There were no significant differences between the effects of age < 50 and ≥ 50 years [Supplementary Figure S4A: (Fixed-effects model) HR, 2.75; 95% CI, 0.50–15.22; p = 0.25, (Random-effects model) HR, 3.28; 95% CI, 0.10–112.85; p = 0.51] or between the effects of ER-positivity and ER-negativity on DFS in the DCIS-Mi patients [Supplementary Figure S4B: (Fixed-effects model) HR, 0.38; 95% CI, 0.07–1.97; p = 0.25, (Random-effects model) HR, 0.38; 95% CI, 0.07–1.97; p = 0.25]. This evidence concerns the gene ESR1 and ductal breast carcinoma in situ.