[ role of radiotherapy in the treatment of ductal carcinoma in situ of the breast]

ABSTRACT

The incidence of ductal carcinoma in situ [DCIS] of the breast discovered during screening mammography is rising. This finding has led to the possibility of further breast conservation. We reviewed in this article the role of radiotherapy in the context of breast conservation. Randomized and non-randomized trials as well as meta-analyses and textbooks dealing with radiotherapy for DCIS have been retrieved from the published literature. Databases for ongoing trials have also been checked. Non randomized studies showed a poor local control with surgery alone, with local recurrences varying between 20 and 40% at 10 years. The use of radiotherapy led to a significant decrease in local relapse thus giving the rationale for phase III trials evaluating the role of radiotherapy. To date there are four trials published dealing with radiotherapy for DCIS EORTC 10853, NSABP B-17, SweDCIS and UKCCCR. All these studies showed a significant decrease in the local relapse to values around 15% at 10 years. This benefit did not however translate into any survival gain. The effect of radiotherapy was seen in all patients sub-groups. However, controversies about the necessity of irradiating all patients and about the dose of the radiation to deliver remain present. Ongoing trials trying to provide answers to these controversies are reviewed. Conservative surgery followed by radiotherapy to the whole breast to a dose of 50 Gy remains the standard for breast DCIS discovered with screening mammography. This treatment should be discussed with all patients until randomized data provide evidence of a low risk category that should not have adjuvant radiation. The use of a boost on the tumor bed remains to be discussed for young patients who have positive margins only until data derived from phase III trials are available