Weakly ER+, PR-, Pre-Menopausal... Tamoxifen, AI or neither?

Hi everyone,

I have most of my history in my signature. I had a PCR from chemo, but still did a bilateral mastectomy and radiation due to the aggressiveness of the tumor and because I am BRCA1+. My MO puts my risk of recurrence at less than 10%, but can't be more specific than that. It could be 2%, 9%, 5%, or anywhere in between. All he knows is with my response to chemo, the risk of recurrence is lower than if there were some type of residual cancer burden at the time of surgery. MD Anderson's website gave me an 88% disease free survival for both 5 year and 10 year because of the PCR, regardless of tumor characteristics.

I am still pre-menopausal (cycles returned 2 months post chemo) and my MO is still recommending Tamoxifen, although he expects only a modest benefit for me as I am weakly ER+ (17%). He said that I could have up to a 40% risk reduction from Tamoxifen, but probably not that high because of my low ER+. If my risk were 10%, that would bring my risk down to 6%, but if my risk is 5%, we're only taking about a reduction from 5% to 3%.

He is also recommending I do a monthly Lupron/Eligard shot in addition to the Tamoxifen to suppress my ovaries, as that has shown to be "more effective", although I found conflicting data about that when researching myself. He said I can also do an AI instead of Tamoxifen if I do the ovary suppression, and that has shown to be most effective (up to 50% risk reduction), however he was sticking by Tamoxifen because the difference between the benefit from Tamoxifen and the benefit from an AI is only about 1 - 2%.

I asked about Tamoxifen not being as effective on ER+ PR- tumors as ER+ PR+ tumors and he agreed, but he still feels there is some benefit for me. I also asked about the CYP2D6 enzyme testing to see how well I would metabolize Tamoxifen and he doesn't offer that test. I found a study suggesting data on the CYP2D6 enzyme is flawed anyway.

I can't make up my mind what I want to do. I never want this cancer to come back, but at the same time I don't want to do a hormonal treatment that may not be effective on my type of tumor. I really like my oncologist, but I know he's partly recommending these treatments because he has to. There are scary side effects for both drugs and if I were strongly ER+ and/or didn't do radiation and/or didn't have a PCR I wouldn't be questioning hormonal treatment as much as I am. Part of me is leaning more towards doing an AI over Tamoxifen, as I want to have more children, and the potential uterine changes from the Tamoxifen are more bothersome to me.

My MO called the script in for Tamoxifen and I was supposed to start yesterday, but the pharmacy said it's back ordered so they don't have it yet.

Any insight?