Aromatase Inhibitor

I contemplated it but I have been on letrozole since April, 2025. My oncologist really prefers this drug for ILC so I have been working through joint pain. The more I move the better I am. I do stretching and breathing and light yoga every day and I lift weights three times a week and walk and ride my indoor bike sometimes outdoors. I have had more issues with being so tired from not having estrogen. I know other women have switched drugs and have had similar issues since they all deplete estrogen. I think it is worth a try but personally motion is lotion for me and movement seems to help the joint pain. Best of luck to you.

I did. First, was on Anastrozole for about 4 months, switched to Letrozole due to severe daily headaches.
Letrozole was no improvement for me but hung in there for about 5 months. Finally since March I am on exemestane. The headaches have subsided a great deal. I still get them but can cope. As far as joint pain, I have had it with all 3 AIs but I am tolerating this pain which is not constant. No walk in the park but it's doable.
The headaches were really incapacitating for me. Thinning of my hair is another issue but I use hair products to volumize my hair so it doesn't look bad once it is all styled. Also, since starting the AIs last year I gained 10 pounds which are almost impossible to lose. I was told the AIs slow your metabolism and that's the culprit. I cut back on food portions and trying to exercise on my treadmill and do weights for osteoporosis. My DEXA scan September 2025 showed osteopenia in my left hip for the first time.
I have read here that "everyone" responds differently to each AI. So I would suggest to give it a try.
Hopefully it will be the AI that you can stick with.
All the best to you!

I've been on Letrozole since Jan 2026 for ILC and have many of the same symptoms. My joint pain since to "float around"--that is, for awhile it's my knees, then my ankles, then another day it's foot pain. Lots of trigger finger. It seems to particularly attack areas of past injuries, like a broken ankle, or bones in my feet, but sometimes new places that have never bothered me before (knees). Like others, the more I move, the better it is. I'm finding it helpful to keep searching for the right exercise or movement for each pain. For knees, I was surprised how much it seemed to be the leg press machine at the gym that seems to help. Walking is very helpful, but it does feel at times like my legs have turned to lead. I've been fortunate to avoid the headaches. I've had extreme dry skin, even eyes and nasal passages, and am constantly having to moisturize something. I have significant osteoporosis, was pushing for Tamoxifen, but my endocrinologist pushed for me to "let my bones take the hit" for what he sees the survival advantage of an AI and "we'll deal with the bones later." I'm not sure how much "later" I have; I'm 73, and am also a 6 year ovarian cancer survivor. I'm trying to be very diligent about weight lifting twice a week, and then using Dr. Lisa Moore's Brick House Bones 52 week osteoporosis series (free on youtube) for posture, strength, impact and balance the rest of the week. I have a digital scale with a bunch of measures (fat, lean body percentage, bone mass, muscle mass) and I watch it carefully to make sure that I'm maintaining my proteing levels, and any weight loss (from a high protein, cholesterol lowering, weight loss diet created for me by my "dietiticain" (aka AI (artificial intelligence type)). I watch the trends, not any absolute numbers. I should have an idea of how much my bones are being affected after December's Dexa scan. I'm also feeling that a different AI would probably have similar effects, so I'm staying with Letrozole for now. I had no idea how much the cost of staying alive still would involve so much maintenance, and I miss my hair being thick! I just really wish there was more research done specifically on ILC; I don't think the Predict tool used is really reliable for ILC because the data is primarily on ductal cancer, not ILC. It would be easier to deal with all these side effects if there was more evidence that it's actually helpful for preventing ILC recurrence.

I started with Anastrazole. While not incapacitated, I did experience quite a bit of bone and joint pain. Just general every day but also the moving areas of acute pain like being stabbed. Today the left ankle, tomorrow right hip etc. After 9 months tried exemestane. Not really pain, a little achy but easily walk it out. My problem ther started at month 3 - weight gain (10# in 1 week!), then extreme fatigue, pain and joint swelling in hands but not quite to the trigger finger, weakness then insomnia - barely getting 3 hours of sleep a day. Accompanying that, increase in bp and heart rate - couldn’t even do a mile without hr up into the 170s. 1 month vacay (I actually took 6 weeks) and 80% better. He wanted me to try it again at same dose - won’t do every other day because it’s not standard of care. Everything restarted within 2 weeks. So took another 2 weeks off and I’ve now been on Letrozole for 1 week today. Kind of scared because I’ve read that Letrozole is like Anastrazole on steroids but will give it a go. If this doesn’t work, we try tamoxifen. So yes, it’s worth trying something else and exemestane works differently so you may do well with it.

I am 68 years old and was diagnosed with Pleomorphic ILC in January of 25. I had a lumpectomy, with clear lymph nodes, and 5 rounds of radiation.
I was allergic to both Anastrozole and Exemestane. I tolerated Tamoxifen (20mg) for 9 months before developing eyelid swelling, facial swelling, hives on my neck, and inner thighs.
I have since read that Tamoxifen is not recommended for ILC.
I have an MRI at the end of July and will see my oncologist early August. I assume they will reduce my Tamoxifen to 10 mg to see if I can tolerate it.
I am new to the site and wanted to see if anyone else had PILC.

@wews i’ve been on Letrozole for seven months the last of the three AIs started January 23, 2023 I do PT and Chiropractic and manipulation three times a week. I walk between 10 and 15,000 steps a day and that includes weights. I belong to a JIM and I try to walk through everything fuss at the same time, my parents are in there 80s going on 90 and I helped out with them the same time.

@loridalton I was also diagnosed with PILC in June 2024. Had a single mastectomy (3 nodes with carcinoma), chemo, excision surgery to clear margins and radiation. I tried Letrozole for 2 months with carpal tunnel, insomnia and bone pain, tried Exemestane for 1 month with GI issues and have now been on Anastrozole for 9 months. I'm 67, have 3 trigger fingers, insomnia and recently depression, so I took a drug holiday for 2 weeks and feel GREAT. Totally back to myself again.
I don't want to start another AI, so I'll go back on Anastrozole at some point and do my best.

@mistymar
Thanks for the advice and in particular thanks for sharing your experience. with degree and quality of pain. I was struck when you wrote "Just general every day [bone and joint pain] but also the moving areas of acute pain like being stabbed." The extent of the acute pain I have experienced on AI (letrazole to date) has been striking and your description reminded me of my own experience. The pain is not in any ways similar to the sensation of MSK pain I have experienced in the past pre letrazole. When I move some areas it feels like what I can only describe as biting pain- not aching, not sore, not strained or overused. In fact certain movements amke me cry out in pain. I have been off letrazole since the end of May ( three months on it) . since then had 16 sessions radiation. Had to take naproxen/ppi vimovo to be able to hold arms in proper position for radiation . Of course raised blood BP as did letrazole. Sleep disturbance acute as well. I am now planning on exploring the role of pre-existing fibromyalgia in CONJUNCTION with breast cancer treatment as an explanation for the persistent acute long term and QOL threatening symptoms. Previous Fibro was not particularly disrupting.

Hi, I made the switch to Exemestane because of joint and back pain, after being on Letrozole for over a year. I was hesitant to make the change, fearing the outcome could be worse, but it ended up just fine. I do still have a little joint and back pain, but it’s tolerable, and as many have stated, getting up and moving works wonders! Good luck with your decision!

I took Letrozole for over 5 years for ER and PR +. I also took Zyrtec to help with the pain. In 2025 I was diagnosed with TNBC . I had a mastectomy followed by chemo. It was suggested that I take Claritin for bone pain. It seemed to help. It might also help with AI side effects. Maybe check with your medical team to see if Claritin would help with side effects.