Your Brain On... Chemotherapy

Dr. Ayesha Sherzai (0:00)

Welcome to Your Brain On, the podcast where we explore the neuroscience of everything. I'm Dr. Ayesha Sherzai. Today, we're talking about chemotherapy and the brain. If you or someone you love has gone through cancer treatment, you may have heard the term chemo brain. It's a phrase used to describe the memory lapses, slow thinking and mental fog that so many patients experience during or after treatment. And for years, it was brushed off, called anecdotal or explained away as stress. But today, we know better. The brain is affected by cancer, by chemotherapy and by everything that surrounds it. The fear, the inflammation, the disruption of certain hormones, sleep, identity and so much more. This episode is about understanding what's really going on in the brain during cancer treatment, what the science actually tells us, and where it still falls short. And most importantly, how people can get better. Let's start with what we know and what we don't. Studies suggest that about 75% of people undergoing chemotherapy experience some form of cognitive dysfunction. For about a third, those changes last beyond treatment, sometimes for months or even years. What does that actually look like? It looks like slower processing, difficulty concentrating, having word finding difficulties, trouble with multitasking or having difficulty with short-term memory.

A lot of people describe it as feeling like they're moving through mud, mentally foggy, emotionally flat and cognitively blunted. The term chemo brain suggests that chemotherapy is the sole cause, but the truth is it's more complicated than that. Cancer-related cognitive impairment, or CRCI, is likely multifactorial, which means that there are so many factors involved. Inflammation from the cancer itself, plus the impact of surgery, the anesthesia, the radiation, the hormonal changes for the kinds of cancers that impact the endocrine system all play a major role. Chronic stress in itself can impact the hippocampus and the prefrontal cortex. Sleep is often disrupted, whether it's because of the chemotherapy itself or the pain related with cancer. Other factors that play a role are nutrition, exercise and movement, emotional health, etc. And yes, there are some studies that have shown structural changes in the brain during chemotherapy. We actually have evidence that the gray matter volume decreases, especially in certain regions that are tied to memory and attention. But let's be clear, these findings are often quite modest. Imaging data is limited by sample size, which basically means that it hasn't been tested in a lot of people, the design is variable, and the follow-up period is very short. So we don't have tremendous amount of information in this field, and we can't say with a high degree of confidence that the brain shrinks during chemotherapy. What is more consistent across the literature is functional change and how the different parts of the brain communicate especially under cognitive load. What all of this tells us is this. The brain is adapting under pressure. It's not necessarily damaged, but a more appropriate way to describe it is it's coping. It's responding to systemic stress. And we know from longitudinal studies that many of these changes resolve with time. So neuroplasticity is a real phenomenon, and so is recovery. Earlier this month, Dean spoke with Dr. Liz O'Riordan, a breast cancer surgeon, a speaker, and an author. And she's also someone who's lived through breast cancer not once, but three times. As both a doctor and a patient, she brings a perspective that bridges clinical knowledge with deep human insight. And she's used this experience to educate, advocate, and connect with people around the world. She's fantastic. In 2024, she was awarded the Humanitarian Award from Future Dreams Charity for her work in breast cancer awareness and patient care. Liz's voice matters not just because of what she's been through, but because of what she's built from it.

Dr. Dean Sherzai (4:17)

I would love for you to tell us about your journey.

Dr. Liz O'Riordan (4:20)

Yeah, sure. So for anyone listening who doesn't know me, I was a consultant breast surgeon in the UK. I spent 20 years training to be the best breast surgeon I could. And at the age of 40, I found a lump in my breast. I'd had a couple of cysts before. I never checked them regularly. And I think most people, if we're honest, don't check our cells for cancer because we think it's never going to happen. And my mammogram was normal. I had an ultrasound scan and that showed a large cancer. And in that minute, I knew far more than normal patients. I knew I need chemotherapy. I knew I need a mastectomy. I had a good idea what my chance of making it to 10 years was because it's my job to know this. And it's like something in my brain just switched off. I'm in denial this isn't happening to me, it's happening to someone else. And that's how I process through treatment. I had the full works, chemotherapy, mastectomy, all my nodes out, I had radiotherapy, I was put on hormone blockers. And it took me about a year to recover from all of that and go back to work. But sadly, about two years later in 2018, I had a local recurrence on my chest wall. And the side effects of the treatment for that meant that I couldn't operate anymore. I was forced to resign at the age of 43 And I had no job, I had no hobbies, I had no status, I didn't know who I was. I'm still grieving for so much I lost. And I had a second recurrence a couple of years ago. And losing everything makes you realize who you are and what defines you and what your real purpose is. And mine is to help people and small animals and birds. And I kind of just found new ways to keep doing that by talking, by writing, by doing podcasts, by doing explainer videos. And it's just led to this volunteer doctor for the internet. But it is so rewarding.