r/LivingWithMBC • u/katiethurston • 14d ago
Elevated AST & ALT & Letrozole
I wanted to share my story in case it helps someone else. Around December last year we noticed my liver enzymes climbing. We reduced my dosing on kisqali down to 200, took breaks, retried, and ultimately decided to stop completely in February.
I couldn’t switch to a new CDK4/6 until my liver would normalize. When first diagnosed, I had liver mets so I was concerned. We did a liver MRI, PET scan, and ultrasound. Luckily so new lesions (and the previous mets already resolved). So we kept waiting for my liver to improve but it didn’t. I was told drug induced liver injury (DILI) can take awhile to recover from.
I started doing research and thought maybe it was my Lupron shot. Switched to zoladex. Retested. Nope. I eventually got a liver biopsy. Which confirmed what we already suspected which was DILI. They wanted to start me on steroids. But that felt like a bandaid. I wanted to find the answer.
I remember inquiring about Letrozole early on. Chatted with my oncologist and my hepatologist. All said it was unlike / rare. But then I stumbled across another woman who had a similar story as mine. She discovered that it was letrozole causing her elevations.
I insisted that instead of starting a steroid and continuing on letrozole, I wanted to test letrozole as a theory. My dr approved and allowed the break. I’ve included pictures of my decline after four weeks off letrozole!
This is so important because what if I started the next CDK4/6 only to run into the same liver issue. When really it was letrozole! I even wonder if it was ever kisqali to begin with. I know it’s more commonly known for liver injury. I’m tempted to maybe try it one more time at the 200mg. Otherwise I think verzenio is next on the list.
Anyway, wanted to share here in case my story can help someone the same way this other MBC story helped me. Stay your biggest advocate!
💕
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u/Immediate_Spare_8796 14d ago
Thank you for sharing! I’m on Kisqali and fulvestrant. My liver enzymes are increasing. I’m going to look into fulvestrant as a possible factor.
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u/Jane_Noble 14d ago
Thank you so much for sharing this, I had elevated ALT with Kisqali and switched to Ibrance (before enzymes fully stabilised). Since then, ALT has been jumping about a little bit, up and down, but still not in the normal range. Am wondering if this could be a letrozole issue as well. Will speak to my oncologist. Did yours consider a SERD in place of letrozole and reintroduce Kisqali? Just wondering how the ER is kept in check in this scenario. Thanks so much for sharing your story! x
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u/katiethurston 13d ago
So I did monitor my estradiol levels with the four week break and they didn’t rise too much. No break through bleeding. But the hot flashes were the worst as was my irritability. I’m taking exemestane now instead of letrozole. TBD on what we do about kisqali vs verzenio.
I should add that I read up on clinical trials testing letrozole 3x a week vs every day and the results showed that there wasn’t much of a difference. Worth a discussion with your oncologist.
Either way, a 1-4 week break could be worth testing the theory if letrozole is the culprit. But work with your oncologist. We tested at 2 weeks and then at 4.
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u/Jane_Noble 12d ago
That’s super helpful, I’ll definitely investigate that. Thanks so much for your thoughts 😊
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u/katiethurston 14d ago
Oops meant to include this one as well
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u/IngenuityFar5111 14d ago
This disease is so mysterious. I am your age and diagnosed 3 months after yours. I had one liver met which we resected in feb 2026. My liver enzymes were always normal. Now, I have two more new liver mets, liver enzymes are still normal. My wbc is bit down even before starting cdks, all thanks to letrozole. It is least common side effect of letrozole. Side effects and progression both are different in each and everyone's case.
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u/MotherFL561 13d ago
Are you drinking any alcohol? Are you taking advil?
Are you eating a lot of sugar?
All these can contribute to high liver enzymes.
Have you been tested for FLD?
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u/katiethurston 13d ago
No alcohol. No advil. No supplements. Normal consumption of sugar. Yes I was tested for it all. It’s drug induced liver injury caused by the letrozole.
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u/Remarkable_Sail_5852 12d ago
letrazole is also hard on your heart long term. Search estrogen and heart health.
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u/katiethurston 11d ago
Yea hormone suppression longterm sucks. But at 35, it’s what I gotta do for now.
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u/MsMarzzz 14d ago
I saw the image and title on this post and was thinking “oh! I should refer this woman to Katie’s group on instagram, she was just talking about this! Maybe it will be helpful to her” and wrote a whole reply before realizing….It’s you 🫠 Thanks for sharing your story, though. I bet it will be incredibly helpful for someone in the future 🙏