Our neurotoxic world (part one): Chemotherapy and the brain

Saturday 10 February 2007 1:00PM

Your brain is a resilient organ, but vulnerable to nasty environmental insults too. This week, in the first of two shows navigating our neurotoxic world: it's been dubbed 'Chemofog' and 'Chemobrain' by cancer survivors: short-term memory loss, foggy thoughts, fatigue - lingering sometimes years after chemotherapy. Could chemo be doing more than killing off cancer cells? New research suggests it may be more toxic to your nerve cells than cancer itself. Natasha Mitchell investigates.


Natasha Mitchell: And hello, welcome to All in the Mind on ABC Radio National -- Natasha Mitchell with you, great to have you on board. And a reminder you can catch the show across Australia on Saturdays at 1pm and again now on Mondays at 1pm -- a new repeat slot for 2007. And of course get us online any time on abc.net.au/rn

Today, 'Our Neurotoxic World', the first of two shows exploring environmental insults on our most precious of organs -- the brain. This week chemotherapy and the brain. We want chemo to kill off those nasty cancer cells but is the toxic cauldron of chemicals just as toxic to your brain as it crosses the blood brain barrier?

Denise Wong: It was quite confronting because I thought am I going crazy, am I going to end up in an old people's home or something with dementia? It's something that we really know is real, the chemo that goes into your body goes through every cell of your body and you can see it physically where you lose all your hair, and your skin is not good, and all these physical things that it does to you. Obviously if the chemo is going through your brain and it's going to do some damage.

Mark Noble: There are stories of problems with memory, simple daily skills that most of us take for granted become somewhat more difficult and in some people become so difficult that their job performance may suffer so much that they end up not being able to work in that job any more.

Natasha Mitchell: Professor Mark Noble and before him Denise Wong. Many survivors of cancer speak colloquially of so called 'chemofog' or 'chemobrain'. Their mind, they say, has distinctly lost its sharpness after chemotherapy and they're convinced that chemo is to blame.

But before you become alarmed, as you'll hear today proving that's the case is far from straightforward.

Janette Vardy: I think for people who don't know people who have had cancer often they would think that this is just, they need to get on with their life. And in fact it was patients that first brought it to attention. In many cases they were the ones that identified it way before the medical profession.

Kelly Phillips: I think the first thing to say is we really owe it to women with breast cancer and also women in the future who will develop breast cancer to really thresh out this problem and figure out what's going on. But at the same time I tend to be a little bit conservative in the way I read the research in that we also need to be careful that we don't leap to conclusions too quickly. We have to remember that chemotherapy for breast cancer is potentially curative for a large number of women.

Natasha Mitchell: Associate professor of medicine and clinician Kelly Phillips from the Peter MacCallum Cancer Centre and before her, medical oncologist Dr Janette Vardy. So what might chemo be doing to the cells of our nervous system?

Mark Noble is professor of biomedical genetics at the University of Rochester Medical Center. As a well known pioneer in stem cell research, that's just his concern.

Mark Noble: What really had me curious was that we actually know a fair deal about the damage done to the brain by radiation but virtually nothing about the effects of chemotherapy. As one sees cancer patients surviving for longer periods of time we are recognising that some proportion of cancer patients, and for those receiving high dose chemotherapy, it may be as high as 30% of them are actually having neurological problems, cognitive problems.

Natasha Mitchell: Has it been underestimated, or ignored perhaps even, in research circles?

Mark Noble: It was never underestimated by the paediatric oncologists because they were seeing many of the children they had treated come back with serious problems, particularly the children who were getting treated with chemo-therapeutic agents and radiation in the brain.

Natasha Mitchell: Well down the track kids were having problems?

Mark Noble: Well down the track -- years down the track. In the context of the treatment of adult patients there was a failure to recognise this. What has helped to change that is the unambiguous nature of imaging studies and it's very clear that in a high proportion of patients -- in one study, 70% of patients -- getting high dose chemotherapy show clear changes, sometimes emerging a year or two after treatment.

Natasha Mitchell: Professor Mark Noble and more on his team's recent sobering study in just a moment.

Janette Vardy: Early on it was very much thought that it was all in the mind, that it was probably due to hormonal changes, because it was mainly being talked about in women who were being treated for breast cancer. And often if they have chemotherapy and they're younger they go through an early, abrupt menopause. So it was put down partly to that and also to anxiety stress.

Natasha Mitchell: Janette Vardy is a medical oncologist at the Sydney Cancer Centre and a fellow with the NSW Cancer Institute.

Janette Vardy: There was very little in the literature about this until probably ten years ago, and then the first of the better quality studies started coming through. And since then there's growing evidence that this is a real phenomenon.

Natasha Mitchell: And it's not just women, men experience it too?

Janette Vardy: Exactly, so we're doing some trials at the moment in colorectal cancer.

Natasha Mitchell: Well let's get to the heart of what we're talking about here. Not everyone reports they're having troubles with their thinking during or after chemo but some clearly do. Well what do you hear from patients, give us some anecdotes.

Janette Vardy: The typical story is that people will say that whilst they're on chemotherapy that their memory and concentration is not as good as it was previously. And for most it goes away when they finish chemotherapy with a little bit of time. But for a subset they give a very clear story of problems that continue on, and in some cases for many years after having chemotherapy.

Natasha Mitchell: Dr Janette Vardy. Denise Wong can relate -- she was diagnosed with breast cancer in 2003. Her busy life with two children and a home business was thrown into chaos.

Denise Wong: Ironically it was during breast cancer week. One night I was actually just lying on my bed, I had my arm up over my head scratching the back of my neck. I was feeling in the pit of my armpit, quite deep inside, and I found this lump by chance and booked an appointment to see my GP. She did a breast examination and she felt the lump and she said look, I'm going to send you for some tests only because I can feel a firmness under your nipple and she said it may be related but don't be concerned.

Natasha Mitchell: You did go and have a proper check up and the news was not good. In fact what you'd found under your arm was the secondary tumour wasn't it?

Denise Wong: Yes, that's correct so it had gone from the breast to the lymph glands.

Natasha Mitchell: You were told that it was too late for surgery, what went through your mind when your doctor said that?

Denise Wong: Oh, I felt like the floor had just fallen out of the room. It was quite dangerous to operate in that area because the lymphatic system is like the highway to your whole body so disturbing that area with surgery could spread the cancer quite quickly.

Natasha Mitchell: Chemo -- you were booked in for very strong chemo throughout all this? You were told about side effects like nausea, like fatigue but were you told about this what's been colloquially called chemobrain, something that you've gone on to experience? Were you given any inkling that this might be an issue, the impact of chemo on your mind?

Denise Wong: Not at all. The doctors, they didn't sort of mention that they mainly focus on the physical aspect of the treatment and what you'll endure and even in the information sheets there wasn't really anything on chemobrain or forgetfulness, or loss of memory. And I suppose chemobrain is secondary because you're so focused on surviving and dealing with the physical aspects that chemobrain isn't really recognised until later when you get back to normal life.

Natasha Mitchell: Do you have patients who come to you and say, I think I've got what they call chemofog or chemobrain?

Kelly Phillips: I certainly do, and more so of recent times when this has become wider known in the breast cancer community. My sense is that the perceived prevalence in breast cancer survivors seems to be higher.

Natasha Mitchell: Associate professor of medicine Kelly Phillips from the Peter MacCallum Cancer Centre. She's the Colebatch Clinical Research Fellow with the Cancer Council of Victoria. Her speciality is breast cancer.

Kelly Phillips: And so there's a question about how much of that is real or how much of it is about people being super-sensitive to their cognitive function after they've had breast cancer treatment. Because in fact many of the lapses and problems that these women describe are the sort of lapses and problems that you and I often have probably in our daily lives as well but we may just be less aware of them and less sensitive to them.

Natasha Mitchell: I have lots of lapses and problems and I haven't had chemo I must say.

Kelly Phillips: Yes, me too.

Natasha Mitchell: Certainly though we can't underestimate the impact, even just a minor shift in our memory can really have a profound impact on our lives, can't it?

Kelly Phillips: Well I think that's definitely true and the other thing that we have to remember in breast cancer is that many women who are affected with breast cancer are youngish, they've got young families that they're trying to deal with, they're also trying to work so they are multi-tasking and they've got a fair bit of stress on their cognitive function already. So even subtle changes in their cognitive function could mean really big impacts on their day-to-day life.

Natasha Mitchell: Medical oncologist Kelly Phillips, who isn't entirely convinced that chemo is the culprit for the mental fog that some people report after cancer treatment.

Denise Wong: Sometimes even situations where you have to for a moment stop and go OK, where am I -- which is quite scary just for that split second.

Natasha Mitchell: So it's like a blanking out?

Denise Wong: Yes, it's just like for a moment just being blank. It's short-term memory loss; meeting people and forgetting names that's quite frustrating, forgetting names and probably a narrowing of my vocabulary, it's just harder to express yourself and your thought processes are a lot slower.

Natasha Mitchell: This is three to four years after you were diagnosed now though, so you're still experiencing this?

Denise Wong: Yes I do and you know some people will even say it's just because you're getting old but it is quite significant and noticeable. Writing down lots of notes, I didn't used to have to do that but now I have to note everything down. Within the big picture it doesn't sort of matter, it's just something that I can share with other survivors, we joke around about it. It's a good thing to blame when you do something silly or you forget something, you know just blame it on the chemobrain.

Natasha Mitchell: Denise Wong here on ABC Radio National. Natasha Mitchell joining you for your weekly dose of All in the Mind on Radio Australia and your pod too wherever you may be.

Today, 'Our Neurotoxic World', part 1. We're looking at the claim that chemotherapy causes mild to sometimes major cognitive problems. Is so-called 'chemobrain' a real phenomenon, or a result of the stress of dealing with the cancer diagnosis perhaps?

Professor Mark Noble from the University of Rochester and colleagues are investigating whether chemo is toxic to the nervous system, starting with mice as their model, they recently published a striking study which, he says, is the first to put chemobrain on sound scientific footing.

Mark Noble: Well what we did is we have a team that has been involved in the discovery of a number of the cells that are the building blocks of the brain. So the first question that we asked was were these cells in a tissue culture dish vulnerable to the effects of chemotherapeutic agents? And we looked at standard agents that are used; a nitrosourea called BCNU, Cisplatin, and another drug called cytarabine.

Natasha Mitchell: Common chemotherapy drugs?

Mark Noble: Common chemotherapy drugs. And what we found is that the progenitor cells that are the workhorses of building a tissue that do most of the division in building a tissue. And another cell type called an oligodendrocyte. The oligodendrocyte is the cell that makes the insulating sheaths that surround the axons of the nervous system. And these insulating sheaths called myelin are essential for normal impulse conduction. What we found is that the progenitor cells of the oligodendrocytes were very sensitive to the effects of chemotherapy and in fact in many instances were more vulnerable to these agents than a number of cancer cells that we studied.

Natasha Mitchell: And even at very low doses?

Mark Noble: Even at very low doses, below those that are routinely achieved in the clinic, we saw a reduction in cell division for example. But then the question is does that mean anything in the animal? And what we found is that all the cell types that we found to be targets in the tissue culture dish were targets in the animal. So if we gave animals three injections of chemotherapeutic agents -- not in the brain, under the skin for example -- and then looked at what happened in the brain we found reductions in cell division, we found increases in cell death in precisely the cell populations that had been vulnerable in the tissue culture dish.

Natasha Mitchell: That you'd seen in the test tube?

Mark Noble: That's right.

Natasha Mitchell: This is very disturbing, I mean what you're suggesting here -- because you also added these chemotherapy drugs to cancer cells, common cancer cells in a test tube or a dish, and they didn't appear to be as vulnerable. So in fact the nervous system cells were more affected by the chemotherapy drugs than the cancer cells?

Mark Noble: That's right. Now Natasha that's very important to put that in context. Many of the cancer cells perhaps most of the cancer cells that we grow in the laboratory are derived from malignant tumours that have become quite resistant to everything. We've not made good progress on treating malignancy, we've made great progress in treating early-stage cancer.

Natasha Mitchell: Right, OK, so we have to take the results with a bit of caution. Still they give you quite considerable cause for concern.

Mark Noble: They give one cause for concern. And I think that where we are right now is that a number of individuals who have been treated for cancer have been saying for some time, this is a problem. A number of people in the healthcare community who have been studying these patients are saying this is a problem. What we have now done is to say yes, biologically this is a problem; this is how we can study it, here are animal models where we can find now ways of trying to provide protection. What I'm more disturbed by is the widespread damage that we are seeing to myelin sheaths. The breakdown of myelin is perhaps the largest single category of neurological disorder of which we know. It occurs in Alzheimer's disease, it occurs in spinal cord injury, it occurs in multiple sclerosis, it occurs in many developmental maladies and hypoxic birth insults to babies, leading to cerebral palsy.

Natasha Mitchell: These are mice, these aren't humans.

Mark Noble: Yes, these are mice.

Natasha Mitchell: So can you confidently translate what you've seen in mice to humans?

Mark Noble: Well the basic rules of biology are conserved throughout evolutionary history. So the whole basis of medical discovery is the ability to be able to make the leap from one species to another. It has been the case in many, many areas of medical discovery that what we discover in a mouse does translate to the human. And it has been also the case in others where it doesn't translate -- the big question is can we find ways of preventing this damage in the mouse to begin with and if so, does that translate to the human? That'll be the proof of the value of the research in the end.

Natasha Mitchell: Professor Mark Noble. And his team found that the hippocampus for example, the structure in our brain and those of mice that's so key in memory and learning was a target for chemo. Could chemotherapy prematurely age our brains, he wonders?

Associate professor Kelly Phillips from the Peter MacCallum Centre thinks the study is interesting but is doubtful folk undergoing chemo can take anything from it -- yet.

Kelly Phillips: The other issue with that research as I see it is that although the researchers were able to see that there was death of neuronal cells in the mice brains after they'd received chemotherapy we don't really know what effect that had on the mice. There weren't then any studies of the behaviours of the mice to determine whether it was impacted on their cognitive function. And you know we know for example an analogy might be that we know that chemotherapy can affect and kill the mucosal cells in a woman's mouth when she's having her chemotherapy and you can probably see that in all women having chemotherapy for breast cancer, but not all of them get a sore mouth.

Natasha Mitchell: Certainly though, do you think there's been a tendency to treat the body a bit as a black box when it comes to chemo? I mean it's a toxin, it's a poison, people get very sick from it, yes it targets cancer, but there must surely be a host of unanswered questions about its wider impact?

Kelly Phillips: You know in all of the studies that we do when we are trying to come up with new and better chemotherapy regimens and treatments, we do assess toxicities very carefully. But I think the difficulty with cognitive function is it's so difficult to assess that it hasn't generally been included in the battery of assessments that are done in new drug development. That's one of the areas that I have a particular interest in -- you know 20 or 30 years ago we weren't routinely looking at quality of life in these studies either and now we do, and I think cognitive function should be an intrinsic part of those studies.

Natasha Mitchell: Well, Dr Kelly Phillips, you're not convinced that chemotherapy is the whole picture, that gives us the whole story on this chemobrain, are you?

Kelly Phillips: No I'm not. I suspect it probably is a component but the reasons I'm not is because when we treat women for breast cancer we get hormonal changes. So many of these women go through a premature menopause and in addition, many of these women will be treated with hormonal treatments. And my concern is that given that we know that oestrogen is actually really important to cognitive function, there's a large body of literature about that; my concern is that there might also be hormonal components to the cognitive dysfunction that's been seen.

Natasha Mitchell: Some studies have estimated that up to 30% of cancer patients experience cognitive problems after chemo even well down the track. That's a huge figure, that's a third of cancer patients potentially.

Kelly Phillips: It is a huge figure and I think we have to be careful about using that figure because I personally believe it's likely to be an over-estimate. One of the things that's very difficult in this area of research is the way in which you define cognitive dysfunction and the statistical analyses that are used because often these women have had multiple neuropsychological tests as part of the research and so there's the possibility of finding something that's not actually real.

Natasha Mitchell: Or missing something that is real. So it sounds devilishly difficult to strip out the impact of chemo on cognition from everything else that's going on.

Kelly Phillips: Yes, I think that's true. And that's one of the problems with the research that has been done to date. Breast cancer patients that have been involved in the research have been very heterogeneous; so they've been young, old, pre-menopausal, post menopausal, having hormonal therapy, not having hormonal therapy -- all mixed up in the same studies. And because the numbers have been small in all of these studies it then makes it very difficult to try and tease out the influence of chemotherapy versus hormonal therapy, for example.

Natasha Mitchell: A lot of the studies have focused on women, but then men also report cognitive problems.

Kelly Phillips: You are right, I mean this has been reported with other types of cancers and I guess a good example would be testicular cancer. There have been some reports and there are large scale studies under way to try and dissect that out and those other cancer types as well. So you know you're right, that kind of implies that perhaps hormonal factors are not so important.

Natasha Mitchell: The other fascinating thing in all this is that often cancer patients will say yes, my mind's gone all woolly, I can't think as straight, I've lost my cognitive sharpness, my working memory is shot. OK, so that's their subjective report but according to all the measures, the objective measures, they're doing fine. There's this disconnect isn't there; how do you read that?

Kelly Phillips: Well that's right and I think that's one of the very interesting areas of this field of research and the thing that really needs to be addressed. Because in all of the studies that have been conducted to date there's been no correlation. And so what's that all about? Some people have suggested that that might be because in women who do have cognitive dysfunction perhaps it's too subtle to be detected by the tests. But that doesn't explain why in these studies the women that do objectively have cognitive function often don't report any cognitive dysfunction. So it is very confusing and certainly that's another area that needs to be looked at more closely.

Natasha Mitchell: Sydney Cancer Centre medical oncologist Dr Janette Vardy with colleagues in Toronto is studying so called chemobrain and trying to address some of the flaws in previous research. They're conducting two major, large-scale studies following a group with breast cancer and another with colorectal cancer over a couple of years. It's early days in the data crunching but they're seeing early trends. And with the help of brain scans and blood tests the study of breast cancer patients is producing especially interesting results.

Janette Vardy: And what we di is we do a scan of the brain with the woman at rest, we then do the scan while they do a working memory task and we look at what happens in the brain. And then the task varies in that it will become more difficult.

Natasha Mitchell: And what have you seen, it's early days yet but it's very interesting.

Janette Vardy: It is early days, but we've found is there is again, what we call a trend to [there] being differences in areas of activation. So the patients that never received chemotherapy, although they had breast cancer, their functional MRI scan looked much more like what a healthy control person would; so someone who has never had cancer. And then when we looked at the women who had had chemotherapy, there were some differences in activation and in some cases as the task got more difficult they were activating different areas of the brain compared to those who had never received chemotherapy.

Natasha Mitchell: So you're still stripping out what that all means, but it does indicate to you that if someone's had chemo and they're doing a little task in a brain scan, different things are going on in their head.

Janette Vardy: That's right. We're now increasing the sample size so we have already tested over 60 and we are then expanding that to 120.

Natasha Mitchell: Certainly, Janette Vardy, some brain scan research has indicated that damage in both the white matter and the grey matter in the brain that can last for some time after someone's had chemo.

Janette Vardy: That's right.

Natasha Mitchell: How do you find that research, is that robust?

Janette Vardy: Again it's early days in that study. You're actually able to see in black and white some differences. What you don't know is what those differences that you can see on a scan, how they relate to how a person will cope in normal life.

Natasha Mitchell: Dr Janette Vardy. In fact a recent Japanese study found that a year down the track key parts or the brains of women with breast cancer having chemo were reduced in volume. But after three years those areas had appeared to recover. The question of course is had the right cells repopulated the right parts of their brains. If you're undergoing chemotherapy yourself, or know someone who is, you're probably wondering if you should be concerned about chemobrain.

Dr Vardy stresses chemotherapy is a lifesaver, a crucial and carefully studied mainstay of cancer treatment. As does Associate Professor Kelly Phillips.

Kelly Phillips: But I'm certainly interested in trying to work out what's going on when a woman comes into my consulting room and says I can't think straight since I've had my breast cancer treatment.

Natasha Mitchell: OK, so for now what do you tell that woman?

Kelly Phillips: Well I think the most important thing initially is to exclude reversible causes of cognitive dysfunction. And one of the most common reversible causes of cognitive dysfunction in this group of people is depression and anxiety and psychological factors. And then after that I think it's important to normalise the experience for the woman, to say that there are other women who feel this way after their breast cancer treatment, but that our experience and the data from the research suggest that the effects tend to wear off over time.

Natasha Mitchell: Thank you very much to Dr Kelly Anne Phillips for joining us on the show this week.

Kelly Phillips: You're welcome, it was a pleasure.

Natasha Mitchell: And what possibilities do you think there might be for protecting people and protecting their brain cells when they're having chemo? Protecting or perhaps mopping up the damage afterwards?

Mark Noble: I'm actually optimistic about that, there are a lot of reports in the literature on ways of protecting with some very benign substances, the various kinds of antioxidants. And which ones are most suitable for this and which ones are most suitable for use in the brain, what kinds of combinations are best to use is a matter that we have to pursue scientifically. But it's certainly a very promising lead. For us the critical issue is understanding the mechanisms by which we can either kill cancer cells without killing normal cells, or at least give selective protection of normal cells.

Natasha Mitchell: One to watch with keen eyes especially if you're dealing with chemo yourself. Mark Noble there, professor of biomedical genetics at the University of Rochester Medical Center, who says don't underestimate the power of a healthy diet, by the way.

And next week we'll continue this exploration of our neurotoxic world with industrial chemicals and developmental disorders -- and one claim that we're facing a silent pandemic.

You'll find the downloadable audio of the show on our website, podcast it, or save it to your 'puter. Head to abc.net.au/rn/allinthemind and a transcript there later in the week. Email us from there too -- go for it.

Last words go to Denise Wong who isn't officially in remission but optimistic.

Denise Wong: No medical team can guarantee that you're not going to get it again. There may be a stray cancer cell in your body somewhere that's laying dormant and it may reactivate at any time.

Natasha Mitchell: How do you manage that uncertainty?

Denise Wong: I think firstly it's willpower and positive attitude. When you have young children and you want to do anything to survive because you don't want to leave your children without a mother. I think that makes a big difference and ... here's the chemobrain working now, so ... I always have in the back of my mind whenever I have a backache or a headache or anything that hurts, it's a natural thing for a cancer patient to think that the cancer's come back. So [the way] you have to deal with that, I suppose, uncertainty, is to keep speaking to your doctors and getting things checked out.

Natasha Mitchell: Well look I wish you the very best, good luck and thank you for joining me on the program this week.

Denise Wong: Thank you, Natasha.

Natasha Mitchell: And thanks also today to producer Anita Barraud, great to have her with the show for 2007 and to sound engineer Russell Thompson. I'm Natasha Mitchell and don't forget our new repeat times Mondays at 1pm now and if you're a night owl 2am Tuesday mornings. Catch you next week -- look after your head.


Denise Wong
Cancer survivor and patient advocate
Professor Mark Noble
Professor of Genetics
School of Medicine and Dentistry
University of Rochester
New York State Centre of Excellence in Spinal Chord Injury
Dr Kelly Phillips
Associate Professor of Medicine
Peter McCallum Cancer Centre
Jonathan Colebatch Clinical Research Fellow
Cancer Council of Victoria
Dr Janette Vardy
Staff specialist, Medical Oncology
Sydney Cancer Centre
Fellow, New South Wales Cancer Institute


CNS Progenitor Cells and Oligodendrocytes are targets of chemotherapeutic agents in vitro and in vivo
Joerg Dietrich, Ruolan Han , Yin Yang , Margot Mayer-Pröschel and Mark Noble
Journal of Biology, 2006, 5:22
Adjuvant breast cancer treatment and cognitive function: Current knowledge and research directions
Kelly-Anne Phillips & Jurg Berhard
JNCI Journal of the National Cancer Institute, Vol 95, No 3. 2003
Marina G. Falleti, Antonietta Sanfilippo, Paul Maruff, Leann Weih, Kelly-Anne Phillips
Brain and Cognition, 2005, vol. 59, No1
Cognitive Impairment Associated with Chemotherapy for Breast Cancer: A Mechanistic Cohort Study
Christopher Booth, Janette Vardy, Adrian Crawley, Sean Rourke, Gregory Pond, Lynne Wagner and Ian Tannock
Presented in part at the 42nd Annual Meeting of the American Society of Clinical Oncology, Atlanta, June 2-6 2006
Assessing cognitive function in cancer patients
Janette Vardy, Karen Wong, Qi-long Yi, Alison Park, Paul Maruff, Lynne Wagner and Ian F. Tannock
Supportive Care in Cancer, Volume 14, Number 11 / November, 2006
Estrogen, Tamoxifen, and the Brain
P. A. Ganz, S. A. Castellon, and D. H. S. Silverman
Journal of the National Cancer Institute, April 17, 2002; 94(8): 547 - 549
Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5 to 10 years after chemotherapy
Breast Cancer Research and Treatment. Sept 29 2006
Cognitive Damage May Appear After Cancer Treatment Ends
Aaron Levin
Psychiatric News January 5, 2007, Volume 42, Number 1, page 24


Natasha Mitchell
Anita Barraud / Natasha Mitchell