I've been told by oncologists that the current thinking is that anti-hormone therapy can reduce the risk of loco-regional recurrence by an estimated 42-45%, which usually is called 50% for simplicity, over 5 years. That is a mean ("average") reduction. For someone with a personal high risk of recurrence, a 45% reduction is a big advantage for Team Anti-Hormone Therapy.

For someone with a very low risk, it's not as substantial. [My risk, IF the OncotypeDX test is valid, 'could' be reduced from 5% to 3% if I took the drugs. If anastrozole could reduce risk of recurrence to 0%, I'd have to reconsider not taking it.]

But my risk reduction from 5% to 3%, while a big 40% reduction, is only a small two percentage points.

I've seen doctors confuse percentage with percentage points so just want to clarify this point and restate that the "average" risk of recurrence is currently thought to be ~45% over 5 years for women with breast cancer taking anti-hormone therapy.