Radiotherapy in DCIS, an underestimated benefit?

Often considered an "indolent" disease for which a treatment de-escalation is advocated, ductal carcinoma in situ (DCIS) of the breast has been recently shown to be associated with a significant increase in long-term mortality in case of invasive local recurrence (LR). The publication of data from four randomised trials did not prevent the continuation of the debates about the pros and cons of postoperative radiation therapy (PORT) for optimal DCIS management. Actually only partial answers regarding the impact of PORT on local control had been brought by these randomised trials among others due to differences in pathological assessment among these controlled studies. A biologically heterogeneous disease, DCIS is characterised by a large variation in clinical behaviour, which hampers the identification of those patients for whom PORT might be considered as an overtreatment. At the light of the most recent biological and clinical studies, this review tries to identify accurately the LR risks associated with both tumour- and patient-related factors and to analyse the treatment-related parameters impacting significantly on the patient outcome.