| Objective: To compare acute radiation esophagitis and acute radiation pneumonia between VMAT and s IMRT in breast cancer patients after modified radical mastectomy,analyze the correlation between clinical and dosimetric characteristics and them,and explore the influencing factors of them.Methods: Retrospective analysis was performed on female patients undergoing intensity modulated radiotherapy after modified radical mastectomy in department of radiotherapy in our hospital from September 1,2018 to October 31,2020.Patients were divided into the VMAT group and the s IMRT group according to the radiotherapy technique received by them.All of them received 6MV-X-ray radiation from the Varian Trilogy linear accelerator.Prescribed dose to the planning target volume(PTV)was 45-50 Gy in 23-25 fractions(1.8-2.0Gy/f).Radiotherapy was given once a day,5 times a week.The goal of the prescription was that 95% of the volume received 95% of the prescribed dose.Follow-up was performed by single blind method.Patients were followed up by two other physicians who had been systematically trained and did not know which type of the radiotherapy technique were received by the patients 1 month and 3 months after the start of radiotherapy by reviewing the medical records and imaging data,telephone interviews and outpatient.Acute radiotoxicities were evaluated by RTOG grading standard.Chi-square test was used to analyze the occurrence of acute radiation esophagitis and acute radiation pneumonia in the two groups.Then the correlation between clinical and dosimetric characteristics and them was analyzed.Univariate analysis was performed by One-way ANOVA(if it is measurement data)or chi square test(if it is counting data),and multivariate analysis was performed by binary logistic regression analysis to explore the influential factors of acute radiation esophagitis and acute radiation pneumonia of intensity modulated radiotherapy after modified radical mastectomy for breast cancer.Results: A total of 132 patients were collected,including 87 patients in the VMAT group and 45 patients in the s IMRT group.Seven patients were lost to follow-up in the VMAT group and 4 patients in the SIMRT group.A total of 121 patients were finally enrolled,including 80 patients in the VMAT group and 41 patients in the s IMRT group.The incidence of grade 1 and above acute radiation esophagitis in the VMAT group and the s IMRT group was 16.25%(13/80)and 34.15%(14/41)respectively,which in the VMAT group was significantly lower than that in the s IMRT group(P=0.036).The incidence of grade 1 and above acute radiation pneumonia in the VMAT group and the s IMRT group was 12.5%(10/80)and26.83%(11/41)respectively,which in the VMAT group was significantly lower than that in the s IMRT group(P=0.015).Univariate analysis showed that acute radiation esophagitis was significantly correlated with Dmean(F=26.761,P<0.001),D50%(F=38.993,P<0.001),V30(F=53.898,P<0.001)and V45(F=9.969,P<0.001)of esophagus,and acute radiation pneumonia was significantly correlated with V10(F=3.711,P=0.014),V13(F=2.859,P=0.040),V15(F=2.745,P=0.046),V20(F=2.867,P=0.040),V25(F=3.089,P=0.030),V30(F=3.328,P=0.022)of the breast cancer ipsilateral lung and chemotherapy cycle before radiotherapy.Multivariate analysis suggested that esophageal V30(OR=1.140,95%CI :1.026-1.267,P=0.015)was a risk factor for acute radiation esophagitis after intensity modulated radiation therapy after modified radical mastectomy.In addition,V10(OR=1.328,95%CI:1.015-1.737,P=0.0395)and V20(OR=1.666,95%CI:1.086-2.557,P=0.019)of the breast cancer ipsilateral lung were risk factors for acute radiation pneumonia after intensity modulated radiation therapy after modified radical mastectomy.Conclusions:1.Compared with s IMRT,VMAT can significantly reduce the incidence of acute radiation esophagitis and acute radiation pneumonia after modified radical mastectomy in breast cancer patients and has more advantages in the protection of esophagus and lung.2.Esophageal V30 is a risk factor for acute radiation esophagitis after intensity modulated radiation therapy after modified radical mastectomy in breast cancer patients,which can be used as a predictive factor for the occurrence of acute radiation esophagitis.3.V10 and V20 of the breast cancer ipsilateral lung are risk factors for acute radiation pneumonia after intensity modulated radiation therapy after modified radical mastectomy in breast cancer patients,which can be used as a predictive factor for the occurrence of acute radiation pneumonia. |
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