Staying on Ibrance & Anastrozole after 2 recurrences

[Merma]

I’ve been on Ibrance and Anastrozole for the last 6 years for metastatic endometrial cancer. I started out on the Ibrance125 mg and after a couple of years, had a problem recovering on the week off, so my dose was reduced to 100 mg. By spring this year, the counts could not recover on the week off, so I ended taking more and more time off. One cycle I had to stop at the end of the second week. My Dr was out of town and no one change my dosage. When my Dr came back, he still didn’t want to change my dosage.

In Sept, I had a recurrence. So for the month of September, no Ibrance - just Anastrozole while I received radiation at the recurrence site and also got a lung biopsy. The results were that the cancer was so not solid and there was not enough for molecular sequencing nor a ctDNA. The lung biopsy came back not cancer and not solid.

Since there is no proof that there are any molecular changes, I was put back on Ibrance 100 mg. Again, I had to take 2 weeks off at the end of the cycle. And the Dr insisted that we try this dose for one more cycle. Again 2 weeks off. So he finally switched me to the 75 mg dose.

At the Dec scan, the lung nodule had more uptake. Biopsy happened a week and a half ago. Now it’s the same cancer. I am on 75 mg of Ibrance until the molecular testing comes back and says otherwise.

I’m a bit conflicted. I believe the cancer recurred because I was off of it for too long (Dr agrees). On one hand, I’d rather stay on Ibrance and the ai as long as my blood counts recover between cycles. It has few other side effects (and one good one - keeping the gray hairs away). On the other hand, it could be not enough Ibrance to keep the cancer away. It might be better to go on fulestrant or imlunestrant now as a precaution.

Has anyone been in this position?

[Half-Full]

These are impossibly difficult decisions to make and there really are no right or wrong answers, but you’re asking all the right questions. All I can offer is how my wife and I would have tried to navigate the situation you’re in.

She got 2 years out of iBrance and ended up with severe pneumonitis and ILD lung issues that never fully resolved. Your 6 year run without any ILD is terrific. She also had to gradually reduce her dosage down to 75mg to tolerate it.

From my perspective, and our oncologists generally agreed with this, more often than not when progression is found it’s due to the cancer evolving as opposed to not taking high enough doses at frequent enough intervals. Trying to suffer through the side effects of higher doses or shorter breaks when you already have toxicity and you’re already showing progression on a longstanding treatment will surely result in degraded quality of life. While no one can say with certainty that it wouldn’t help, there’s likely a greater chance that it would not. And then you’re left with more progression in your lungs that more often than not will never be completely reversed.

So if we were in your situation, assuming there are other viable options for you, we would likely be looking at changing iBrance to a different treatment sooner rather than later.

These are really tough decisions to make but I’ve never seen any medical papers or posts that speak of progression being stopped or reversed by simply increasing the frequency or dose of the same treatment that allowed the progression to occur. You’re experiencing toxicity and progression, so we would be looking at other options if we were in your position.

I hope this is somewhat helpful and I wish you the best as you try to navigate these crossroads.

[Merma in reply to Half-Full]

Thank you for your perspective. I guess we have to see if the mutations have changed. So far, it doesn't look like they have, in that case, the recurrence would really have been caused by being off Ibrance and only on the ai. I'm thinking it would be better to switch to a SERD with the 75 mg Ibrance if that's the case.

[Merma in reply to Half-Full]

Hi again,

I thought I'd share an update - got the results of the Pan-Cancer Panel. Although more mutations showed up than I had in 2017, they were supposedly not all that significant. "No variants detected with strong evidence (AMP Tier1) as therapeutic, prognostic, and/or diagnostic biomarkers in this tumor type."

And about Biologically Relevant Variants: "These are known or suspected to be oncogenetic/pathogenic but, at the time of this report, do not have strong evidence for use as therapeutic, prognostic, and/or diagnostic biomarkers in this tumor type."

So, my doctor is keeping me on 75 mg. Ibrance and on anastrozole. I thought he might put me on a SERD, but he wants to wait a little longer (to the next recurrence?). Next PET/CT scan is in April. Hoping for no surprises.

[TammyCross]

Those of us here have metastatic breast cancer. Hard to advise on endometrial. Perhaps it is the same? If it were mbc, it might be good to try Kisqali instead of Ibrance, and a different AI or a SERD, like fulvestrant.