Not everyone with ductal carcinoma in situ of the breast treated with breast preservation needs post-excisional radiation therapy

While the results of NSABP protocol B-17 and EORTC protocol 10853 prove tha t radiation therapy decreases the overall rate of local recurrence in patie nts with DCIS, there are clearly subgroups of patients who do not benefit f rom radiation therapy or whose benefit is so small that the addition of rad iation therapy to their treatment regimen is simply not worthwhile. Identif ying these subgroups is of paramount importance. Factors like tumour size, margin width, nuclear grade, and the presence or absence of comedonecrosis can be used to define favorable subgroups that do not require post-excision al radiation therapy. The most recent results: of NSABP protocol B-17 and EORTC protocol 10853 co nfirm that, regardless of treatment, there is no difference in the single m ost important end-point: survival. If there is no difference in breast canc er mortality, it is clearly worthwhile to try to define the subgroups of pa tients who can be spared the time, costs, and side-effects of a treatment t hat they do not need. (C) 2000 Harcourt Publishers Ltd.