口咽癌VMAT与HT的放射性口腔黏膜炎发生率及剂量学研究

目的通过对比口咽癌患者容积旋转调强放疗(Volume-Modulated Arc Radiotherapy,VMAT)和螺旋断层调强放疗(Helical Tomotherapy,HT)计划剂量学的差异及放射性口腔黏膜炎发生率的不同,探讨不同放疗技术的安全性及优势。方法回顾性选择2016年6月至2018年6月我院进行VMAT和HT的患者各22例,两组临床资料无差异,根据剂量体积直方图评价两组计划靶区的D_1%、D_5%、D_95%、D_99%、适形度指数(Conformity Index,CI)、均匀性指数(Homogeneity Index,HI)和口腔的体积、最大剂量D_max、最小剂量D_min、平均剂量D_mean、V₁₅、V₂₀、V₂₅、V₃₀、V₃₅、V₄₀、V₄₅、V₅₀、V₅₅、V₆₀,观察比较两组患者放疗期间急性口腔黏膜炎发生率和严重程度。结果HT组原发肿瘤(pGTVnx)、高危亚临床病灶(PTV1)和低危亚临床病灶(PTV2)的D_99%高于VAMT组(F=4.328、2.875、3.765,P<0.05),CI更接近1(F=-2.245、-1.986、-1.867,P<0.05);靶区的D_1%、D_5%、D_95%和HI差异均无统计学意义(P>0.05)。HT组口腔的D_min值大于VMAT组(95%CI:0.001~0.003,P<0.05),V₃₅显著低于VMAT组(95%CI:0.042~0.057,P<0.05);两组口腔的V₁₅、V₂₀、V₂₅、V₃₀、V₃₅、V₄₀、V₄₅、V₅₀、V₅₅、V₆₀差异均无统计学差异(P>0.05)。HT组治疗时间高于VMAT组(F=7.672,P=0.009);但≥3级口腔黏膜炎发生率更低(P=0.019)。结论VMAT与HT技术均能满足口咽癌放疗剂量要求,HT计划靶区的CI更好,靶区剂量明显提高,在减少口腔V₃₅方面更有优势,虽然治疗时间略长,但能减少≥3级放射性口腔黏膜炎的发生率。

Incidence and Dosimetry Comparison of Radiotherapy-induced Oral Mucositis in Patients with Oropharyngeal Carcinoma Treated with VMAT and HT

Objective To explore the safety and advantages of different radiotherapy techniques by comparing the differences in dosimetry and incidence of radiotherapy-induced oral mucositis between volume-modulated arc radiotherapy(VMAT)and helical tomotherapy(HT)plans in patients with oropharyngeal carcinoma.Methods A total of 22 patients with oropharyngeal carcinoma who underwent VMAT and HT from June 2016 to June 2018 were respectively selected,and there was no difference in clinical data between the two groups.The D_1%,D_5%,D_95%,D_99%and D_99%,conformity index(CI)of the target volume,homogeneity index(HI)of the target volume,and the volume of oral cavity,D_max,D_min,D_mean,V₁₅,V₂₀,V₂₅,V₃₀,V₃₅,V₄₀,V₄₅,V₅₀,V₅₅,V₆₀ were evaluated between the two groups according to the dose-volume histogram.The incidence and severity of radiotherapy-induced oral mucositis were also observed.Results The D_99% of pGTVnx,PTV1 and PTV2 in the HT group were higher than those in the VAMT group(F=4.328,2.875,3.765,P<0.05),and the CI was closer to 1(F=-2.245,-1.986,-1.867,P<0.05);but there was no statistically difference in D_1%,D_5%,D_95% and HI of the target area(P>0.05).The Dmin of the oral cavity in the HT group was greater than that of the VMAT group(95%CI:0.001~0.003,P<0.05),and V₃₅ was significantly lower than that of VMAT group(95%CI:0.042~0.057,P<0.05);but there was no statistically difference in V₁₅,V₂₀,V₂₅,V₃₀,V₃₅,V₄₀,V₄₅,V₅₀,V₅₅,V₆₀ of the oral cavity(P>0.05).The treatment time of the HT group was longer than that of the VMAT group(F=7.672,P=0.009);however,the incidence of≥3 grade oral mucositis was lower(P=0.019).Conclusion Both VMAT and HT can meet the radiotherapy dose requirements of oropharyngeal carcinoma.The HT plan has a better CI,higher target dose and lower V₃₅ of oral cavity.Although the treatment time was slightly longer,HT can reduce the incidence of≥3 grade radiotherapy-induced oral mucositis.