Finished 5 years of tamoxifen should I go 10?

What was your Oncotype score, and what's your diagnosis and your risk?

For me, if I'd been able to tolerate the Tamoxifen with few problems, that would be the deciding factor. My decision would be very different depending on the diagnosis/prognosis/risk level.

Here is part of Special K's post on the Breast Cancer Index test that you might find helpful:May 26, 2020 01:05PM SpecialK wrote:

I was Her2+ and did the Breast Cancer Index test at the five year point. BCI gives two results, a figure that predicts recurrence risk, and one that gives an estimate of benefit from continuing anti-hormonal drugs. There are multiple arrangements - high risk of recurrence and high benefit of continuing the drug, low risk of recurrence and low benefit, low risk of recurrence and high benefit, and the dreaded high risk of recurrence with low benefit. Although you are not HER2+, I think this describes the test.

I was 39 at diagnosis. I couldn't tolerate tamoxifen but am tolerating toremifene. Honestly if I were in your shoes, I think I'd keep going past *10* years, and barring unexpected new developments, my current plan is to stay on toremifene as long as I can tolerate it.

My understanding is that they don't have evidence about the benefit after 10 years, which is different from having evidence that it does not continue to benefit. Especially for a woman who hopes to live 40+ years after diagnosis. I think we just don't have enough longitudinal data yet, and so many women stop hormone therapy the instant they can because of side effects.

I am not a scientist and would love to be corrected, but I haven't seen anything that indicates to me that there is something like a lifetime dose of tamoxifen that you build up to and it sticks around. Hormone positive cancer can and does recur 15, 20+ years after initial diagnosis, so it seems to me like whatever cancer cells escaped the body are capable of surviving a longer course of tamoxifen, and we don't have evidence to the contrary.

That said, if you are having side effects that impact your quality of life, it is a whole other equation, and not simple at all.