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Objective To analyze the 10-year survival outcome and failure patterns for patients with nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy (IMRT),aiming to provide reference for optimized treatment for NPC.Methods Clinical data of 866 patients with NPC receiving IMRT from January 2001 to December 2008 were retrospectively analyzed.Survival analysis was performed using the Kaplan-Meier estimator.Univariate analysis was carried out by log-rank test and multivariate analysis was performed using Cox proportional hazards model.Results The median follow-up time was 132 months.The 10-year local recurrence-free survival (LRFS),distant metastasis-free survival (DMFS),progression-free survival (PFS) and disease specific survival (DSS) were 92.0％,83.4％,75.7％ and 78.6％,respectively.A total of 210 patients died including 124 patients (59.0％) from distant metastasis,which was the primary cause of death,and 47 (22.3％) from local regional recurrence.Independent negative factors of DSS included age＞50 years (P=0.00),LDH ≥ 245 IU/L (P=0.00),Hb＜ 120 g/L (P=0.01),T2-T4 staging (P=0.00),N1-N3 staging (P=0.00) and GTV-nx＞20 cm3(P=0.00).The 10-year LRFS,DMFS and DSS of stage Ⅱ NPC patients did not significantly differ after IMRT alone and chemoradiotherapy (P=0.83,0.22,0.23).For patients with stage Ⅲ NPC,the 10-year LRFS and DSS in the chemoradiotherapy arm were significantly higher than those in the IMRT alone (P=0.01,0.01),whereas no statistical significance was observed in the DMFS between two groups (P=0.14).The overall survival of stage Ⅳa+Ⅳb NPC patients is relatively poor.Conclusions IMRT can improve the long-term survival of NPC patients.Distant metastasis is the primary failure pattern.Patients with stage Ⅰ-Ⅱ NPC can obtain satisfactory survival outcomes after IMRT alone.The addition of chemotherapy can further enhance the LRFS and DSS of stage Ⅲ NPC patients.However,the optimal therapeutic strategy remains to be urgently investigated for stage a+ Ⅳb NPC patients.
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Objective To analyze the exposed dose of hippocampus(HC)of T3,T4nasopharyngeal carcinoma patients treated with intensity modulated radiotherapy(IMRT). Methods The bilateral HCs were delineated and were divided into head(HH),body(HB)and tail(HT)for 62 nasopharyngeal carcinoma patients treated with IMRT.The dose parameters of HC were then analyzed. Results The mean dose of left and right HC was(1 127±704)cGy,(1 173±762)cGy. The mean dose of left HH,HB and HT was(1 732±1029)cGy,(820±632)cGy,(423±366)cGy(P=0.000);while the mean dose of right HH, HB and HT was(1 985±1101)cGy,(837±531)cGy,(432±343)cGy(P=0.000).The exposed dose and the volume exposed in different dose of HH were obviously higher than those of HB and HT.The dose parameters of HH,HB and HT decreased in turn. The involvement of sphenoid sinus,ethmoid sinus and cavernous sinus correlated with high exposed dose of HC. Conclusions The exposed dose of HH,HB and HT was different in nasopharyngeal carcinoma patients treated with IMRT.The exposed dose of HH was the highest,which should be emphasized especially. The involvement of sphenoid sinus,ethmoid sinus and cavernous sinus suggest high exposed dose of HC.
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Objective To evaluate the relationship between the volume of parotid glands and radiation-induced xerostomia in patients with nasopharyngeal carcinoma(NPC). Methods A total of 199 patients with NPC who were admitted to our hospital from 2015 to 2016 were enrolled as subjects. According to the initial volume of parotid glands, all patients were divided into large parotid group and small parotid group. The incidence of xerostomia after radiotherapy and dosimetric parameters were compared between the two groups. Comparison of categorical data was made by x2 test. Comparison of continuous data was made by t-test or nonparametric test. Comparison of dose-volume histogram index was made by nonparametric test. Results There was no difference in the severity of xerostomia between the two groups at 3 and 6 months after radiotherapy. At one year after radiotherapy,the large parotid group had significantly milder xerostomia than the small parotid group(P=0.035).The small parotid group had a higher dose delivered to both parotid glands than the large parotid group. There was no difference in the mean dose to the submandibular gland between the two groups. Conclusions The initial volume of parotid glands is one of the influencing factors for the grade of xerostomia after radiotherapy. Patients with large parotid glands have better recovery from xerostomia after radiotherapy than those with small parotid glands. For patients with small parotid glands, more attention should be paid to reducing the dose to protect parotid glands.
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Objective@#To investigate the change trend of late complications of patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) after 5-year follow up according to the clinician-and patient-reported outcomes.@*Methods@#From 2014 to 2015, NPC patients surviving> 5 years after radical IMRT at our outpatients department and were followed up 3 years later. The late complications were evaluated by the clinician based upon the CTCAE 4.0 rating criteria and assessed by patients themselves into 5 grades including very good, good, fair, poor and very poor.@*Results@#A total of 116 NPC patients were included in the first survey with a median follow-up time of 6.5 years (range, 5.0-11.3 years). During the second survey, 21 patients were lost to follow-up, 7 patients developed nasopharyngeal recurrence or metastases, 7 patients had second primary tumors and 81 patients were eligible for final analysis. In the first survey, the most common clinician-reported ≥grade 2 late complications were subcutaneous fibrosis (n=17, 21.0%) and hearing impairment (n=13, 16.0%). The most frequent patient-reported "poor" and "very poor" late complications included dental caries (n=27, 33.3%), subcutaneous fibrosis (n=17, 21.0%) and hearing impairment (n=12, 14.8%). During the second survey, the most common complications were aggravated or new late complications occurred including hearing impairment (n=16, 20.0%), dental caries (n=16, 20.0%) and posterior cranial neuropathy (n=9, 11.0%).@*Conclusions@#The incidence of late complications is high after radical IMRT for NPC. During the long-term survival, subcutaneous fibrosis and hearing impairment are the main late complications. The incidence of hearing impairment, dental caries and posterior cranial neuropathy is increased over time. The symptoms of hearing impairment and dental caries are aggravated in partial patients.
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Objective To investigate the mobidity and risk factors for primary hypothyroidism (HT) in nasopharyngeal cancer (NPC) patients treated with intensity-modulated radiotherapy (IMRT). Methods 113 NPC patients with complete clinical information who received IMRT from 2008-2010 were retrospectively analyzed. Thyroid function assessments before and after IMRT were periodically monitored. Various clinical and dosimetric parameters were obtained including Dmin ,Dmax ,Dmean ,V30 ,V35 ,V40 ,V45 ,V50 , V55 ,V60 , V65 , V70 ( thyroid gland ) , PDmin , PDmax , PDmean ( pituitary gland ) . Univariate and multivariate logistic regression analyses were performed to identify predictors of HT. Results After a median follow-up period of 62 months,41 patients ( 363%) had clinical HT,and 28 patients ( 248%) developed subclinical HT. Univariate analysis revealed that younger age, mean dose to the thyroid gland, V40 , V45 , V50 , V55 , V60 were correlated with developing HT ( all P<005 ) . On multivariate analysis including patient, tumor, and treatment variables,younger age ( P=0002) and V50 ( P=0002) remained statistically significant. We found that the cutoff value of V50(50%) may be an valuable evaluation marker of HT.Combined with age to predict the HT,the area under ROC curve is 0728.The endpoint event rate of the patients whose level of V50 is above 50% and age level below 45 years were 793%,whlie the date in patients whose level of V50 is below 50% and age level above 45 years was 318%. Conclusions Thyroid V50 above 50% is predictive of primary HT after IMRT for NPC patient, Our results suggested that restricting V50<50% during IMRT planning may facilitate the reduction in incidence of HT for the younger patients.
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Objective To investigate the impact of actual gantry angle on the accuracy of intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). Methods A total of 27 patients with NPC were enrolled in this study. IMRT plans were designed with Pinnacle treatment planning system (TPS),and 8 beams with an interval of 30°(within 0°-360°) were selected for each plan. These plans were divided into plan A and plan B according to the beam parameters. In plan A,the minimum sub-field area was 5 cm2 ,the minimum number of sub-field monitor unit ( MU) was 5,and the maximum sub-field number was 80;in plan B,the minimum sub-field area was 8 cm2 ,the minimum number of sub-field MUs was 8,and the maximum sub-field number was 60.The gamma passing rate using the criteria of 3%/3 mm and 2%/2 mm at actual and zero degree gantry angles were calculated using Mapcheck 2 device for dose verification,and were compared with the paired t-test. The relationship between the above differences (Δ value) and the beam angle or the beam parameters was also analyzed. Results In plan A with the criteria of 3%/3 mm, the beams were significantly different (P=0000-0007) except for at angles of 270°,300°,and 300°,and the mean Δ value was 090%;under the criteria of 2%/2 mm,all beams were significantly different ( P=0000-0019) except for at an angle of 300°,and the meanΔvalue was 272%.In plan B with the criteria of 3%/3 mm,the beams showed no significant difference ( P=0052-0639) except for at an angle of 300 ° ,and the mean Δ value was 040%;under the criteria of 2%/2 mm,all beams showed no significant difference ( P>005) except for at angles of 210°,240°,270°,and 300°,and the meanΔvalue was 152%.When the plan B parameters were used, the Δ value was reduced;the results of two verification methods were more consistent,so the accuracy was also improved. Conclusions Compared with the validation method at zero degree gantry angle,the validation method at an actual gantry angle is associated with reduced gamma passing rate because of some factors such as gravity,which is not significantly related to the beam angle,but the beam parameters. In the design of IMRT plans for NPC,the total number of sub-fields should be decreased as far as possible,and the minimum sub-field area and the minimum number of MU should be increased, so as to improve the accuracy of treatment plans.
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The application of precision medicine in cancer treatment is becoming increasingly common as a result of the continuous advancement in basic research and physical techniques.The revolution of radiotherapy techniques, development of multimodal imaging technology, application of biological target dose carving and adaptive radiotherapy, availability of big data-based radiotherapy planning systems, and selection of chemotherapy regimen have all made the treatment of nasopharyngeal carcinoma increasingly precise.The growing interaction between laboratory research and clinical practice not only underscores the importance of translational medicine, but also prompts the development of biological immunotherapy and screening of prognostic factors.As a result, these changes mark the beginning of a new era for the diagnosis and treatment of nasopharyngeal carcinoma.This review provides a summary from 61 articles on the current progress in translational study and clinical application of precision medicine in nasopharyngeal carcinoma.
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Objective To propose a new suggestion for the clinical downstaging of nasopharyngeal carcinoma (NPC) in the era of intensity-modulated radiotherapy (IMRT) without changing the current T,N,and M staging system.Methods We reviewed the records of 536 NPC patients treated in Sun Yat-Sen University Cancer Center from January 2002 to December 2006.The Kaplan-Meier method was used to calculate the disease-specific survival (DSS) rate,and the log-rank test was used for survival difference analysis.The Cox regression model was used to calculate the hazard ratio (HR) of each subset.ResultsAccording to the 7th edition of UICC/AJCC staging system,the 5-year DSS rates of stage Ⅰ-Ⅲ patients (except T3N2M0) were all more than 85%(P>0.05),those of stage ⅣA and ⅣB patients were 71.8% and 46.2%,respectively (P=0.171),and that of stage ⅠVC patients was only 24.0%.In stage Ⅲ,the 5-year DSS rate of non-T3N2M0 patients (91.5%) was significantly higher than that of T3N2M0 patients (78.6%)(P=0.042),but there was no significant difference in DSS between T3N2M0 patients and stage ⅣA and ⅣB patients.Based on the above results,new stage Ⅰ included T1-3N0-1M0 and T1-2N2M0,new stage Ⅱ included T3N2M0,T4N0-2M0,and TxN3M0,and new stage Ⅲ included TxNxM1.The 5-year DSS rates of new stage Ⅰ,Ⅱ,and Ⅲ patients were 93.3%,72.7%,and 24.0%,respectively (P=0.000).Compared with new stage Ⅰ patients,new stage Ⅱ and Ⅲ patients had HRs of 4.01 and 16.76,respectively,for 5-year DSS.Conclusions In the era of IMRT,the new clinical staging system (stages Ⅰ,Ⅱ,and Ⅲ) helps with prognostic evaluation and clinical treatment.
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Objective To investigate the tolerated dose of the optic nerves and chiasm in patients with locally advanced nasopharyngeal carcinoma(NPC)treated with intensity-modulated radiotherapy (IMRT). Methods A retrospective analysis was performed on dose characteristics and the incidence of radiation optic neuropathy in 108 patients with locally advanced NPC treated with IMRT at D 2>55 Gy in the optic nerves and chiasm in our hospital between May 2009 and December 2013. The Common Terminology Criteria for Adverse Events(CTCAE)Version 3.0 grading criteria were used for evaluating adverse reactions of the optic nerves and optic chiasm.A logistic regression analysis was performed to assess the risk factors for the development of radiation-induced optic neuropathy(RION). Results No patient had severe RION (grade 3-5),although 7 of the 108 patients had mild optic nerve disorder(grade 1-2). No patient-or treatment-related factors were found to be associated with the development of RION(P>0.05). With a median follow-up of 46 months(range,13-91 months),the 3-year estimated overall survival,local recurrence-free survival,and distant metastasis-free survival rates were 90.0%,94.5%,and 86.4%, respectively. Conclusions The dose constraint of<55 Gy derived for optic nerves and chiasm from conventional radiotherapy does not seem to apply to IMRT. For advanced NPC patients treated with IMRT, the dose constraints of optic nerves and chiasm might be relaxed in order to improve target coverage.
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Objective To analyze the radiation doses to the head, body, and tail of the hippocampus in intensity-modulated radiotherapy(IMRT)for nasopharyngeal carcinoma(NPC). Methods Ten NPC patients treated with IMRT were selected,and the head, body, and tail of both hippocampi were delineated on T1-weighted images. The doses to the hippocampus were then analyzed. WAIS-CR speech test results were tested by paired sample t-test. Results The mean doses to left and right hippocampi were 1 147±976 cGy and 1 011±602 cGy, respectively. The mean doses to the head, body, and tail of the left hippocampus were 1 739± 1 317 cGy, 890± 982 cGy, and 547± 688 cGy, respectively(P=0.042);the mean doses to the head,body,and tail of the right hippocampus were 1 691±942 cGy,744±483 cGy,and 531±603 cGy,respectively(P=0.002).The dose to the hippocampus decreased from the head to the tail, and the irradiated volume also decreased as the dose varied. Conclusions The dose to hippocampus decreases from the head to the tail in NPC patients treated with IMRT,which is worthy of attention.
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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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Objective To explore the relationship between positive cervical lymph nodes and distant metastasis after intensity-modulated radiotherapy(IMRT)in patients with nasopharyngeal carcinoma(NPC). Methods A retrospective analysis was performed on the clinical data of 474 patients who were newly diagnosed with NPC but no distant metastasis and received IMRT from 2010 to 2012. The survival rates were calculated by the Kaplan-Meier method. The log-rank test was used for comparison of survival rates and univariate prognostic analysis. The multivariate analysis was made by the Cox regression model. Results In the 474 patients, 400 had positive cervical lymph nodes and 122 had residual masses in the neck after IMRT. The four-year distant metastasis, overall survival, disease-free survival, local relapse-free survival, and distant metastasis-free survival(DMFS)rates were 13.71%(65/474), 82.9%, 81.4%, 93.5%, and 86.3%, respectively. The univariate and multivariate analyses showed that treatment approach, lymph node metastases in lower neck Ⅳ/Ⅴb/Ⅴcregions, the greatest diameter of the positive cervical lymph nodes, the diameter of residual lymph nodes, and time to lymph node recession were independent prognostic factors for DMFS(all P<0.05). Conclusions Chemoradiotherapy can reduce the distant metastasis rate after IMRT for NPC. The larger the cervical lymph nodes are,the more likely there are residual masses;the larger the residual cervical lymph nodes are, the higher risk of distant metastasis there is. Large cervical lymph nodes(≥6 cm),residual masses larger than 1 cm,and residual masses at 3 months after IMRT are negative prognostic factors for DMFS after IMRT for NPC. Better intervention treatment approaches need to be explored.
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Objective To investigate the mobidity and risk factors for primary hypothyroidism (HT) in nasopharyngeal cancer (NPC) patients treated with intensity-modulated radiotherapy (IMRT). Methods 113 NPC patients with complete clinical information who received IMRT from 2008-2010 were retrospectively analyzed. Thyroid function assessments before and after IMRT were periodically monitored. Various clinical and dosimetric parameters were obtained including Dmin ,Dmax ,Dmean ,V30 ,V35 ,V40 ,V45 ,V50 , V55 ,V60 , V65 , V70 ( thyroid gland ) , PDmin , PDmax , PDmean ( pituitary gland ) . Univariate and multivariate logistic regression analyses were performed to identify predictors of HT. Results After a median follow-up period of 62 months,41 patients ( 363%) had clinical HT,and 28 patients ( 248%) developed subclinical HT. Univariate analysis revealed that younger age, mean dose to the thyroid gland, V40 , V45 , V50 , V55 , V60 were correlated with developing HT ( all P<005 ) . On multivariate analysis including patient, tumor, and treatment variables,younger age ( P=0002) and V50 ( P=0002) remained statistically significant. We found that the cutoff value of V50(50%) may be an valuable evaluation marker of HT.Combined with age to predict the HT,the area under ROC curve is 0728.The endpoint event rate of the patients whose level of V50 is above 50% and age level below 45 years were 793%,whlie the date in patients whose level of V50 is below 50% and age level above 45 years was 318%. Conclusions Thyroid V50 above 50% is predictive of primary HT after IMRT for NPC patient, Our results suggested that restricting V50<50% during IMRT planning may facilitate the reduction in incidence of HT for the younger patients.
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Objective To investigate the impact of actual gantry angle on the accuracy of intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). Methods A total of 27 patients with NPC were enrolled in this study. IMRT plans were designed with Pinnacle treatment planning system (TPS),and 8 beams with an interval of 30°(within 0°-360°) were selected for each plan. These plans were divided into plan A and plan B according to the beam parameters. In plan A,the minimum sub-field area was 5 cm2 ,the minimum number of sub-field monitor unit ( MU) was 5,and the maximum sub-field number was 80;in plan B,the minimum sub-field area was 8 cm2 ,the minimum number of sub-field MUs was 8,and the maximum sub-field number was 60.The gamma passing rate using the criteria of 3%/3 mm and 2%/2 mm at actual and zero degree gantry angles were calculated using Mapcheck 2 device for dose verification,and were compared with the paired t-test. The relationship between the above differences (Δ value) and the beam angle or the beam parameters was also analyzed. Results In plan A with the criteria of 3%/3 mm, the beams were significantly different (P=0000-0007) except for at angles of 270°,300°,and 300°,and the mean Δ value was 090%;under the criteria of 2%/2 mm,all beams were significantly different ( P=0000-0019) except for at an angle of 300°,and the meanΔvalue was 272%.In plan B with the criteria of 3%/3 mm,the beams showed no significant difference ( P=0052-0639) except for at an angle of 300 ° ,and the mean Δ value was 040%;under the criteria of 2%/2 mm,all beams showed no significant difference ( P>005) except for at angles of 210°,240°,270°,and 300°,and the meanΔvalue was 152%.When the plan B parameters were used, the Δ value was reduced;the results of two verification methods were more consistent,so the accuracy was also improved. Conclusions Compared with the validation method at zero degree gantry angle,the validation method at an actual gantry angle is associated with reduced gamma passing rate because of some factors such as gravity,which is not significantly related to the beam angle,but the beam parameters. In the design of IMRT plans for NPC,the total number of sub-fields should be decreased as far as possible,and the minimum sub-field area and the minimum number of MU should be increased, so as to improve the accuracy of treatment plans.
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Objective To evaluate the dosimetric effects of air cavity on primary tumor and organs at risk (OARs) during intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma patients.Methods Nine patients with nasopharyngeal carcinoma had CT simulation before treatment and on the 25 fraction of radiotherapy.Radiotherapy plan1 was first created by delineating the target volumes and OARs on the first CT image, which was then copied and merged with the second CT image.Air cavity that was formed following tumor volume regression was delineated on the first CT image, and the density of air cavity was set to zero.A new gross target volume (GTV) was formed by subtracting the air cavity from the original GTV, and the new CT image was named CTAir.Plan2 was then created by calculating the dose distribution on CTAir using the same portals and parameters as Plan1.Assuming that Plan1 and Plan2 were both used throughout the course of radiotherapy, the dosimetric parameters of nasopharyngeal tumor and OARs in the absence and presence of air cavity were then compared using the paired t-test.Results Dmean, D95, D90, D10, and D5 of tumor were significantly higher in plan2 than in plan1(P=0.000, 0.001, 0.001, 0.001, and 0.005, respectively), with a<0.5 Gy increase in dose.A dose build-up effect was observed within the tumor region posterior to the air cavity, where the highest dose was 1.4 cm posterior to the air cavity, resulting in a dose difference of 0.36 Gy.In addition, D2cc and D1cc of the brain stem were significantly higher in plan2 than in plan1(P=0.036 and 0.044, respectively).Dmax of the optical chiasm, left optical nerve, and right optical nerve were also increased in the presence of air cavity (P=0.438, 0.434, and 0.477, respectively), but the change in dose was<0.12 Gy.Conclusions Air cavity induces a small but negligible increase in the tumor and OARs dose in patients with nasopharyngeal carcinoma during IMRT.However, closer monitoring should be conducted for patients with OARs that is close to or has surpassed tolerance prior to radiotherapy.
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Objective To examine the application of On-Board Imaging (OBI) system-based image-guided radiotherapy (IGRT) in the improvement of the precision of intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma.Methods Ten patients with nasopharyngeal carcinoma were treated with IMRT using the OBI system. The IGRT images after positioning, position adjustment, and treatment were observed and recorded to investigate the image difference between CT simulation and IGRT. Results The deviations in the x (lateral), y (cranial-caudal), and z (ventral-dorsal) directions between CT simulation and IGRT images were 0.22±1.00 mm,-0.37±1.28 mm, and 0.04±1.36 mm, respectively, after positioning, 0.29±0.76 mm,-0.04±0.78 mm, and -0.01±0.92 mm, respectively, after position adjustment, and 0.20±0.78 mm, 0.16±0.80 mm, and 0.05±0.92 mm, respectively, after treatment. The probabilities of a ≤1 mm deviation in the x, y, and z directions were 81.0%, 77.6%, and 88.2%, respectively, after positioning, 92.5%, 96.4%, and 96.4%, respectively, after position adjustment, and 91.7%, 94.9%, and 96.8%, respectively, after treatment. Conclusions The application of OBI system-based IGRT is very important in the improvement of the precision of fractionated IMRT for patients with nasopharyngeal carcinoma. The position of the patient should be adjusted based on the IGRT image after positioning in order to correct set-up error and effectively increase the precision of fractionated IMRT.
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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 establish a new T staging system for nasopharyngeal carcinoma ( NPC) based on magnetic resonances imaging ( MRI) and intensity?modulated radiotherapy ( IMRT) . Methods A retrospective analysis was performed on the clinical data of 608 patients who were newly diagnosed with non?metastatic NPC by MRI and treated with IMRT in our hospital from 2008 to 2010. All patients were staged according to the 7th edition of the UICC/AJCC staging system for NPC. The survival rates were calculated using the Kaplan?Meier method and analyzed using the log?rank test. The Cox regression model was used for multivariate analyses. To deal with the deficiency in the current UICC/AJCC staging system, a new T staging system for NPC was established and systematically evaluated. Results The 5?year follow?up rate was 94?5%. The 5?year overall survival (OS), disease?free survival, local relapse?free survival (LRFS), and distant metastasis?free survival rates were 81?5%, 80?1%, 86?0%, and 81?1%, respectively. The univariate and multivariate analyses showed that the anatomic structures of nasopharynx, parapharyngeal space, and skull base were influencing factors for the OS rate (P=0?000?0?045). New T staging criteria were proposed based on the risk differences and survival curves:stage T1:invasion of the nasopharynx, parapharyngeal space, oropharynx, nasal cavity, skull base, and internal pterygoid muscle;stage T2:invasion of the external pterygoid muscle, paranasal sinus, intracalvarium, infratemporal fossa, and cranial nerves. The proposed T staging system achieved a good separation in both OS and LRFS curves. Conclusions The proposed new T staging system gives an objective prognostic prediction in patients with NPC, which provides an exploratory attempt toward a new clinical staging system for NPC.
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Objective To retrospectively compare the efficacy and toxicity between intensity?modulated radiotherapy ( IMRT ) combined with chemotherapy plus targeted therapy and IMRT combined with chemotherapy in the treatment of patients with locally advanced nasopharyngeal carcinoma ( NPC) , and to preliminarily evaluate the necessity of adding targeted drugs to standard chemoradiotherapy . Methods Forty?two patients with stage Ⅲ?Ⅳb NPC who received IMRT combined with concurrent ± adjuvant chemotherapy plus targeted molecular therapy from January 2007 to December 2012 were assigned to experiment group,while 168 patients who received IMRT combined with concurrent ±adjuvant chemotherapy within the same period were assigned to control group. The experiment group was paired with the control group at a ratio of 1vs.4.The survival rates were caculated using Kaplan?Meier method and analyzed using log?rank method,other comparison was perfomed by χ2?test. Results The follow?up rate was 100%.The sample size of experiment group and control group were 42 patients and 168 patients. There were no significant differences in the 3?year OS, LRFS, or DMFS rates between the experiment group and the control group (94?3% vs. 87?3%, P=0?647;100?0% vs. 94?6%,P=0?193;92?2% vs. 89?1%, P=0?744).There were also no significant differences in the incidence rates of grade Ⅲ?Ⅳ gastrointestinal reaction or marrow suppression between the two groups ( 7?1%( 3/42 ) vs. 3?6%( 6/168 ) , P=0?388;26?2%( 11/42 ) vs. 17?3%(29/168),P=0?272).However,the experiment group had significantly higher incidence of grade Ⅲ?Ⅳoral mucositis than the control group ( 40?5%( 17/42 ) vs . 14?9%( 25/168 ) , P=0?000 ) . Conclusions The preliminary results indicate that IMRT combined with chemotherapy plus targeted molecular therapy is not able to substantially improve the OS, LRFS, or DMFS rates in patients with locally advanced NPC. Moreover, it may aggravate radiochemotherapy?induced oral mucositis.
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Objective To explore the upper bound of Ⅱb region in the clinical target volume ( CTV ) for intensity?modulated radiotherapy ( IMRT ) for nasopharyngeal carcinoma ( NPC ) , and to establish a standard for personalized reduction in the range ofⅡb region. Methods A retrospective analysis was performed on the IMRT results of 142 patients newly diagnosed with NPC who were admitted to our hospital from 2012 to 2014. According to the American Joint Committee on Cancer 2010 staging system, there were 8 patients with stageⅠ disease, 37 stage Ⅱ, 41 stage Ⅲ, and 56 stage Ⅳ. The distribution pattern of cervical lymph nodes in NPC was studied based on the imaging results. Comparison of the dose to parotid glands between patients with and without reduction in the range ofⅡb region was made by t test and t'test. Results The metastasis rates of the most common diseased lymph nodes, lateral retropharyngeal lymph node and Ⅱb lymph node, were 75?4% and 67?6%, respectively. In the patients with metastases inⅡb region, 51?0% had high?risk positive lymph nodes and 6?3% had positive lymph nodes beyond the upper bound of Ⅱb region defined by the Radiation Therapy Oncology Group system. It was safe to narrow down Ⅱb region in patients who met the formulated standard. The D50 and V26 values for parotid glands were significantly reduced after optimization of CTV ( P=0?000) . Conclusions The upper bound ofⅡb region, in principle, should reach the lateral skull base during the delineation of the cervical CTV for NPC. In order to protect the parotid glands, however, personalized reduction in the upper bound of Ⅱb region is recommended for patients who meet the formulated standard.