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Which is better! Letrozole or Tamoxifen?


I had ILC before surgery and chemo. Now I’m technically cancer free. No lymph nodes.

Please tell me which is best letrozole or tamoxifen? My dr put me on tamoxifen but i read that Letrozole is better for ILC. I am so scared it will recur. I asked my dr and he seemed to think tamoxifen was best.


  • Member Posts: 1,435
    edited December 2021

    Not a subject I know much about, but I found this study, which is referenced in pretty much all the more recent articles about ILC and endocrine therapy:

    Relative Effectiveness of Letrozole Compared With Tamoxifen for Patients With Lobular Carcinoma in the BIG 1-98 Trial

    Results: The median follow-up time was 8.1 years. In multivariable models for disease-free survival (DFS), significant interactions between treatment and histology (ILC or IDC; P = .006) and treatment and subgroup (LB like or LA like; P = .01) were observed. In the ILC subset, there was a 66% reduction in the hazard of a DFS event with letrozole for LB (hazard ratio [HR], 0.34; 95% CI, 0.21 to 0.55) and a 50% reduction for LA subtypes (HR, 0.50; 95% CI, 0.32 to 0.78). In the IDC subset, there was a significant 35% reduction in the hazard of a DFS event with letrozole for the LB subtype (HR, 0.65; 95% CI, 0.53 to 0.79), but no difference between treatments was noted for IDC and the LA subtype (HR, 0.95; 95% CI, 0.76 to 1.20).

    Note that it does say that the end that "subsequent validation in larger data sets is necessary before implementing a routine clinical recommendation of AI for patients diagnosed with ILC"

    I would suggest that you take this study to your MO and ask again why he recommends Tamoxifen for you. And hopefully someone with ILC comes by and can offer more insight.

  • momof2winsplus
    momof2winsplus Member Posts: 18
    edited December 2021

    It depends on your menopausal status. The BIG1-98 study was only on postmenopausal women. Tamoxifen is still the standard of care for premenopausal.

    I had ILC at 43 years old. I was put on tamoxifen. It was so easy, I had no hot flashes or other problems…or so I thought. I had ovaries removed last month because of NAFLD making it dangerous to continue on T. I just switched to letrozole. I am having a few hot flashes, but I’m doing well.

    Discuss with your doctor, but tamoxifen still works well.

    Good luck!

  • margun
    margun Member Posts: 385
    edited January 2022

    am on letrozole for 2 years and I was diagnosed recently with osteoporosis despite taking calcium and vitamin D. By my doctor advise I am taking bisphosphonate now. But in sève emails here I see that there is a lot of reticence taking this med. I am too tired of taking meds, chimiothérapie already made me feel older, but besides that there is a specific concern related to bisphosphonates. It there any other choice given that all anti hormones have se?

    My hope is that if by my next bone density measurement, in a year, all be better and I can stop it. But it is just a hope and I like to here from you your suggestions. I try exercise everyday (moderate such as walking stretching).

  • ShetlandPony
    ShetlandPony Member Posts: 3,063
    edited January 2022

    There is enough concern about ILC and hormonal therapies (ok really about tamoxifen) that there is a trial comparing tamoxifen, aromatase inhibitor, and faslodex in ILC:

    A Trial of Endocrine Response in Women with Invasive Lobular Breast Cancer (TBCRC037)

    Doctors don't change the way things are done until tthere is very strong evidence from clinical trials that eventually alters the standard of care. This is scientific. In my opinion, if there is a lot of data questioning the effectiveness of tamoxifen for ILC, I as an individual patient can't afford to wait around for that if there is an acceptable alternative. (Or rather I shouldn't have.)

    In your case, LOJ, you could argue that your stage IIIB is enough to justify a stronger treatment that could include ovarian suppression or removal and an aromatase inhibitor.