Surgical methods currently applied in the local treatment of pre-invasive ductal carcinoma are largely the same as those used in early-stage invasive breast cancer. Both conditions are treated either with tumor excision (combined with radiation therapy) or with mastectomy. Comparable proportions of DCIS and early-stage breast cancer patients receive the most aggressive form of treatment. Nearly 30% of the former undergo mastectomy. A question thus presents itself: is this the way it should be?

The purpose of DCIS treatment is to prevent its progression to invasive disease or detect a hidden invasive compo­nent. However, in and of itself, DCIS is not a terminal condition and does not directly put life at risk. Indeed, it may be a precursor of invasive cancer, but progression is known to occur in as few as 20–30% of untreated patients. At the same time, it is a quite heterogeneous diagnostic category. Some ductal carcinomas in situ with the lowest degree of malignancy behave more like atypias and show a similar risk of progression, only slightly higher than that for an average 65-year-old woman in the general population. It has even been argued that these DCIS cases are not properly carcinomas at all; labeling them as “cancer” provokes disproportionate fear in patients and compels physicians to take unnecessary and excessive treatment measures. In order to change that, it is first crucial to modify the terminology we use: changes with a very low risk of progression toward invasive carcinoma should be labeled as indolent lesions of epithelial origin (IDLE). To conclude, the local treatment of pre-invasive carcinoma in most cases should differ from that of early-stage invasive cancer. Aggressive methods should be avoided unless specifically required.