Clinical Observation of Hypofractionated Simultaneous Integrated Boost Radiotherapy in Breast-Conserving Surgery

Abstract

Comparing the skin toxicity, cosmetic effect, myelosuppression and other adverse reactions between hypofractionated simultaneous integrated boost (HF-SIB) and conventional fractionated (CF) radiotherapy for breast cancer patients after breast-conserving surgery, to evaluate the short-term efficacy and safety of HF-SIB. A total of 236 early breast cancer patients received radiotherapy after breast-conserving surgery were prospectively enrolled in this study. All patients divided into two groups according to the dose of radiotherapy. HF-SIB included 126 patients and the dose of whole-breast radiation reach to 42.56Gy in 16 fractions and simultaneously tumor bed boost to 48Gy in 16 fractions, which course of radiotherapy was 22 days. The 110 patients of CF group received whole breast radiation to 50Gy in 25 fractions and followed by tumor bed boost to 10Gy in 5 fractions, which course of radiotherapy was 40 days. The indexes such as acute skin reaction, late skin toxicity, myelosuppression, cosmetic effect and radiation pneumonia were recorded and analyzed by Rank sum test and chi-square test. After a median follow-up of 14.6 months (7-18 months), HF-SIB group have no cases of recurrence (0/126) and the survival rate was 100% (126/126). After a median follow-up of 33.4 month (25-45 months) in CF group, the recurrence rate was 3.6% (4/110) and the 2-year survival rate was 100% (110/ 110). The incidence of acute skin reaction of grade 1, grade 2 and grade 3 in HF-SIB group was 52.7%, 15.8% and 2.6%, respectively and that in CF group is 50%, 25% and 5%. The incidence of late skin reaction in grade 1 and grade 2 was 25% and 5.2% in HF-SIB group and 20% and 3.3% in CF group respectively. The excellent and good rate of cosmetic effect of HF-SIB group and CF group at an interval of six months after radiotherapy was 97.4% vs 90%, and that of one year after radiotherapy was 93.1% vs 86.7%. The incidence of grade 1 and 2 radiation pneumonia in the HF-SIB group was 6.6% and 3.9%, while that in the CF group was 5.0% and 1.7%, respectively. There was no statistical difference in skin toxicity, cosmetic effect and radiation pneumonia between the two groups. In terms of myelosuppression, the HF-SIB group was better than the CF group. There was no significant difference in age, chemotherapy, fractionated dose and posture on skin reaction and cosmetic effect, but there was a correlation between the volume of breast and the incidence of skin reaction. The evaluation of clinic effect in HF-SIB group was not inferior to that in CF group, and there was no significant difference between HF-SIB group and CF group in terms of skin reaction and cosmetic effect. The degree of myelosuppression in HF-SIB group was lower than that in CF group. HF-SIB group can shorten the treatment time and reduce medical expenses. Moreover, the short-term effect was similar to that of CF group, so it can be used as one of the radiotherapy modes for early breast cancer patients after breast-conserving surgery.