ABSTRACT
Objective To analyze the recurrence of breast cancer without use of chest wall bolus during adjuvant intensity modulated radiotherapy after modified radical mastectomy, so as to investigate the necessity of bolus use. Methods A total of 218 patients undergoing adjuvant intensity modulated radiotherapy after modified radical mastectomy during the period from January 2013 to June 2019 were enrolled as the study subjects. The chest wall bolus was not used during the whole period of radiotherapy after modified radical mastectomy, and the recurrence of breast cancer in the chest wall was analyzed after radiotherapy. Results The post-surgical follow-up through outpatient records, inpatients records, local residents’ health system and telephone was performed until June 31, 2021. The proportion of follow-up was 100%, and the mean follow-up period was 48.9 months. There were three cases with breast cancer recurrence in the chest wall, including one case with recurrence in the chest wall alone and two cases with recurrence in the chest wall and regional lymph nodes, and the overall recurrence of breast cancer was 1.4% in the chest wall. Among the 3 cases with breast cancer recurrence in the chest wall, there were two cases with N3 stage and positive for HER2, and one triple-negative breast cancer case, and all three cases developed distal metastases upon local recurrence. Among 218 study subjects, there were 5 cases with grade Ⅰ radioactive skin reaction, 3 cases with grade Ⅱ radioactive skin reaction, and no grade Ⅲ or Ⅳ radioactive skin reaction occurred. In addition, no grade Ⅲ or Ⅳ acute radioactive injury was seen in the chest wall skin among the 218 study subjects. Conclusion No use of chest wall bolus may be considered during adjuvant intensity modulated radiotherapy after modified radical mastectomy in presence of systemic therapy if tumor invasion into skin is not observed prior to therapy.