[Radiotherapy in breast-conserving treatment for ductal carcinoma in situ: first results of the EORTC randomised phase III trial 10853].

t BackgroundBackground Ductal carcinoma in situ (DCIS) of the breast is a disorder that has become moree common since it may manifest as microcalcifications that can be detected by screeningg mammography. Since selected women with invasive cancer can be treated safelyy with breast-conservation therapy it is paradoxical that total mastectomy has remainedd the standard treatment for DCIS. We did a randomised phase III clinical trial too investigate the role of radiotherapy after complete local excision of DCIS. MethodsMethods Between 1986 and 1996, women with clinically or mammographically detectedd DCIS measuring less than or equal to 5 cm were treated by complete local excisionn of the lesion and then randomly assigned to either no further treatment (N=503)) or to radiotherapy (N=507. 50 Gy in five weeks to the whole breast). The mediann duration of follow-up was 4.25 years (maximum 12.0). All analyses were by intentionn to treat. ResultsResults 502 patients were followed up in the no further treatment group and 502 in the radiotherapyy group. In the no further treatment group 83 women had local recurrences (444 recurrences of DCIS. and 40 invasive breast cancer). In the radiotherapy group 53 womenn had local recurrences (29 recurrences of DCIS, and 24 invasive breast cancer). Thee 4-year local relapse-free rate was 84/r in the group treated with local excision alone comparedd with 919f in the women treated by local excision plus radiotherapy (logrank P=0.005.. Hazard Ratio=0.62). Similar reductions in the risk of invasive (40%. P=0.04) andd non-invasive (35%. P=0.06) local recurrence were seen. ConclusionsConclusions Radiotherapy after local excision for DCIS. as compared to local excision alone,, reduced the overall number of both invasive and non-invasive recurrences in the ipsilaterall breast at a median follow-up of 4.25 years. RadiotherapyRadiotherapy in breast-conserving treatment for DCIS 33 33