PALBOCICLIB and LETROZOLE--Can the cocktail cause anemia in advance breast mets?

My Palbociclib and Letozole cocktail has worked over seven years.  I recently lost my appetite and have no energy.  After I whined a bit and my family called the oncologist at a blood tes, they finally checked my hemoglogin, which dropped to five.  They admitted me to the hospital for a day and injected two units of blood transfusion which got mhemoglobin up to seven.  I am still a bit weak and wish I had received a third bag of blood.  I have had mets in the bone, which have been stable over this past 7.5 years.

My anemia and lack of energy is getting me down.  I don’t know what happened to my appetite.  Has anyone been through this.  If my marrow is messed up, can they get me some marrow that works? Anyone know what happens next??  I have a bone biopsy this next thursday and a physical and blood draw prior, as well as a Covid test.

Any thoughts or simolar situations?


Im surprised they haven’t been keeping an eye on your blood test results each cycle of pablociclib because if certain values drop too much they tend to discontinue or reduce the dose for a while. When you mention the actual level your haemoglobin has dropped to it does seem very low so maybe they can look back on any blood tests results they have got to see whether this happened recently or over time. 
Your oncologist may want to do further investigations to see if your mets (you don’t say where they are) have progressed which could be causing the loss of appetite and maybe the drop in your haemoglobin. As to treatment to increase production of red blood cells I am not aware of anything other than blood transfusions to boost them (although someone else may know more). 
Id suggest an appointment with your oncologist to discuss this in more detail to find out what and when this has all happened. It’s good you’ve had so long on this combination of drugs. Are you in the UK as it’s not been available here for as long as that, unless you were on the original trial I presume?

Good Morning,  I’m on this cocktail and must say all my levels are checked now every 3months before I am given any more.   When I started on them I was seen by the nursing team every month as first cycle I was neutropenic!  So far I’ve been on them for a year so it is good to hear you have been on them 7 years.

I think an appointment with oncologist asap.

Thinking of you:) and hoping your energy levels are back soon

Hi Redfish,

Sorry to hear you’ve been feeling so tired and ended up with anemia! 

I was looking into this yesterday - I am not on the same meds as you but I was on Palbo / Letrozole from Feb to May this year before moving onto Capecitabine in June.  I get copies of all my blood test results every cycle.  I noticed that since starting treatment for mets, my blood results have shown significant changes that look like the onset of anemia.  However when I queried them, I was told the changes were “borderline” and not to worry about them!

I don’t like being told things are “borderline” because I’d rather work proactively to prevent rather than wait until I might feel unwell.  I did a lot of reading up on this and there is clinical research available that shows cancer medications can and do cause anemia.  Palbociclib is one of them and can cause a specific type of anemia, here’s a link I happened to find:

Reading up on anemia generally, it looks like iron, B12 and folic acid are what are generally prescribed as supplements to help the body cope (outside of blood transfusions).  Its worth having a conversation with your Oncologist and / or GP about whether or not you should take any.  That’s what I plan on doing and if I gather any further useful info I’ll be sure to share it. 

I hope you are able to speak with your Oncologist and get a good resolution to it!

Hi Redfish,

**ps. I am not any medical

Anemia is one of the side effects palbociclib.


But, should you have regular blood test like every 3 cycles and such, the development of anemia could be monitored?


(just my thought), I am having herceptin for long term treatment. I understand from my onco if a s/e doesn’t appear at the beginning, it is quite unlikely it will develop so much later. 7.5 years on pablociclib . I am receiving treatment in Canada. Just to share the below information which is from BC cancer regency of Canada Health Authorities and hope it helps.