Adjuvant radiotherapy in breast cancer--the treatment of lymph node areas.

Adjuvant radiotherapy decreases the risk of locoregional recurrences threefold, according to the results of many randomized trials and overviews. In patients treated with total mastectomy, the risk of local recurrence is mainly related to the number of involved axillary nodes, i.e. about 25%, 35% and 55% at 10 years when 1-3, 4-9 and 10 or more nodes are involved, respectively. In contrast, at 10 years, less than 15% of patients with negative axillary nodes relapse locally. The effect of adjuvant radiotherapy on distant metastases and overall survival is a controversial issue. On the one hand, recent results are compatible with the existence of a mechanism of secondary dissemination generated from locoregional tumor nests. The beneficial effect of radiotherapy can be observed whether with or without adjuvant systemic treatment. On the other hand, a deleterious late toxic effect, mainly cardiac, has also been shown. The importance of improvements in radiation techniques and quality assurance to obtain a positive balance in terms of overall survival is emphasized.