Dosimetric Comparison Of TOMO,VMAT,IMRT In Radiotherapy For Non-small Cell Lung Cancer And Esophageal Cancer And Comparative Study Of Radiation Dose For Locally Advanced Esophageal Cancer

Part ?: Dosimetric comparison of the helical tomotherapy(TOMO),intensity-modulated radiotherapy(IMRT)and volumetric-modulated arc therapy(VMAT)in radical radiotherapy for non-small cell lung cancerObjective: compare dosimetric parameters of three different modern radiation techniques in radical radiotherapy for locally advanced non-small cell lung cancer.Methods: A total of 30 patients with pathologically confirmed NSCLC were included and three radiation treatment plans for helical tomotherapy(TOMO),intensity-modulated radiotherapy(IMRT)and volumetric-modulated arc therapy(VMAT)were designed for each patient.All patients received the total prescription dose of 60 Gy in 30 fractions to the planning target volume(PTV).Conformity index(CI),heterogeneity index(HI),D1,D2,D50,D95,D98,D99 and V95,V100,V105 of PTV was calculated for each case.The mean dose,V5,V10,V20,V30,V40 and V50 of total lung and heart,and maximum dose(Dmax)to spinal cord and esophagus were recorded as well.Results: The mean CI was significantly superior by VMAT compared to either TOMO or IMRT techniques(P=0.013,0.001,respectively).The mean HI was also significantly better by VAMT and IMRT compared to TOMO(P=0.002,0.003,respectively).The mean dose to PTV by VMAT was 62.41 Gy,which was significantly decreased compared to plans by TOMO(63.37 Gy,P=0.000)and IMRT 62.68 Gy,P=0.047).MLD,V5,V10,V40,and V50 for the total lung were similar by all three techniques.Mean V20 and V30 of lung were significantly reduced by TOMO plan compared to IMRT plan(V20: 21.80% vs.24.24%,P=0.019;V30: 15.14% vs.16.71%,P=0.029).The heart was spared significantly by IMRT plan compared to TOMO in terms of MHD,V5,V10,and V20(P<0.05).The mean maximum doses to esophagus and spinal cord were comparable among three radiation techniques(P>0.05).Subgroup analysis showed that TOMO created the reduction of lung V20 at the cost of increasing V5 spread to normal lung in centrally located lung lesions.In larger target volume,VMAT provided the optimal technique compared with the other two plan,regardless of dose distribution or sparing the normal heart.Conclusion: VMAT plan achieved optimal conformal and homogeneous dose distribution in terms of PTV.TOMO plan showed slightly advantage in reducing the sparing of total normal lung,mainly in V20 and V30,but at the cost that more low-dose area spread to normal lung and more radiation doses to the heart.VMAT seems to be the optimal treatment planning technique in the dosimetric comparison with TOMO and IMRT.Part ?: Dosimetric comparison of the helical tomotherapy(TOMO),intensity-modulated radiotherapy(IMRT)and volumetric-modulated arc therapy(VMAT)in radical radiotherapy for esophageal cancerObjective: compare dosimetric parameters of three different modern radiation techniques in radical radiotherapy for locally advanced esophageal cancer.Methods: A total of 25 patients with pathologically confirmed esophageal squamous cell carcinoma were included and three radiation treatment plans for helical tomotherapy(TOMO),intensity-modulated radiotherapy(IMRT)and volumetric-modulated arc therapy(VMAT)were designed for each patient.All patients received the total prescription dose of 60 Gy in 30 fractions to the planning target volume(PTV).Conformity index(CI),heterogeneity index(HI),D1,D2,D50,D95,D98,D99 and V95,V100,V105 of PTV was calculated for each case.The mean dose,V5,V10,V20,V30,V40 and V50 of total lung and heart,and maximum dose(Dmax)to spinal cord were recorded as well.Results: Compared with TOMO and IMRT,VMAT showed higher CI and lower HI in absolute value,and CI was worse in IMRT than TOMO(P=0.016)and VMAT(P=0.010).There was no significant difference in HI among three radiotherapy techniques.The dosimetric parameters of TOMO in normal lung tissue were significantly better than that of VMAT and IMRT,especially in V20 and V30.However,compared with VMAT,TOMO seems to be at a disadvantage(P<0.05)in the low-dose area of the heart(V5,V10 and V20).The highest dose of spinal cord(38.24�3.72)in TOMO plan was significantly better than that of the VMAT(39.88�3.27,P=0.004)and IMRT plan(41.09�3.18,P=0.000).Subgroup analysis showed that VMAT was superior to TOMO and IMRT plans in CI and HI,especially HI significantly better than TOMO(P=0.029)and IMRT(P=0.013)for patients with cervical and upper thoracic cancer.TOMO and VMAT were significantly better than IMRT plan in lung MLD,V20 and V30(P<0.05).TOMO was significantly superior to VMAT(P=0.043)and IMRT(P=0.027)at the highest dose of the spinal cord.For the patients with middle and lower thoracic cancer,TOMO,VMAT and IMRT had no statistically significant differences in CI and HI.The IMRT plan is inferior to TOMO and VMAT in the lung MLD,V10,V20,and V30(P<0.05),while TOMO is slightly higher in the low-dose area of the heart than the VMAT and IMRT plans.TOMO was significantly superior to VMAT(P=0.004)and IMRT(P=0.000)at the highest dose of the spinal cord.There was no statistically significant difference among TOMO,VMAT and IMRT in CI,HI,and heart sparing in small tumors(less than 4cm)(P<0.05).The IMRT plan is inferior to TOMO and VMAT plan at MLD,lung V10,V20,V30 and the highest dose of spinal cord(P<0.05).In the large tumor(> 4cm)subgroup,there was no statistically significant difference among TOMO,VMAT and IMRT in CI,HI and heart sparing(P>0.05).The IMRT plan is inferior to TOMO and VMAT plan at MLD,lung V20,V30 and the highest dose of spinal cord(P<0.05).There was no statistically significant difference in CI,HI,and heart sparing among TOMO,VMAT and IMRT in the early stage(IIa,IIb)subgroups(P<0.05).The IMRT plan is inferior to TOMO and VMAT plan at lung V20,V30 and the highest dose of spinal cord(P<0.05).In the late stage(III,IVa)subgroup,the IMRT plan was significantly inferior to TOMO(P=0.009)and VMAT(P=0.012)in CI,while VMAT was significantly superior to TOMO(P=0.011)and IMRT(P=0.001)in HI.TOMO was significantly superior to VMAT and IMRT at MLD,lung V5,V20,V30 and the highest dose of spinal cord(P<0.05).There was no statistically significant difference in heart sparing.Conclusion: the VMAT plan is better than TOMO and IMRT in terms of the conformal degree and dose uniformity of the target volume.TOMO seems significantly better than VMAT and IMRT in reducing normal lung tissue(mainly in V20 and V30)and in the highest doses of the spinal cord.As to the physical dosimetric parameters,the IMRT is inferior to TOMO and VMAT in the protection of normal tissue tolerance.Part ?: A multi-center,randomized,prospective study evaluating the optimal radiation dose of definitive concurrent chemoradiation for inoperable esophageal squamous cell carcinomaObjective: To determine the optimal radiation dose for definitive concurrent chemoradiation in esophageal squamous cell carcinoma(ESCC)using modern radiation technology.Methods: Pathologically confirmed ESCC patients with stage IIA-IVA were randomized into high-dose(60Gy)and low-dose group(50Gy).The total radiation doses were delivered 2Gy per fraction,5 fractions per week,by intensity-modulated radiation therapy(IMRT).Concurrent weekly chemotherapy and 2 cycles consolidation chemotherapy were administrated.The primary endpoint was local/regional progression-free survival(LRPFS).Results: From April 2013 to May 2017,305 patients were randomized into the high-dose(n=152)and low-dose group(n=153).There were no significant differences in gender,age,KPS,clinical stage,location,the length of tumor between the two groups.The radiotherapy completion rate was 87.5%(133/152)and 95.4%(146/153)in the high and low dose groups respectively(P=0.002).The concurrent weekly chemotherapy completion of receiving 5,4,?3 weeks drugs were 61.2%(93/152)?66.7%(102/153);21.1%(32/152)?20.9%(32/153);17.8%(27/152)?12.4%(19/153)(P=0.406).There was no significantly difference in the completion of consolidation chemotherapy(P=0.207).At a median follow-up of 14.4 months(1.3-51.4 months),the 1,2-year LRPFS rate was 85.8%?74.4% and 85.1%?78.4%(HR:1.27,95%CI: 0.62-2.60,P=0.676).The 1,2-year PFS and OS rate was 78.6%?67.6%,76.9%?67.7%(HR:0.95?95%CI:0.55-1.65,P=0.859);84.6%?67.3%,86.4%?72.2%(HR:1.24,95%CI:0.64-2.38,P=0.981).The treatment toxicity equal to or greater than grade 3 included leukopenia;radiation esophagitis and pneumonitis.There were no significant differences between the two groups.Conclusions: There was no difference towards LPSFS and toxicity between high-dose(60Gy)and low-dose(50Gy)group.A total radiation dose of 50 Gy was recommended for definitive concurrent chemoradiation in ESCC.