When do I go onto Hormone Therapy Tablets (Not that I want to)

When I started (eight years ago) the standard  period for Letrozole was five years. However during that time, research indicated that ten years demonstrated better results. My oncologist referred to a particular study, with a very large sample, which he was clearly impressed by (and he’s a cautious chap, likes to see research results replicated) and so encouraged me to stay on longer. As side effects seem to have stabilised and I have never had joint pain, I probably will get to ten. Unfortunately there does not seem to be any research that says seven or eight years is better than five - it would be good to know if the benefit is incremental (ie better even if you can’t stick it for the full ten years) or there’s a sudden jump in effectiveness after eight or nine years. Best wishes.