It's well-known that chemotherapy often comes with side effects like fatigue, hair loss and extreme nausea. What's less well-known is how the cancer treatment affects crucial brain functions, like speech and cognition.
For Yolanda Hunter, a 41-year-old hospice nurse, mother of three and breast cancer patient, these cognitive side effects of chemotherapy were hard to miss.
"I could think of words I wanted to say," Hunter says. "I knew what I wanted to say. ... There was a disconnect from my brain to my mouth."
Before getting treated for cancer, Hunter led a busy, active lifestyle. But the effects of chemotherapy on her brain made it difficult for her to do even the most basic things.
"I couldn't even formulate a smile. I had no expression," she says. "I might feel things on the inside, but it didn't translate to the outside. ... It literally felt like you were trying to fight your way through fog."
Some cancer patients call this mental fog "chemo brain." And now researchers are trying to quantify exactly what chemo brain really is.
Oncologist Jame Abraham, a professor at West Virginia University, says about a quarter of patients undergoing chemotherapy have trouble processing numbers, using short-term memory and focusing their attention.
Using positron emission tomography, or PET, scans to measure blood flow and brain activity, Abraham looked at the brains of 128 breast cancer patients before they started chemotherapy and then again, six months later.
On the second brain scan, he found significant decreases in brain activity in regions responsible for memory, attention, planning and prioritizing. Those results were recently presented at the Radiological Society of North America meeting.
Chemotherapy "can cause damage to bone marrow, hair cells, mucosa," Abraham says. "In the same way, it can potentially cause changes in the brain cells, too."
But Max Wintermark, a brain imaging specialist at the University of Virginia, says the findings bring up more questions than answers: Do brain changes occur with all types of chemotherapy or just one type? Do they only happen to breast cancer patients or to all cancer patients?
Wintermark says these are critical questions that warrant further study.
In the meantime, Wintermark says there are some simple ways cancer patients can work around "chemo brain": reminders on sticky notes and detailed grocery lists.
And fortunately, Abraham says chemo brain is almost always temporary. He says patients usually regain their full cognitive abilities within a year or two after chemotherapy treatment ends.
RENEE MONTAGNE, HOST:
This is MORNING EDITION, from NPR News. Good morning. I'm Renee Montagne.
DAVID GREENE, HOST:
And I'm David Greene. Let's turn, now, to some research that may help cancer patients understand what they're experiencing during chemotherapy. There's fatigue, nausea and other side effects, including one commonly called "chemo brain." Patients describe feeling as if they're in a mental fog. As NPR's Patti Neighmond reports, researchers say they've now detected physical evidence of chemo brain.
PATTI NEIGHMOND, BYLINE: Yolanda Hunter, 41 years old, is a breast cancer patient. She started chemotherapy about this time last year. Around the third day, she noticed she was having a hard time concentrating.
YOLANDA HUNTER: I couldn't think of words that I wanted to say. I knew what I wanted to say. There was a disconnect from my brain to my mouth. In the beginning, I couldn't even remember which words I wanted to say.
NEIGHMOND: A big change for Hunter, a high-powered hospice nurse who also worked a couple of part-time jobs, went to school and with her husband, cared for her three children. For someone who also loved to laugh and joke, this was hard.
HUNTER: I had a lot of where I couldn't even formulate a smile. I had no expression. I might feel things on the inside, but it didn't translate to the outside. It - literally- felt like you were trying to fight your way through fog.
NEIGHMOND: Oncologist and breast cancer specialist Dr. Jame Abraham is Hunter's doctor. He says about a quarter of breast cancer patients who go through chemotherapy, suffer similar problems.
DR. JAME ABRAHAM: Short-term memory, numbers, attention span; those are the things we - usually, we see impaired by chemotherapy.
NEIGHMOND: So using PET scans to measure blood flow and brain activity, Abraham looked at the brains of 128 breast cancer patients before they started chemotherapy, and then six months later. After chemo, he found significant decreases in brain activity; in regions responsible for memory, attention, planning and prioritizing.
ABRAHAM: Chemotherapy causes damage to the normal tissues, in addition to killing the cancer cells. And it can cause damage to the bone marrow, the hair cells, the mucosa. So in the same way, it can potentially cause changes in the brain cells, too.
NEIGHMOND: Further research needs to confirm the findings, and pinpoint exactly how chemo might cause these changes. Radiologist Max Wintermark is a specialist in brain imaging at the University of Virginia.
DR. MAX WINTERMARK: Is it a matter that the neurons, or the brain cells in some regions of the brain, are more sensitive than others? Is it that there are some receptors on the surface of those cells, that respond to those chemotherapies?
NEIGHMOND: Do brain changes occur with all types of chemotherapy, or just one type? Is it only breast cancer patients, or all cancer patients? In the meantime, he says, patients on chemo can benefit from some of the things study participants did - reminders on sticky notes, lists for groceries.
WINTERMARK: Something simple, like instead of going to the grocery store and trying to remember, on the spot, what you need to buy for the different meals you are going to prepare - but instead, preparing a list; preparing it, perhaps, with your loved one before you go to the grocery store.
NEIGHMOND: And the good news, says oncologist Abraham: Chemo brain is often reversible, a year or two after chemotherapy has ended. For Yolanda Hunter, it's been about nine months.
HUNTER: There are times that I still have to think about what I say before I actually speak it. But for the most part, that has gone away; and I'm able to communicate what I would like to communicate, to the person that I'm speaking to.
NEIGHMOND: Hunter says she's still not back to normal. She has to speak slowly, and think about what she's saying. This could be, she says, her new normal. But her doctor, Jame Abraham, is confident that day by day, month by month, her memory and ability to concentrate will improve.
Patti Neighmond, NPR News. Transcript provided by NPR, Copyright NPR.