The absolute benefit of anti-estrogen therapies in preventing DCIS recurrence is estimated to be around 3-5% over a decade.

“so in B17 they randomized patients to surgery alone for dcis lumpectomy alone versus lumpectomy plus radiation and in that study at 10 years about 25 or 30% of the women who had surgery alone had had a recurrence or second cancer or you know D of dcis or invasive cancer in the breast radiation cut that in half to about 12 to 15%”

“and so the the rules apply so it drops it by half drops it by half but the absolute benefit is a lot smaller because the Baseline risk is no longer way up here it's kind of down here and so for that reason the marginal benefits of the anti-estrogen approaches are something on the order of you know 3 to 5 perc in terms of preventing uh a recurrence”