Effect modifiers in a randomized phase III trial of low-dose tamoxifen in breast preinvasive disease.

1500 Background: Low-dose tamoxifen (babytam) at 5 mg/day for 3 years decreases local or contralateral recurrence by 52% in women with hormone sensitive breast pre-invasive neoplasia after surgery (DeCensi et al JCO 2019). Here we report the results of exploratory analyses to assess whether the benefit of babytam varies among subgroups of patients defined by individual characteristics. Methods: Post-hoc subgroup analyses were performed according...