Discussion On The Curative Effect And Improved Location Method Of Hypofractionation And Conventional Radiotherapy After Breast Conserving Surgery

ObjectivesTo compare and analyze the adverse reactions and cosmetic effects of patients with breast cancer after breast conserving surgery treated with HF-WBI and CF-WBI based on body membrane fenestration,and to explore the improved localization method.Methods163 patients with breast cancer after breast conserving surgery in our hospital from October 2018 to August 2020 were randomly divided into two groups: HF-WBI group(n=82 cases)was given 42.4 Gy/16 fractions(2.65 Gy/fraction);CF-WBI group(n = 81 cases)was given 50 Gy/25 fractions(2.0 Gy/fraction);all patients were given10 Gy/5 fractions of sequential tumor bed X-ray after whole breast irradiation.All patients were positioned with thermoplastic body membrane,and the body membrane above the breast was cut off along the root of the affected breast.The main radiotherapy related adverse reactions,cosmetic effect,treatment time,treatment cost,local control rate and recurrence rate of the two groups were observed,and the positioning error of fenestration positioning method after breast conserving surgery was analyzed.Results1.Acute skin reaction: there was no acute radiation skin reaction of grade 3 or above in all patients,the acute skin reaction within 3 months in HF-WBI group was significantly lower than that in CF-WBI group(40.24% vs 71.60%,P<0.05).There was no grade 2 or above late skin reaction in all patients,and the difference was not statistically significant(17.07% vs 24.69%,P>0.05).2.Bone marrow suppression: all patients were regularly reviewed before treatment,during treatment and at the end of treatment.There was no significant difference in the incidence of leucopenia and thrombocytopenia between the two groups(P>0.05).3.Radiation pneumonitis: there was no acute radiation pneumonitis of grade 2 or above,HF-WBI group was slightly better than that of CF-WBI group,but the difference was not statistically significant(10.98% vs 7.41%,P>0.05).There was no late radiation pneumonitis,shortness of breath or precordial discomfort.4.The excellent and good rate of cosmetic effect: at the end of radiotherapy,3months and 6 months after radiotherapy,the cosmetic effect of HF-WBI group was better than that of CF-WBI group,but the difference was not statistically significant(P>0.05)5.Treatment cost and time: compared with CF-WBI group,the treatment time of HF-WBI group was reduced by about 16 days,and the cost was saved by about10000 yuan,the differences were statistically significant(P<0.05).6.Positioning error: the systematic error values of all patients in the left and right(X),head and foot(Y),abdominal and back(Z)directions were(2.26±0.67)mm、(2.97±0.61)mm、(2.48±0.72),respectively.The proportion of positioning error distribution in the X,Y,Z directions was: 74.17% was≤3mm,20.44% was between3~5mm,94.61% was≤5mm,with high positioning accuracy and good stability Sex.7.Analysis of the positioning error: the difference of the positioning error in the X and Z directions of the patients of the same age group was statistically significant(P < 0.05),there was no significant difference in Y direction(P>0.05);the results showed that the difference of the setting position in Y direction was correlated with the age of patients with age≥60 years old(P<0.05).There was significant difference in Z direction of positioning error among patients with different BMI(P<0.05),but there was no significant difference in the X and Y directions(P > 0.05).BMI≤24kg/m2 was correlated with Y direction(P<0.05),and the setting error of BMI >24kg/m2 was correlated with BMI value in Z direction(P<0.05).8.Local control rate and survival rate: all patients successfully completed radiotherapy.Up to December 2020,the follow-up rate was 100%,the median follow-up time was 14 months.Conclusion1.Based on the body membrane fenestration positioning method of breast cancer after breast conserving surgery hypofractionated radiotherapy is feasible,can significantly reduce the acute radiation skin reaction,and does not increase the adverse reactions of radiotherapy.It can improve the use efficiency of radiotherapy equipment,accelerate the turnover speed of hospital,and save social medical insurance resources2.After breast conserving surgery,thermoplastic membrane fenestration was used for positioning with high accuracy,good stability,and has practical promotion value,elderly patients and obese patients need to focus on positioning.