The international radiotherapy (RT) expert panel has revised and updated the RT guidelines
that were accepted in 2020 at the 4th Hungarian Breast Cancer Consensus Conference,
based on new scientific evidence. Radiotherapy after breast-conserving surgery (BCS)
is indicated in ductal carcinoma in situ (stage 0), as RT decreases the risk of local
recurrence (LR) by 50-60%. In early stage (stage I-II) invasive breast cancer RT remains
a standard treatment following BCS. However, in elderly (≥70 years) patients with
stage I, hormone receptor-positive tumour, hormonal therapy without RT can be considered.
Hypofractionated whole breast irradiation (WBI) and for selected cases accelerated
partial breast irradiation are validated treatment alternatives to conventional WBI
administered for 5 weeks. Following mastectomy, RT significantly decreases the risk
of LR and improves overall survival of patients who have 1 to 3 or ≥4 positive axillary
lymph nodes. In selected cases of patients with 1 to 2 positive sentinel lymph nodes
axillary dissection can be substituted with axillary RT. After neoadjuvant systemic
treatment (NST) followed by BCS, WBI is mandatory, while after NST followed by mastectomy,
locoregional RT should be given in cases of initial stage III-IV and ypN1 axillary
status.
