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Intensity-modulated radiotherapy(IMRT)is the first-line treatment for nasopharyngeal carcinoma currently. Previous studies have shown that regression of primary tumor and metastatic lymph nodes or a decrease in body weight causes the contour of normal organs and head-and-neck to shrink during the course of radiotherapy, which may lead to underdose in primary tumor and overdose in organs at risk (OARs)and then adversely affect treatment outcomes. Replanning during the course of radiotherapy can maintain the dose to target volume and reduce the exposure of OARs, which improves outcomes in some patients. For replanning during the course of IMRT, however, the advantages have not been widely recognized and there is still a long way to go before widely accepted timing and frequency of replanning are set up. Further studies are needed to figure out how to identify patients appropriate for plan modification.
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Objective To investigate the value of FDG PET-CT in the outcome assessment and prognostic evaluation for recurrent nasopharyngeal carcinoma (rNPC).Methods From January 2008 to December 2013,92 rNPC patients were treated in our center,who were histologically or radiologically diagnosed and re-staged according to the 2008 clinical staging system for nasopharyngeal carcinoma in China.The numbers of patients in stage Ⅰ,stage Ⅱ,stage Ⅲ,and stage Ⅳ were 8,11,39,and 34,respectively.According to the recurrent T stage (rT),the numbers of patients in rT1,rT2,rT3,and rT4 were 10,11,38,and 33,respectively.Twenty-eight patients had recurrence in the neck lymph nodes.All patients underwent pretreatment FDG PET-CT for the whole body or head/neck,and treated by radiotherapy with or without chemotherapy.The relationship of maximum standard uptake value (SUVmax) and clinical factors with clinical outcomes was analyzed.The Kaplan-Meier method was used to calculate overall survival (OS),disease-free survival (DFS),local recurrence-free survival (LRFS),regional recurrence-free survival (RRFS),and distant metastasis-free survival (DMFS).The log-rank test was used for survival difference analysis and univariate prognostic analysis.The Cox model was used for multivariate prognostic analysis.Results The 3-year OS,DFS,LRFS,RRFS,and DMFS were 33.6％,32.1％,32.8％,31.8％,and 33.7％,respectively.The median SUVmax was 8.35 (2.7-21.5).The SUVmax of 7.0 was taken as the optimal cut-off value for all patients.Patients with SUVmax ≤7.0 had a significantly higher 3-year OS rate than those with SUVm ax ＞7.0 (42.0％ vs.28.3％,P=0.019).The univariate analysis revealed that patient age,SUV and rN were significantly associated with OS (P=0.023,0.019,and 0.002).The multivariate analysis showed that SUVmax and rN were significant influencing factors for OS,DFS,and DMFS (HR=1.68,P=0.045 and HR=2.23,P=0.003;HR=1.67,P=0.042 and HR=2.39,P=0.001;HR=1.77,P=0.025 and HR=2.40,P=0.001).Conclusions SUVmax may be one of the useful prognostic factors for OS,DFS,and DMFS in rNPC patients.
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Objective To investigate the benefits of replanning after induction chemotherapy(IC) by analyzing the dosimetric impact of IC on intensity-modulated radiotherapy(IMRT)for locally advanced nasopharyngeal carcinoma(NPC)and the dosimetric characteristics of replanning after IC, and to provide data for the rational design of clinical radiotherapy plans. Methods 16 NPC patients underwent contrast-enhanced CT scan once before and after IC.Target volumes were delineated and the chemotherapy plans were created,defined as Plan-1 and Plan-2,respectively. Then the target structure after IC was copied to Plan-1, generating the third plan, defined as Plan-1-2. The paired t-test was used to compare the dosimetric parameters between Plan-1 and Plan-1-2 and between Plan-2 and Plan-1-2. Results Plan-1 vs. Plan-1-2:Plan-1-2 showed significantly reduced D meanof target volume compared with Plan-1(P<0.05). Plan-1-2 significantly increased D meanand D maxof the spinal cord(P<0.05),although significantly reduced D mean of the brain stem and D maxof the temporal lobes compared with Plan-1. Plan-1-2 also had significantly reduced conformity index(CI)and significantly increased homogeneity index(HI)for the target volume compared with Plan-1(P<0.05). Plan-2 vs. Plan-1-2:Compared with Plan-1-2, Plan-2 significantly increased D meanand D minof gross tumor volume(GTV)and primary GTV(P<0.05)and significantly reduced D meanof the temporal lobes and D maxand D meanof the spinal cord(P<0.05), with D max decreased to 430.48 cGy;Plan-2 had significantly increased CI and significantly reduced HI for the target volume compared with Plan-1-2(all P<0.05). Conclusions IMRT plan-1 after IC has worse dosimetric distribution,while replanning after IC has more dosimetric benefits.
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18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) is the integration of functional imaging and anatomic information,which is found to be particularly valuable in TNM staging,tumor volume delineating,post-treatment assessment,identification of recurrent and residual nasopharyngeal carcinoma (NPC).The combination of 18F-FDG PET-CT with other image technologies,different tracer agents,and specific molecular biomarkers can improve the application value of 18F-FDG PET-CT in NPC.
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As induction chemotherapy goes on,target volume,dose distribution in the surrounding organs at risk (OARs),and target dose conformity all change.Therefore,the question is how to develop reasonable radiotherapy plans in clinical practice.Induction chemotherapy followed by radiotherapy is commonly used around the world,but it is recommended to delineate the target volume based on the gross tumor volume before induction chemotherapy and not to reduce the dose.This point of view lacks the basis of evidence-based medicine.The experts and scholars in China clarify the advantages of radiotherapy plans after induction chemotherapy from the aspects of reducing the target volume,reducing the volume of high-dose region in the target volume,increasing the uniform dose coverage in target volume,reducing dose to OARs,and increasing dose conformity.However,at present,there are no objective data on its long-term efficacy and benefit.Besides,no consensus has been reached on how to delineate the target volume and determine the dose distribution after induction chemotherapy,and further studies are needed.
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Objective To investigate the influence of intensity-modulated radiation pattern on ra-diobiological effects of nasopharyngeal carcinoma cell line CNE2.Methods Colony formation assay was used to calculate cell surviving fraction, and compare the cell survival curves and the surviving fraction with single-hit multi-target model fitting survival curves to different delivery time and dose rates.Results ⑴Nasopharyngeal carcinoma cell line CNE2 was irradiated on two models:conventional radiation ( CR) mod-el;intensity modulated radiation model ( IMRT model, which was divided into 10 min IMRT irradiated group, 15 min irradiated group, and 20 min irradiated group) .Except that the parameters of radiation biol-ogy did no significantly differ between CR model and 10 min IMRT irradiated group ( P >0.05) , the other groups among radiobiology parameters surviving fraction (SF2), quasi-threshold dose(Dq) and extrapolation number(N) were all significant differences ( P SF2 600 Mu/min ( P <0.05) when the CNE2 cells were treated with dose rates of 300 Mu /min and 600 Mu/min.Conclusions ⑴There were not significant changes in the biological effects until the delivery time prolonged to more than 10 minutes.When the delivery time extended to more than 15 minutes, the survival fraction was increasing with the radiation time risen.⑵The dose rates used in the experiment did not show any effect on the radiobiology parameters without SF2 .
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Objective To investigate the principle and method of breast-concerving therapy of early-stage breast cancer.Methods The clinical data of 31 cases of early-stage breast cancer who were conserved breast were analysed retrospectively from January 1992 to April 2002. 14 cases performed wide lumpectomy plus axillary nodes dissection,5 cases performed wide lumpectomy, 11 cases performed lumpectomy and 1 case did not perform operation. After operation 17 cases received radiotherapy and chemotherapy,8 cases received only radiotherapy,3 cases received only chemotherapy and 3 cases did not receive radio-chemotherapy.Results Surviving time of all patients was 6 to 122 months.Mean surviving time was 32?5 months.Median of survival time was 22 months.Among 31 patients 1 case died of metastasis due to refusing chemotherapy,the other were alive now and 10 cases of all patients have survival over 3 years. Local recurrence was found in 1 case after 5 years,but he did not take chemotherapy and radiotherapy. Fairly good cosmetic outcome was obtained in 29 patients(93 5%).Conclusions It probably is ideal method that the wide lumpectomy plus axillary nodes dissection combines rationally with radiotherapy and chemotherapy in breast-conserving treatment of early- stage breast cancer.
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Objective To study the therapeutic effect and complication of external beam radiotherapy (EBR) plus intracavitary brachytherapy (IB) on nasopharyngeal carcinoma(NPC). Methods 52 patients with stage T 1,T 2 NPC were divided into two groups, 26 patients treated by EBR and the other 26 patients treated by EBR plus IB (combined radiotherapy group). IB was given to the patients of combined radiotherapy group when the external radiotherapy dose amounted to 40Gy,50Gy and 60Gy, respectively. Results The 3-year local control rates of combined radiotherapy group and EBR group were 100% and 73.08%, respectively (P0.05). Conclusions External beam radiotherapy combined with intacavitary brachytherapy for stage T 1, T 2 NPC may rise the local control rates, and reduce the exteral beam radiation dose and the complication.
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Objective To examine the variation of protein expression in nasopharyngeal carcinoma cell lines with different biological characteristics and to identify the radiobiological associated proteins. Methods Biological characteristics of 5-8F and 6-10B were compared by flow cytometry assay after irradia- tion. The total proteins of 5-8F and 6-10B were separated by immobilized pH gradient(IPG) IEF-SDS two- dimensional gel electrophoresis technique. The differentially expressed proteins were cut from the gel and di- gested into peptides for MALDI-TOF MS and the Q-TOF mass spectrometric analysis. Identification of pro- tein was made through searching in protein sequence database. Protein expressions were examined by western blot and immunohistochemistry method. Results Nine most differentially expressed proteins between 5-8F cell and 6-10B cell were identified, p73 and CK19 expression examined by western blot were conformal with that by proteomic method, p73 expression in 5-8F cell was higher than in 6-10B cell. CK19 expression in 6- 10B cell was higher than in 5-8F cell. Conclusion Differentially expression of proteins exist in nasopha- ryngeal carcinoma cell lines with different biological characteristics. These proteins may be associated with cell radiobiological characteristic with the p73 as a potential biomarker.