Cox regression showed in Fig. 3 there were significant differences between HRs of DCISM versus DCIS for CSS in subgroups of age (<40 years or ≥40 years), race (white or black), gradeII, grade III and UD, ER (positive or negative), PR (positive or negative), no lymph node, surgery (yes or no) and radiotherapy (yes or no). Here, PGR is linked to ductal breast carcinoma in situ.