5mg vs 10mg of Tamoxifen

Welcome, @gcroemer,
@vivi1 posed a similar question in this helpful discussion:
- Taking a Lower Dose of Tamoxifen? https://connect.mayoclinic.org/discussion/taking-a-lower-dose-of-tamoxifen/

Also see this related discussion:
- Weight gain from Tamoxifen? https://connect.mayoclinic.org/discussion/weight-gain-from-tamoxifen/

Gcroemer, I'll be interested what your oncologist suggests too.

I, too, had invasive ductal carcinoma, stage 1. I started with 5 mg., then 10, then 10.5. At 10.5 I started bleeding. Imagine having post menopause bleeding, coupled with hot flashes! I went down to 10mg. and dealt with leg pain and swelling, hair thinning and loss, hot flashes, mood swings, and brain fog. I went down to 5mg. and it is so much better. But, I didn't stop there. I take indole-3-carbinol. 200mg. It is being investigated as a more natural way to deal with ER PR positive breast cancer. It acts as an aromatase inhibitor. The trial is using 150mg. X 2. It is the only way I can try to do something, and not give up completely. I won't live with the quality of my life being so ruined by the utter crap the oncologist offer.

Yes, I tried low dose tamoxifen based on the research of oncologist Andrea De Sensi, which is available online . I was diagnosed with Stage 1A IDC, and had a lumpectomy followed by radiation. As well, I am very active and fit at a 19-20 BMI, have changed my diet to mostly vegetarian, and think one size dose fits them all illogical. My oncologist went along with 10mg tablets to start, wanting me to increase to the standard of 20mg. 10mg seemed too much, so I first tried splitting the pills, but they are not scored and splitting is not advisable, so I took them every other day. Even at 5mg you get side effects, and in my case they included abdominal bloating, leg cramps, moodiness, and finally calf pain that may be associated with deep vein thrombosis. So while tamoxifen may be easier on the bones and heart, it was problematic for me with the endometrium and DVT. I am doing better on anastrozole, again taken every other day, which my oncologist would rather I up to the standard daily dosage but accepts my lower dose as better than not taking any anti-estrogen drug at all. IMHO, given medical advice, we have to finally decide what works best for our health concerns and quality of life.

I just went off Anastrozole and about to try 20mg Tamoxifen. I am 75, early stage. Now reading about weight gain and other side effects from Tamoxifen. At my age I don't want to be in misery! The first oncologist I saw explained that my risk of reoccurrence is 15% AI reduces that by one half. I'll try tamoxifen for 90 days but am seriously considering going off all AI's.

Thank you so much for your replies. I feel seen and understood! My doctor said something is better than nothing so I'm going to try the 5mg. Apparenly this dosage isn't available in pill form here in the US, but is in Europe?? Has anyone else heard that? I'll try to use a pill-splitter to cut the 10's.
I agree that a one-size-fits-all approach isn't realistic. Am hoping more research comes out about a lower dose. There is absolutely no way I could have remained on the 20mg when I could barely walk. I am an active person and exercise is really key to my well-being. I've gained about 10-15lbs since starting tamoxifen....sigh. I will also do some further research on anastrozole and indole-3-carbinol. Thank you friends.

Did your oncologist base the 15% recurrence risk on genomic or other tests of tumor tissue?

I don't know what it's based on.

I had genomic testing that yields a risk of recurrence percentage. If you had the OncotypeDX or other test that does, it's helpful. Or maybe he's relying on the stage, grade and hormone sensitivity noted in the tumor biopsy and citing statistics that apply to it. (My oncologist pretty much guessed what my OncotypeDX score might be so it was extra reassuring when the clinical and genomics perspective matched.)

I am 81. I decided AL's were not for me. My mental misery is just to much on them. If I get cancer again, I'll take Herceptin, being HER2+ , but not Taxol and I'll have radiation.

How are you feeling? I heard the same story from other ladies.