes and prognosis;DWI compensates for the shortcomings of radiography alone in the evaluation of short-term treatment outcomes.This paper reviews the application of DWI in the diagnosis,delineation of target volume,assessment of treatment outcomes,and prognostic prediction in radiotherapy for esophageal carcinoma.
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A methylation is one of the important approaches for regulation of gene expression. It plays a role in tumor development and progression and is closely associated with the radiosensitivity of cancer cells. The aberrant DNA methylation in cancer cells can provide biomarkers for early diagnosis of cancer. Moreover, it can contribute to the evaluation of the efficacy of radiotherapy, radiosensitivity enhancement, prognostic assessment, and disease monitoring. In order to provide a theoretical basis for further investigation of the epigenetic mechanisms for radioresistance of cancer cells, this paper reviews the relationship between DNA methylation and radiosensitivity and the potential value of DNA methylation in radiotherapy.
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Objective To investigate the prognostic value of metabolic parameters of 18F-fluorodeoxyglucose positron emission tomography/computed tomography(FDG PET-CT)before radiotherapy in patients with esophageal cancer receiving radiotherapy. Methods We retrospectively analyzed the clinical data of 37 patients with stage Ⅱ-Ⅲ esophageal squamous cell carcinoma admitted to Anhui Provincial Hospital from 2010 to 2015,who underwent PET-CT scans within 4 weeks before radiotherapy. The following information was collected:age,sex,the location of primary lesion,clinical stage,and treatment regimen.The maximum standard uptake value(SUVmax), mean standard uptake value(SUVmean), metabolic tumor volume(MTV), PET tumor length(PTL),and total lesion glycolysis(TLG)were calculated. The optimal cut-off values of SUVmax, SUVmean,MTV,PTL,and TLG were determined by the receiver operating characteristic(ROC)curve. The Kaplan-Meier method was used to calculate survival rates,and the log-rank test was used for survival comparison and univariate prognostic analysis;the Cox model was used for multivariate prognostic analysis of significant variables. Results The area under the ROC curve suggested that MTV>TLG>PTL=0.713>0.679>0.670. The Kaplan-Meier survival analysis showed that patients had better survival time when MTV was less than 27.44 cm3,TLG was less than 166.2 g,and PTL was less than 36.74 mm(P<0.05).The Cox multivariate regression analysis showed that only MTV was an independent prognostic factor for radiotherapy in patients with esophageal cancer(P=0.000). Conclusions MTV, TLG and PTL have certain values in predicting the prognosis of patients with esophageal cancer before radiotherapy, and are helpful for selecting and adjust the clinical treatment regimen and improving the survival rate and prognosis.