| Objectives:1.The prognosis and late adverse reaction of patients with nasopharyngeal c arcinoma treated with intensity-modulated radiation therapy(Intensity-modulated ra diation therapy,IMRT)were retrospectively analyzed.The results will provide fa vorable clinical basis for the treatment deprogramming to nasopharyngeal carcino ma.2.The relationship between the dose-volume characteristics of pharyngeal co nstrictor muscles and swallowing dysfunction induced by radiation in patients wit h nasopharyngeal carcinoma(NPC)was investigated.Methods:1.47 patients with nasopharyngeal carcinoma underwent radical IMRT fromJanuary 2014 to December 2015 in the Second Affiliated Hospital of Dalian M edical University were followed up.Evaluate their survival period and late adver se reactions.Late adverse reactions were referenced to the RTOG/EORTC Radiat ion Morbidity Scoring Criteria.2.The patients were divided into two groups according to the follow-up res ults of patients with adverse reactions.Dysphagia group was set as DY group,d ysphagia free group was set as DF group.Compare the clinical characteristics ofthe two groups.3.Images of all patients in the two groups were acquired at a 0.3cm slice intervals with the use of Siemens multi-slice spiral CT,extending the scan from the head to 3 cm below the clavicle.The datas and images scanned were transm itted to the Varian work center Eclipse 11.0 planning system.The target volume,organs at risk and pharyngeal constrictor muscle was delineated on CT images in radiation treatment planning system using a Cancer Hospital of Chinese Acade my of Medical Sciences(CAMS)endorsed atlas for nasopharyngeal carcinoma an d the Ying et al protocols.Pharyngeal constrictor muscle is divided into three pa rts: the superior constrictor muscle(SCM),the middle constrictor muscle(MCM)and the inferior constrictor muscle(ICM).Calculate and compare the dose-volu me histogram(DVH)parameters of pharyngeal constrictor muscle(PCM)as a w hole and be divided into three parts(SCM,MCM and ICM)of patients in two groups.Result:1.Prognosis and adverse reaction1.1 Prognosis47 patients with a median follow-up time of 12 months(6 ~ 24 months).1,2 year overall survival rates were 99.38% and 96.20%;no local recurrence survi val rates were 97.16% and 93.26%;no regional progress survival rates were 97.35% and 94.36%;no distant metastasis survival rates were 92.44% and 90.27%.1.2 Late adverse reactionsThe follow-up results showed that the incidence of xerostomia were 57.45%and 36.17%,respectively for 1,2 levels late adverse reaction;the incidence of mucositis were 23.40% and 19.15%,respectively for 1,2 levels late adverse re action;the incidence of radioactive dermatitis were 12.76% and 23.40%,respecti vely for 1,2 levels late adverse reaction.The incidence of dysphagia were 19.15%and 8.51%,respectively for 1,2 levels late adverse reaction.2.Comparison of clinical characteristics between the two groupsThe difference between the two groups of patients with N stage was statist ically significant.The result of the comparison showed that incidence of RISD w as associated with N stage.3.DVH parameters in two groupsThe DVH parameters in the group of DY: The mean values of Dmean,Dm in,Dmax,V40,V50 and V60 for pharyngeal constrictor muscle were 52.29±3.92 Gy,36.95±3.08 Gy,72.72±2.52 Gy,78.70±1.59%,48.00±1.35%,33.30±2.34%;The mean values of Dmean,Dmin and Dmax for superior constrictor muscle(SCM)were 63.49±3.99 Gy,45.82±1.91 Gy and 72.17±4.54Gy;The mean values of Dme an,Dmin and Dmax for middle constrictor muscle(MCM)were 46.90±3.89 Gy,38.33±3.58 Gy and 63.60±5.00Gy;The mean values of Dmean,Dmin and Dmax for superior constrictor muscle(SCM)were 41.83±3.43 Gy,37.54±3.34 Gy and 53.64±2.53 Gy.The DVH parameters in the group of DF: The mean values of Dme an,Dmin,Dmax,V40,V50 and V60 for pharyngeal constrictor muscle were 42.92±2.43 Gy,35.95±3.29 Gy,64.19±2.52 Gy,49.67±1.62%,25.00±4.92%,11.00±1.43%;The mean values of Dmean,Dmin and Dmax for superior constrictor muscl e(SCM)were 48.98±1.82 Gy,39.02±2.89 Gy,63.46±4.57Gy;The mean values of Dmean,Dmin and Dmax for middle constrictor muscle(MCM)were 42.55±3.91 Gy,37.51±3.22 Gy and 57.78±2.52Gy;The mean values of Dmean,Dmin and D max for superior constrictor muscle(SCM)were 39.91±1.91 Gy,34.82±3.20 Gy a nd 53.13±2.55 Gy.4.Comparison of the dosimetric parameters of PCM in two groups4.1 Dmean,Dmin,Dmax,V40,V50,V60 for PCMThe mean values of Dmean,V40,V50 and V60 for PCM in DY group were greater than that in DF group,and the differences were statistically significant.4.2 Dmean,Dmin,Dmax for SCMThe mean values of Dmean and Dmax for SCM in DY group were greater than DF group,and the differences were statistically significant.4.3 Dmean,Dmin,Dmax for MCMThe mean values of Dmean and Dmax for MCM in DY group were greater than DF group,and the differences were statistically significant.4.4 Dmean,Dmin,Dmax for ICMThere wERE no significant differences between the mean values of Dmean,Dmin and Dmax for ICM in two groups.Conclusions:1.Patients with nasopharyngeal carcinoma treated with IMRT have a favorab le prognosis,but still induce different levels of late adverse reactions;2.The incidence of RISD in NPC was associated with N stage;3.The mean values of Dmean,V40,V50 and V60 for PCM in DF group w ere all lesser than that in DY group and the differences were statistically signific ant.Reducing the dose irradiated to pharyngeal constrictor muscle is beneficial to alleviate radiation-induced swallowing dysfunction(RISD);4.The differences of the mean values of Dmean and Dmax for SCM and M CM were statistically significant between the two groups.Therefore reducing the dose irradiated to SCM and MCM in patients with nasopharyngeal carcinoma tr eated with IMRT has an important significance to the optimization for Intensitymodulated radiation therapy(IMRT). |
PDF Full Text Request