Protection Of Normal Tissue By Individualized Stent Based On 3D Printed In Radiotherapy For Head And Neck Cancer

Part one Dosimetric analysis of 3D printed personalized oral stents in target areas and organs at risk in radiotherapy for head and neck cancerObjective:To compare and analyze the dosimetric differences between 3D printed personalized oral stents and traditional corked oral stents in the target area and perioral organs at risk in radiotherapy for head and neck cancer,and to provide a theoretical basis for their clinical application in reducing the occurrence of adverse effects such as acute radiotherapy-induced oral mucositis,xerostomia and oropharyngeal mucosal pain.Methods:21 patients with head and neck cancer who met the inclusion criteria and were admitted to the Oncology Department of the Affiliated Hospital of North Sichuan Medical College from April 2021 to November 2021 were selected,and Self-control method was used.The enrolled patients first wore 3D printed personalized oral stents for their radiotherapy plans,followed by conventional corked oral stents for their radiotherapy plans.SPSS 25.0 statistical software was used to analyze the differences in target area dose(Ci,HI)and the dose of the organs at risk(lip,buccal mucosa,submandibular gland,parotid gland,lens,brainstem,spinal cord Dmax,Dmean)between the two groups,and with P<0.05 judged to be statistically significant.Results:1.Comparison of target dose parameters:HI(0.181±0.1 16 VS0.204±0.115)and CI(0.686±0.115 VS 0.690±0.100)were not significantly different between experimental and control groups,and the comparison was not statistically significant(P>0.05).2.Comparison of dose parameters for organs at risk:In the experimental group,upper lip Dmax(40.9± 19.3 Gy VS 43.2 ± 18.2 Gy),upper lip Dmean(20.0 ± 11.3 Gy VS 23.1 ±11.8 Gy),ipsilateral buccal mucosa Dmax(50.8±12.6 Gy VS 53.7±12.2 Gy),ipsilateral buccal mucosa Dmean(35.6± 18.3 Gy VS 37.8± 17.1 Gy),ipsilateral crystal Dmax(1.2 ± 1.3Gy VS 1.5± 1.3 Gy),ipsilateral crystal Dmean(1.0±1.0Gy VS 1.2 ± 1.0 Gy),contralateral crystal Dmax(1.2 ± 1.8Gy VS 1.6±2.3 Gy),were significantly lower than those of the control group,with P of 0.014,0.000,0.009,0.033,0.002,0.003,and 0.010,respectively,and the differences were statistically significant;the experimental groups’ Dmax and Dmean of the lower lip,contralateralbuccal mucosa,bilateral parotid glands,contralateral submandibular gland,and Dmean of the contralateral crystal,spinal cord,and brainstem in the experimental group showed a decreasing trend compared with the control group,but the differences were not statistically significant,and the P were greater than 0.05.Conclusions:1.The new 3D-printed personalized oral stent designed in this study had a small effect on the dose distribution in the target area compared with the traditional corked oral stent,and the difference was not statistically significant(P>0.05).Better uniformity and conformability were obtained,which is feasible for clinical application.2.The new 3D printed personalized oral stent designed in this study significantly reduced Dmax and Dmean in the upper lip,ipsilateral buccal mucosa and ipsilateral crystal,and Dmax in the contralateral crystal.Although the analysis of the difference in irradiated dosebetween the two groups of lower lip,contralateral buccal mucosa,bilateral parotid,and contralateral submandibular gland was not statistically significant,the experimental group showed a trend of reduction.It provides a theoretical basis for 3D printing personalized oral stent in radiotherapy of head and neck malignancies.Part two Clinical observation of acute adverse effects of 3D printed personalized oral stents in radiotherapy for head and neck cancerObjective:To compare and analyze the occurrence and severity of radiotherapy-related acute RTOM,xerostomia and painful oropharyngeal mucosal injury between 3D printed personalized oral stents and traditional corked oral stents in radiotherapy for head and neck malignancies,and to explore new ways to reduce radiotherapy-related adverse effects in clinical work.Methods:Patients with head and neck cancer who met the inclusion criteria and were admitted to the Oncology Department of the Affiliated Hospital of North Sichuan Medical College from May 2020 to November 2021 were selected.Among them,30 patients in the control group(wearing traditional cork oral stents during radiotherapy)and 28 patients in the experimental group(wearing 3D printed personalized oral stents during radiotherapy).The clinical data such as age,gender,disease type,pathological type,tumor stage and concurrent chemotherapy were collected from the two groups,and the occurrence and severity of RTOM,xerostomia and oropharyngeal mucosal pain were compared between the two groups before,weekly and at the end of radiotherapy,and the completion of radiotherapy was compared and analyzed.SPSS 25.0 statistical software was used for statistical analysis,and the measurement data were expressed as mean ±standard deviation(X±s),and the comparison between the two groups was analyzed by paired t-test or repeated measures;the count data were expressed as rate(%),and the χ2-test or Fisher exact probability method was used for the comparison between the two groups.P<0.05 was considered a statistically significant difference.Results:1.There were no statistically significant differences between the experimental group and the control group in terms of age,gender,T stage,N stage,M stage,TNM stage,disease type,pathological type and whether synchronous chemotherapy was administered,and the P values were greater than 0.05.The two groups were comparable.2.Comparing the treatment completion degree of the two groups,the results showed that all patients in the experimental group completed the radiotherapy treatment plan,while 4 patients in the control group did not complete the radiotherapy treatment plan,and the treatment completion degree of the experimental group tended to be higher than that of the control group,but the difference was:not statistically significant(P>0.05).3.All patients in the group did not suffer from mucositis,xerostomia and oropharyngeal mucosal pain before radiotherapy.Weekly follow-up during and at the end of radiotherapy,patients in both groups developed RTOM,xerostomia and oropharyngeal mucosal pain.The cases of RTOM from grade I to grade IV in the experimental group was 11,10,7 and 0,respectively,and the cases of acute RTOM from grade I to grade IV in the control group was 1,11,15 and 3,respectively.The severity of RTOM in the experimental group was significantly lower than that in the control group,and the difference was statistically significant(P<0.05).4.Comparing the degree of oropharyngeal mucosal pain during and at the end of radiotherapy between the two groups,the results showed that the degree of pain in the experimental group was significantly lower than that in the control group,and the difference was statistically significant(P<0.05).5.Xerostomia appeared in both groups during radiotherapy.It appeared in the experimental group from the second week of radiotherapy and in the control group from the first week of radiotherapy.It peaked in the fourth week in both groups and gradually decreased afterwards.Xerostomia in the experimental group were lower than those in the control group,and the difference was statistically significant(P<0.05).Conclusions:Compared with the traditional cork oral stent,wearing the new 3D-printed personalized oral stent in radiotherapy for head and neck cancer patients can effectively reduce the occurrence and severity of acute RTOM,xerostomia and oropharyngeal mucosal injury pain associated with radiotherapy,and can improve the treatment completion of patients,which is worthy of clinical promotion and application.