No Tamoxifen after UMX?

Hello! I am in a similar situation to you ladies. I had a unilateral mastectomy in January also (extensive area of DCIS). However, my doctor did recommend Tamoxifen because I'm ER+. He "recommended it" but at the same time, he said he wouldn't call me crazy if I decided NOT to take it. Its all odds. Maybe it will lower the odds of another breast cancer.... but I have a family history of endometrial cancer (a possible side effect of Tamoxifen) and I have fibroids also.... and I've heard Tamoxifen can cause them to grow very large.

Also, I am perimenopausal and I've heard the more common side effects of Tamoxifen (mood swings, hot flashes etc) can be more pronounced in perimenopausal women. That's a little scary, because my mood is already "swinging!" lol! I am more comfortable monitoring the other breast w/ mamograms. The breast that was removed has always had more issues..... more benign issues, more cysts, etc which made my mamos more difficult to read, but still they managed to catch me at stage 0. I feel if something starts happening in the other breast, it would be even easier to spot.

I had multi-focal DCIS, so ended up with UMX. I did speak to an MO about Tamoxifen, but as I was ER-, he said there was "no evidence" that it would provide any benefit for me. But he was STILL willing to prescribe it for me, if it would give me peace of mind. I decided that if it wasn't really going to help me, I didn't want to sign up for the side effects (I was 38). So after my reconstruction surgeries, I was finished. I have been NED for 14 years.

ChiSandy, when Tamox is prescribed after a UMX for DCIS, it isn't being prescribed to prevent a recurrence of the DCIS - that risk is usually low enough after the MX that Tamoxifen isn't warranted (the risks from the drug being greater than any benefit it might provide). The reason Tamox might be prescribed to someone who's had a UMX for DCIS is for protection of the remaining 'healthy' breast - the same way that Tamox might be prescribed to someone who is high risk because of family history or ADH or something like that. Even if the original DCIS diagnosis was ER-, a new primary in the contralateral breast could be ER+ (since about 80% of breast cancers are) so Tamox could reduce that risk. That's why it might be prescribed.

That said, it's important to consider that the new primary risk that we face is spread over the rest of our lives. Most of us will never be diagnosed with BC again, but some of us will be - and that could be in 3 years, or 10 years or 25 years or 40 years. My MO estimated my risk to be diagnosed with BC again during my lifetime to be about 22% (double the risk of the average 49 year old, which is the age I was when diagnosed). However because that risk is spread over 40 years (to age 90), it's actually only about 0.5% per year. Since 5 years (or these days, 10 years) of Tamoxifen isn't going to provide protection for the whole 40 years, the risk vs. benefit assessment needs to consider one's risk level only for the years during which Tamoxifen will be taken (plus 2 - 3 extra years, since Tamoxifen's effect lingers). As I mentioned in my earlier post, my 7 - 8 year risk (assuming 5 years of Tamox) was only 4%, meaning that the risk reduction benefit I'd have received from Tamoxifen would have been a bit less than 2% (Tamox provides approx. a 45% risk reduction benefit during the years you take it, and a reduced benefit for the next 2 to 3 years).

So whether one has an ER+ or ER- diagnosis of DCIS, after a UMX Tamox can be considered as protection for the remaining breast, but the rationale to take it is not particularly compelling for many of us (other than for peace of mind), unless we are very high risk over the years in which the Tamoxifen will be taken. That's why many MOs don't recommend Tamox after a UMX for DCIS (whether the DCIS was ER+ or ER-) and why it's considered optional even by most MOs who do prescribe it.

Annette, you're right that dividing one's risk equally per year over the remaining years of one's lifetime is not correct because we don't in reality have the same risk at every age. I figured my explanation was complicated enough without getting into that finer level of detail. But in fact, to your point, as women our highest risk years are actually in our 60s and 70s. I was diagnosed at 49, at a time when Tamoxifen was only given for 5 years. So if I'd taken Tamoxifen then, I would have protected myself for the next 7 or 8 years while I was in my 50s, which is a lower risk period. And in reality since my average annual risk over 40 years was estimated to be about 0.5%, my annual risk over those years in my 50s would actually have been even lower than that. It was another reason I didn't take Tamoxifen. Now that I'm 60 and coming into my higher risk years, it may actually make more sense for me to consider Tamoxifen now than it did at the time of my diagnosis. My annual risk over the next 10 - 15 years is probably closer to 0.7% - 0.8% per year (again, this is an average for that entire time period). Doing some basic math, if 10 years of Tamox would get me about 13 years of risk reduction, my risk to be diagnosed with a new primary over the next 13 years is probably about 10% which means my risk reduction benefit from Tamox (45% benefit) would be 4.5%. That's more compelling but for me not really compelling enough to get me to take Tamox for 10 years. But for someone else, I can appreciate that this level of benefit might warrant going on Tamoxifen (or an AI).

Annette, I'm sure I could get a prescription for Tamoxifen if I wanted one, but as I said, even a 4.5% risk reduction benefit isn't compelling enough for me to want to take Tamox for 10 years. As much as I wish to avoid another BC diagnosis, breast cancer is not what scares me most. What scares me more is DVT/PE, so increasing this risk, even by a tiny amount, is a huge 'con' that for me wipes out even a more significant BC risk reduction benefit.

What's important I think is that everyone understand their breast cancer recurrence risk and new primary risk, and the amount of risk reduction benefit they will get from Tamoxifen, based on their owndiagnosis, prognosis and age. Then that should be weighed against the risks from Tamoxifen, which again should be personalized to reflect age and other personal and family health issues. Looking at those two things together, we each can make out own decision about whether or not Tamoxifen is right for us.

I also had a unilateral mastectomy for extensive DCIS in late January. I am postmenopausal and although I have a maternal aunt who had breast cancer, my genetic testing all came back negative. I met with the oncologist last week and he did not recommend tamoxifen. He explained that the risks outweigh the benefits in my case. He did recommend that I exercise five times a week and suggested a Mediterranean diet. I hope with that and some careful monitoring I will be okay. It is a little nerve wracking to be done with treatment, but mostly I just feel relieved!