Phantana-angkool A, Voci AE, Warren YE, et al. - Researchers sought to determine the role of sentinel lymph node biopsy (SLNB) when ductal carcinoma in situ with microinvasion (DCISM) is identified on core biopsy via investigating the upstage rate to invasive cancer and axillary lymph node metastasis in patients diagnosed with DCISM, and examining if predictive variables could be identified that may assist in assessing the cases who may most likely benefit from a surgical axillary evaluation. Seventy patients diagnosed with DCISM on core biopsy were retrospectively reviewed. On final surgical pathology, a final diagnosis of DCISM or T1mi cancer was made in 49 patients (70%), whereas upstaging of 21 patients (30%) to measurable invasive cancer (> 1 mm) was done. Sentinel lymph node metastases was evident in one of 49 patients (2%) with DCISM on final pathology and 4 of 21 patients (19%) with measurable invasive cancer. This suggests that despite the upstage rate to measurable invasive cancer was 30% in this cohort of patients with DCISM on core biopsy, there remained low findings of a positive SLNB at 7%. They identified no predictive variables to inform if the routine practice of SLNB may be omitted in some patients with DCISM.