Tomotherapy in synchronous and metachronous bilateral breast cancer: Clinical experience.

PURPOSE OF STUDY: The objective of this research is to present our firsthand experience and provide up-to-date data for the further study of cases involving simultaneous breast irradiation using helical Tomotherapy, ©Accuray Inc.

METHODS: The radical treatment options for bilateral breast cancer are surgery, chemotherapy, and radiation therapy. Being that radiotherapy for bilateral breast cancer is challenging due to limitations in the geometry of modern radiotherapy equipment, helical Tomotherapy was chosen as an appropriate technique of irradiation. The retrospective review focused on the records of patients who underwent bilateral irradiation of the breast or chest wall and regional lymph nodes using helical Tomotherapy.

RESULTS: Only four patients with bilateral breast cancer completed a radiation therapy course in our center from 2018 to 2023. Two patients underwent radical mastectomy with lymph node dissection on both sides before irradiation. For the other two patients, radical mastectomy was done after neoadjuvant chemotherapy. Acute radiation toxicity scoring was based on Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Only mild adverse effects, such as general weakness and slight skin irritation below Grade 3, were observed, with no instances of skin swelling, dryness, or pigmentation noted. Evaluation of late complications revealed tissue fibrosis in the area of the internal mammary nodes and respiratory failure with various severity. Complications and deterioration in the cardiovascular system were not observed during the follow-up period, which varied from 3 to 48 months.

CONCLUSION: Our results show the efficacy of using helical Tomotherapy considering positive outcomes, being that three out of four patients are in remission with low acute toxicity and late complications. There are a small number of articles describing bilateral breast cancer treatment with helical Tomotherapy. On this occasion, our data could contribute to the studies of tolerant doses for organs at risk and improve the parameters of treatment plans for bilateral breast cancer. Since the small sample of patients with bilateral breast cancer limits the study, a larger cohort of patients is essential to obtain statistically reliable results.