Very low ER positive MBC

Does anyone know anything about the treatment of very low estrogen positive MBC? I was on arimidex for three years before my MBC was diagnosed, and during that time the ER went down from 99 percent to 2 percent. I have been put on ibrance and faslodex. I know this treatment is designed for ER positive tumors, and my oncologist said it is used no matter what the positivity rate. But my question is, is it likely to work?

I have done one full month of ibrance. I had to stay off it for an extra week because I was neutropenic, and then I was off for another extra week because it takes five days to get my test results to me, and by that time someone close to me was sick, and I did a covid test. So I have done three weeks on, three weeks off, and now I'm a week and a half back on. My tumor is on my clavicle, so it's palpable, and believe me, I palpate it all the time. It does not seem to have changed at all. Should it have? How long does it take to start showing results? I'm just concerned that the low estrogen receptor levels will make it all for nothing.

And then what?

Thanks,

Sharon

[Southside25]

I can't speak to the efficacy the meds on a low-estrogen tumor, only my experience on these drugs. I've been on Ibrance/letrozole for about 28 months. In addition to the tumor, I had one lymph node affected and spinal mets. I started on 125 on the recommended 21/7 schedule. I also had problems with low neutrophils and thrush. Onc reduced dosage to 100 and I asked to go down to 75 which I've been on for well over a year. I also am on a 5/2 schedule with no break. From what I've read, it's better to be on the Ibrance on a consistent basis with as few long breaks as possible. My neutrophils have been within the normal range once dose was reduced. The mass is still there, but it has shrunken significantly and at my last PET in March, there is no active hypermetabolic activity anywhere. Node is clear and spinal mets are gone. (I also get Xgeva shot quarterly.) I would certainly give it some time for results, at least a couple of months. If you have some improvement at your next scans, ask to reduce the dose. It seems that if the Ibrance works, it works regardless of dose.

[kearnan]

I could not give you advice. One thing I learned is that everybody reacts differently to all sorts of treatment. You should ask your onco. Some of us have other health issues or on different meds and such. I don't think a month is a long time. But although I am not on it (I am on Verzenio), I know from other forum boards women who have been on it for over 3 or more years.

[Bubbles001]

Do you have any PR positivity? That could be why he kept you on the drug. I don’t think it hurts to continue and see if you respond. I hate being taken off drugs too soon, personally, because you can’t go back. My receptors have changed several times. It’s very confusing to figure out how to treat them. You could get a second opinion for peace of mind.

[Hidden in reply to Bubbles001]

My ER positivity is 2 percent, so very very low. My previous oncologist from out of state saw my biopsy results before I did and said my cancer was now behaving like it was triple negative. I know they do ibrance on any ER positive, but I'm worried that it is less likely to work. I know triple negative is much harder to deal with and has a different treatment. I'm just worried.

[Bubbles001 in reply to Hidden]

I had skin mets that turned out to be triple negative even though my breast and liver and bone tumors were ER+. You can have different cells at the same time. I was pulled off of ibrance and put on Tecentriq, an immunotherapy, and the skin mets completely cleared up. This was a year and a half ago. A lot of the interesting research is happening with TNBC, so it’s not the dire diagnosis it used to be. My liver mets are er/P.R. positive but two years ago, were Er+/P.R.-. I can’t go back on ibrance after only being on it 4 months since I technically progressed, and I’m disappointed. Anyway, it seems like the oncs are just guessing on treatment after a certain point.

[Hidden in reply to Bubbles001]

Progesterone is 70% positive, which the path reports as “weak to intermediate.” 🤷🏼‍♀️ Nobody seems to pay attention to progesterone from what I have seen. How was the tecentriq?

[Bubbles001 in reply to Hidden]

Tecentriq was easy for me and I was on it for 9 months. No side effects at all. I took it with Olaparib/Lynparza because I’m BRCA2 positive. You would probably take it with Abraxane (I think) which I have not tried. I’m on Keytruda now and after five months, I’m having trouble with low fevers. I’m looking forward to getting off Keytruda. Every time we change drugs, it is hard to deal with. I hope your new treatment works for you, but if not, there are other drugs to try.

[brake4country]

Yes, cancers can morph. Sounds like you might be triple neg. How about PR? What is the percentage on that hormone? There are several treatments for trip. neg if you fall in that category.

[Hidden in reply to brake4country]

Progesterone is 70% positive, which the path reports as “weak to intermediate.” 🤷🏼‍♀️ Nobody seems to pay attention to progesterone from what I have seen.

[PLASEM]

Yes, my cancer keeps mutating from positive to negative on my last biopsy ER low percent of positive and my oncologist said that is triple negative

[Hidden in reply to PLASEM]

What kind of treatment do they recommend?

[PLASEM in reply to Hidden]

Chemotherapy

[PLASEM in reply to PLASEM]

To be considered triple negative ER, PR and HER2 needs to be negative but if your PR is 70 percent still positive You still going to be used Hormone blocker like Letrozole sometimes the health insurance do not approve the medication I hope your treatment works

[viennagirl]

I am diagnosed with ER positive mbc but not sure how it differs from other mbc like HER2 positive and others. I always thought I was HER2 but I recently asked my new doctor and she said I am ER. I take Ibrance and Letrozole and it only took a few weeks and I had a reduction in a lump I had on my rib. I would palpate it every day and it just kept getting smaller at an amazing rate. Of course the other metastases were in places I could not touch but my markers also started to recede. However, they are now up a bit to 44. I still think I am doing quite well on the Ibrance/Letrozole combination. I usually feel quite well, just tired occasionally so I make an effort to nap or rest in the afternoons. I don't mind the isolation from the COVID19 because it gives me an excuse to stay home. Some of my friends don't treat me as if I am sick and that sometimes means they don't understand when I want to be alone. So I have to remind them that I need to rest. I think Ibrance is quite an effective drug so believe you should give yourself time to adapt to it. I take it in the evening so I have the whole night to absorb it. I wish you the best. Hugs Marlene

[Hidden in reply to viennagirl]

I know it’s a good drug, just not sure if it will work for my cancer because my estrogen receptors are so low. I also have no tumor markers and I have lobular cancer, which is hard to see in scans. Even the tumor they know is there did not show up on a PET scan. So I am literally working in the dark, and just worried. I guess I am hoping someone will say they had very low ER positive cancer they was eliminated by ibrance! Or anything else!