How does chemotherapy affect dementia?

That’s a tough place to be. My husband has prostate cancer that’s metastasized to his bones. He’s made it very clear that he doesn’t want conventional chemo & I respect that decision. The effect on quality of life would be significant. For 13 years the cancer was held back by radiation, injections, and oral chemo meds. They have stopped working. He has had palliative radiation (will not do that again) & is currently getting monthly bone strengthening infusions (which he is tolerating very well). These last 2 treatments are just to try & reduce the tumors a bit & lower risk of painful bone fractures. They will not lengthen his life by much but should improve quality of life by keeping him out of a skilled nursing facility & contentedly living at home. Talk with your wife if she is still able to communicate. Discuss what is important to both of you - longevity vs quality of life. Ask her care team about the specific side effects & consider her ability to cope with them mentally & emotionally (not just physically). How would treatment affect your ability to care for her? Then make a decision that is right based on your lives & the goals you still share.

Thank you very much for your response. My wife's cancer is multiple myeloma which is cancer of the bone marrow (blood). The cancer was diagnosed in 2017 and she has been on Pomalyst, a chemo drug. with known side effects we have experienced over the years. A risk of multiple myeloma is weakening of the bones. My online search this morning indicates that the brain fog (short term memory loss) can be associated not only with dementia but with long Covid too. My wife tested positive for Covid in February 2023 and was diagnosed by a geriatrician in June 2023 with moderate dementia. She is in a memory care facility now. Long Covid is relatively new. Therefore, it is challenging to separate the independent effects of treatments of dementia and long Covid (2023) along with the side effects of chemo for cancer (since 2017). I appreciate your discussion of choice between living longer and the quality of that life. Long Covid and dementia are the newbies of 2023 whose effects we are trying to understand!

@cuyler, I think you're asking, can chemotherapy makes my wife's cognitive impairment worse? Or are you also concerned about how a person with dementia will manage treatment like chemotherapy?

These are both really good questions to discuss with your wife's oncologist. Some chemotherapy drugs are more likely to cause brain fog than others, not every chemo drug does. What chemo drug is being recommended for her?

Is your wife worried about getting treatment? Or confused and anxious about getting IV chemo? Or is her chemo regimen oral?

My wife was diagnosed with multiple myeloma in 2017. She has been on the cancer drug, Pomalyst. We are familiar with side effects of Pomalyst. The dementia diagnosis was July 27, 2023. To enjoy her birthday and the holiday season, we took her off Pomalyst. Now, we are concerned that the return to Pomalyst will cause side effects and along with dementia will reduce her quality of life.

Sounds like the proverbial "finding yourself between a rock and a hard place." That's a tough choice. If the side effects reduce quality of life, could she take another drug holiday?

My wife has stage 3 kidney disease because of the cancer. She wants very much to avoid dialysis. I am grateful that the cancer drug holiday over the Christmas season did not seem to affect kidney function based on yesterday's phosphorus and basic metabolic panel. We are trying music therapy for the dementia.

You might find this discussion by @gingerw who is also dealing with kidney disease and cancer medications. It's a fine balance.
- Kidney function and medications https://connect.mayoclinic.org/discussion/kidney-function-and-medications/