Jacky Luiten

132 | Chapter 9 of patients with favorable features for whom the risk of invasive recurrence in the absence of radiotherapy is ultimately low that radiotherapy can safely be omitted. 48 Our invasive relapse ‐ free survival analysis, shows a very low probability of local recurrence in recent years, suggesting that a good selection of patients who do not require radiotherapy has proven to be possible. However, the majority of patients in whom BCS is performed for DCIS is still receiving radiotherapy, which may possibly be unnecessary in selected cases. Therefore, radiotherapy should be tailored to patient factors, tumor biology and validated prognostic scores on risk of local recurrence. 49,50 More research is needed to determine whether the use of radiotherapy can be safely limited further. Our study also showed a de ‐ escalation in axillary treatment, with a replacement of axillary lymph node dissection by sentinel lymph node biopsy (SLNB) and an observed decline in SLNB in more recent years. This shift is probably related to the reporting of rather low risk of sentinel lymph node involvement, ranging from 0 to 10%. 51 ‐ 53 Even if the SLN is found positive in patients with a preoperative diagnosis of DCIS, it is most frequently reported to present as micrometastases (defined as small metastases sized 0.2–2.0 mm), which are of limited clinical value in this respect. 54,55 Nowadays, a delayed SLNB following lumpectomy if invasive cancer is shown, is considered a feasible option. Therefore, we agree with a recent study by Van Roozendaal et al. who suggest omitting SLNB completely in patients with DCIS undergoing BCS. 53 In patients undergoing mastectomy SLNB cannot be performed afterwards. Clinical evidence to forego SLNB in these patients is scarce or lacking, therefore SLNB may still need to be performed in DCIS patients with risk factors for invasive disease undergoing a mastectomy. In conclusion, the use of BCS, radiotherapy and axillary staging in patients with DCIS varies over time. The lack of consensus in recent literature reflects our limited knowledge about the natural course of untreated DCIS. In the interest of shared decision ‐ making patients should be informed about these dilemmas, since current treatment protocols may result in overtreatment of many women.