Seeking others who got cancer while taking tamoxifen

I am not in your situation and hopefully others who are respond to your post, but I wanted to comment that I don't think you are a medical anomaly, although you are rare. There is a difference.

For high risk patients, Tamoxifen has been shown in various studies to reduce the risk of a primary breast cancer by anywhere from 40% to about 70%, depending on the study. The average is around 50%, I think. That's a good reduction in risk, but it means that 1/2 of the high risk patients taking Tamoxifen will nevertheless be diagnosed with breast cancer.

The reason you may seen like an anomaly is because the overall numbers are low. "High Risk" is generally considered anyone with 0.5% risk per year or higher. So if you take 1000 women who all have a 0.5% risk per year, over 10 years the breast cancer risk for each woman will be 5%. This means that overall 50 of the 1000 women (5%) would be expected to develop breast cancer during this 10 year period. If this number is reduced by half because all 1000 of the women take Tamoxifen, it means that 25 women will have avoided a breast cancer diagnosis, but 25 women will have been diagnosed, despite taking Tamoxifen. Of course, if over a 10 year period you are looking for 25 women out of 1000, or in aggregate, 2.5% of all high risk patients who take Tamoxifen, any one doctor or hospital might only see one or two patients.

So it is the rare patient who fits this profile, but it's not an anomaly that someone who is high risk taking Tamoxifen would develop breast cancer - because that happens to about 1/2 of the women who take Tamoxifen because they are high risk. That probably doesn't make you feel any better, since you are dealing with a breast cancer diagnosis, but at least you know that you aren't alone in having this happen - even if within this relatively small community, you don't find many others who share your experience.

Hi Tmh0921, I was diagnosed on my right side 2 years after my first diagnosis (er/pr+) while taking Tamoxifen. Thankfully it was caught early (and only by an MRI).I had a lumpectomy, lymph nodes were clear, and 19 radiation treatments. I was then put on Lupron in hopes to get me on an AI. I quit Lupron 3 months later because the side effects were brutal! I’m back on Tamoxifen and better but I’ve noticed an increase in pain and swelling if I eat too many carbs. I tolerated it well when I was initially put on it, but I was also pretty low carb during that time. Basically I’ve had to manage my food to stave off side effects and it seems to work for me. I’ve been genetically tested and came back negative on everything. I do have a family history on both sides.