Locoregional radiation therapy as a stage of complex stage for de novo metastatic breast cancer

Background. At the moment, in order to increase both local control and relapse-free and overall survival in patients with de novo metastatic breast cancer, in addition to systemic therapy, local methods of therapy are also used, such as radiation therapy to the primary tumor. Radiation therapy can be performed both in the adjuvant and radical regimen. The data about the comparability of effectiveness of radiation and surgical methods of treatment in terms of overall survival are currently contradictory.

Aim. To compare rates of progression-free survival and the frequency of achieving local control of the primary tumor among patients with de novo metastatic breast cancer after a radical course of radiotherapy or surgery followed by adjuvant radiation therapy as part of combined treatment.

Materials and methods. The study cohort comprised 89 patients, from which in 50 (56 %) patients radiation therapy was performed as an adjuvant treatment after surgery on the primary site, and in 39 (44 %) patients, it was performed as a radical treatment. The irradiated volume included the ipsilateral half of the anterior chest wall or the breast, depending on the extent of surgery, and the regional lymphatic drainage zones, if it was clinically indicated, in the first group, and the breast and regional lymph nodes in the second group.

Results. Two-year progression-free survival was 74 % in the adjuvant radiotherapy group and 67 % in the radical radiotherapy group, two-year local control was 100 % and 82 %, respectively. In both subgroups, progression was most frequently detected in patients with luminal B HER2-negative subtype.

Conclusion. Both presented options of radiotherapy showed their effectiveness in terms of achieving local control and progression-free survival. Further research is needed on the role of radiation therapy in the combined treatment of patients with de novo metastatic breast cancer, including search of subgroups of patients for whom radiotherapy in one regimen or another will lead to further improvement in both progression-free survival and overall survival.