High ER (especially) suggests that the breast cancer cells are estrogen receptors. Therefore, limiting estrogen is a treatment for ER positive BC. Having a treatment is generally regarded as “ a good thing” as it may prevent recurrence.

Pre menopausal women still produce estrogen in ovaries ( which then needs to be shut down). Post menopausal women may have estrogen stored in adipose tissue “belly fat” as well as the ability to continue to produce estradiol (in adrenal glands) which converts to estrogen with the help of aromatase . Aromatase Inhibitors work to prevent the conversion thus cutting down availability to BC cells, which require it, to proliferate.

So if you are ER PR positive there is THIS ongoing potential treatment available. As AI’s lower circulating estrogen, side effects, related to this deficit, are felt. Most women find the side effects to be tolerable or can be mitigated. Some women find them to be intolerable. Oncologists may try taking a several week “vacation” then returning to the med or switching to another of the 3 to find a more comfortable match. This sometimes helps.

As it is a daily medication it can be stopped at any time if need be.

@joannemm34293 a high ER (and PR) means that aromatase inhibitors (or tamoxifen for pre-menopause) should have a high level of effectiveness. The scores make the cancer more treatable, in other words.

I asked the Breast Cancer Index people why extended treatment had no benefit for me, with those high ER and PR scores and a low Oncotype. They explained that the Oncotype looked at how many cars were in the road and they looked at the speed of the cars (or vice versa, I cannot remember).

I would think the BCI result would show that my cars were moving slowly but then I had a high risk of recurrence of 5.7% (they have since changed their labelling of risk).

It's hard to base our decisions on Oncotype, BCI and other testing but we don't have much choice. My bones needed attention or I might have continued another two years anyway. One oncologist said I could two more years anytime so once my bones are taken care of (almost done Tymlos) I might go back and ask about that. Letrozole would not be to treat but to prevent.