Rationale and hypotheses underlying this trial
tumor
DCIS, TUMOR
Although the results obtained from cohort 1 of the ECOG E5194 trial and the no RT group of the RTOG 9804 trial showed a 7-year IBTR rate ranging from 5.6%–10.5 [For patients with breast DCIS aged > 40 years and with pathological tumor features meeting the ECOG E5194 cohort 1 criteria and positive ER, we hypothesized that the administration of low-dose tamoxifen is not inferior to the prescription of RT in terms of reducing the IBTR.