Ductal Carcinoma in situ after Core Needle Biopsy: In Which Cases Is a Sentinel Node Biopsy Necessary?

Introduction: In some hospitals it is still common practice to carry out a sentinel node biopsy (SNB) if ductal carcinoma in situ (DCIS) is determined in preoperative staging, although this is against international guidelines. The reason for this is because an infiltrative component can be demonstrated frequently in the final pathohistological examination. In this study, we wanted to investigate possible predictors for infiltrative growth, to select patients to do an SNB or to omit it. Material and Methods: All patients with DCIS in the core needle biopsy (CNB), who were treated with surgery including an SNB, were included in a prospective data registry. Patient characteristics were collected through physical examination, mammography and ultrasonography. All characteristics of the DCIS were noted. After surgery, the pathological results were collected. Results: From the 287 patients, 39 (13.6%) had an infiltrative component in the definitive pathological examination despite only DCIS in preoperative CNB. In total, there were only 14 (4.9%) positive SNBs, of which 11 patients had infiltrative growth in the breast tumor and 3 (1.2% of patients with DCIS alone in the final pathology) did not. In addition, characteristics of the CNB, including microcalcifications and comedonecrosis, did not show a statistically significant higher risk for infiltration. Discussion: Considering the low rates of positive SNBs in our population, we think that an SNB should not be performed in advance when DCIS is diagnosed, because if infiltrative growth is found in the final biopsy, an SNB could always be performed afterwards. Only if an SNB cannot be performed afterwards is an SNB indicated.