Assessment of the efficiency and safety of additional irradiation of the tumor bed using electrons or high-dose brachytherapy in patients with breast cancer

Aim. To evaluate the efficacy of interstitial high-dose rate brachytherapy (HDRB) or irradiation by electron as the methods for delivering boost to the tumor bed.Materials and methods. We performed a retrospective analysis of 5-year local control after whole breast irradiation and additional boost delivery to the tumor bed by HDRB or by electrons. In 485 breast cancer patients included in the analysis HDRB boost was performed in 247, by electrons – in another 238 women.Results. In 485 evaluated patients, local recurrences were diagnosed in 22 (4.5 %) cases: in 10 (4.0 %) of 247 women after HDRB boost and in 12 (5.0 %) of 238 patients who received a boost by electrons (р = 0.536). We found that age less than 50 years and aggressive subtypes (triple-negative, HER2+, luminal B HER2+) were associated with an increased risk of local recurrence (р = 0.003 and р = 0.004, respectively). The type of boost delivery (HDRB vs. electrons) does not influence the probability of local control in young women (р = 0.547) or in patients with aggressive subtypes of breast cancer. Conclusion. Both techniques of boost delivery (HDRB or electrons) are equally effective in prevention of local recurrence.