Welcome to the Breast Cancer group, @rarelybees2889. The information about LCIS can be confusing. You are in good hands at Mayo to get any questions answered that you may have. I'd also like to introduce you to other members here who have LCIS, like @elsie37 @cindylb @amy11559 @cancersucks to name a few.

You may also be interested in this informative discussion:
– The math of invasive breast cancer risk for LCIS https://connect.mayoclinic.org/discussion/the-math-of-invasive-breast-cancer-risk-for-lcis/

Rarelybees, while we wait for others to join in, it would be great to learn a bit more about you. When were you diagnosed? What information about LCIS are you finding confusing? What are your next steps regarding observation and/or treatment?

Hello, I have just been diagnosed with LCIS. I am considering taking Tamoxifen but is terrified of the side effects. I read that a low dose tamoxifen of 5mg/day for 3 years is just as effective as 20mg/day in lowering my risk of breast cancer. Does anyone have any experience with low dose tamoxifen?

When I was 49 I had LCIS and was prescribed tamoxifen for 5 years. I did end up having a hysterectomy due to large polyps growing on my uterus after having been on it for four years but I did not really notice any other side effects.

Hi,
I was 1st diagnosed in December 2006 with stage 1 ER/PR positive breast cancer (RIGHT side girl) and opted for a lumpectomy, chemotherapy, and radiation. In hindsight, I should have had the double mastectomy then when I was younger (50) and stronger. For 10 years I took Arimidex and every 6 months, I had 3-hour diagnostic mammo's which include all the waiting time.

After 10 years I no longer had an Oncologist he had retired. So, for 2 blissful years, I only had screening mammos until the radiologist recommended a biopsy on the LEFT girl. My thoughts were Pooh Bear here I go again. The diagnosis was LCIS with not enough tissue collected to determine if it was a recurrence of breast cancer. The surgeon wanted to do a lumpectomy and I said No. This was during the high point of Covid and I had not been vaccinated. After 15 months and 2 different radiologists' opinions, I had breast cancer again in the RIGHT girl. No one ever mentioned the LCIS again. If I were in your shoes I would do whatever the radiologist and surgeon suggest. Continue to watch the LCIS with mammos I was told stage 1 breast cancer was easily recognized by radiologists. You will be in my prayers!

Thanks for the response. Can I ask what dose of Tamoxifen you took? The side effect of possible uterine cancer is scaring me to the point of considering a double mastectomy at this point. Am I being too excessively aggressive in my thought process?

I took 10 mg for 5 years. My best advice to you is to find an oncologist that will answer all of your questions. Ask for medical research which has been done on LCIS. There doesn’t seem to be much. What ever you decide to do keep following up with your Doctors. If you decide to have a double mastectomy know that there are side effects from that also. Ask questions about that so you can make the best decision for YOU. You know yourself best. Take care. I truly wish you the best. Smile and enjoy today.

"Am I being too excessively aggressive in my thought process?" you ask.

One way to tell is to give yourself several months to a year to research and consider your alternatives. Your thought process may evolve. Don't do anything non-reversable right away would be my suggestion. You can take this amount of time with LCIS. In fact I had one NP at a breast clinic tell me to wait a year or more for any surgical solutions. If you had invasive cancer, waiting a year would not be an option.

Also if you are post-menopausal, there are other drug options besides Tamoxifen. Not that you would ever want any cancer, but uterine cancer, which is your big concern with Tamoxifen, is more curable than others from what I've read.

I do take an anti-estrogen (Raloxifene because I am post-menopausal.) for my atypia issues that include LCIS but actually most women do not take drugs for LCIS. You can check out the stats but I've generally seen under 30%. The oncologists generally encourage you to take one of the various drugs, but it is not the most common route. You can go with increased screening like annual MRIs plus mammograms instead. I actually do both the drugs and increased screening.

Good luck to you.