A Comparison Of Short-term Clinical Observation And Dosimetry For Hypofractionated Radiotherapy And Conventional Fractionated Radiotherapy Of Early-breast Cancer After Breast-conserving Surgery

Objective: To compare the short-term adverse reactions,cosmetic effects,and radiological exposure to target and endangered organs in patients with early-stage b reast cancer undergoing hypofractionated radiotherapy and conventional fractionated radiotherapy.Methods:A total of 100 breast-conserving patients received full-intensit y intensity radiotherapy after breast-conserving surgery were collected from Depart ment of Breast Radiation Oncology,Xinjiang Medical University from November 2014 to December 2015.The single dose of 50 cases of hypofractionated radiothera py was 2.66 Gy,a total of 16 times;50 cases of conventional fractionated single dose was 2Gy,a total of 25 times.A total of 32 cases of left breast cancer in tw o groups were compared between the two groups in terms of target area and the d ose distribution characteristics of the endangered organs.Results:(1)The median f ollow-up of 25 months,all patients survival rate and the control rate were 100%,t wo groups of 0,1,2 grade acute skin reaction and cosmetic evaluation,the degree o f bone marrow suppression differences were not statistically Significance(P>0.05).(2)There was no significant difference between the two groups in the number of cases with acute radiation pneumonitis(1 grade)and in 2 cases(no grade 2 and >grade 2).(3)The target coverage of the two groups were satisfactory,but the V105,Dmax and Dmean of the planning target area in the hypofractionated radiotherap y group were significantly higher than those in the conventional group(P<0.05).(4)There was no significant difference in Dmin,Dmean,V5,V10,V20,and V30 bet ween the two groups of lungs(P>0.05).However,Dmax and V40 of the hypofract ionated radiotherapy were higher the two groups.The difference was statistically si gnificant(P<0.05).(5)There were no significant differences in Dmin,Dmean,andV10 in the heart between the two groups(P>0.05).However,Dmax,V20,V30,an d V40 in the heart of the hypofractionated radiotherapy group were all significantly higher(P<0.05).(6)There was no significant difference in Dmax,Dmin,Dmean,V5,V10 in the contralateral breast between the two groups(P>0.05).Conclusions:(1)The results of hypofractionated radiotherapy after breast-conserving surgery are similar to those of conventional fractionated radiotherapy.The bone marrow suppr ession reaction,acute radiation-induced skin reaction and cosmetic evaluation are si milar.(2)In this study,under the same limiting dose conditions,the hypofractionate d radiotherapy program in this study increased the volume of irradiation in the tar get area and in the high dose area of lung tissue and cardiac area.However,withi n the limits of normal restriction,the hypofractionated radiotherapy group did not i ncrease the proportion of radiation-induced lung injury within short-term follow-up.