Posts tagged chemotherapy

Breast cancer survivors who had chemotherapy show changes in brain activity during multitasking chores, according to a new Belgian study.

These findings may partly explain the phenomenon dubbed “chemo brain.” For years, people who’ve had chemotherapy have reported changes in thinking and memory, especially when doing more than one thing at once.

"Before you can fix a problem, you need to know what the problem is. And this study demonstrates what the problem may be. It’s a really good first step to understanding the what. Now we need to understand the why and how to fix it," said Dr. Courtney Vito, a breast surgeon and assistant clinical professor of surgical oncology at the City of Hope Comprehensive Cancer Center in Duarte, Calif. Vito was not involved in the current study, but reviewed the study’s findings.

In her experience, Vito said, women tend to be affected more by chemo brain than are men after chemotherapy. However, she said, ”women tend to multitask more, so this might explain part of it.”

The new study was published online May 27 in the Journal of Clinical Oncology.

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For some cancer patients, the mental fogginess that develops with chemotherapy lingers long after treatment ends. Now research in breast cancer patients may offer an explanation. 

Patients who experience “chemobrain” following treatment for breast cancer show disruptions in brain networks that are not present in patients who do not report cognitive difficulties, according to researchers at Washington University School of Medicine in St. Louis.

Results of the small study were reported Thursday, Dec. 12 at a poster presentation at the San Antonio Breast Cancer Symposium.

According to the researchers, many breast cancer patients who receive chemotherapy report long-term problems with memory, attention, learning, visual-spatial skills and other forms of information processing. The brain mechanisms contributing to these difficulties are poorly understood.

The investigators used an imaging technique called resting state functional-connectivity magnetic resonance imaging (rs-fcMRI) to assess the wiring among regions of the brain in 28 patients treated at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University. Fifteen patients reported they were “extremely” or “strongly” affected by cognitive difficulties. The remaining 13 reported no cognitive impairment.

The imaging studies suggest that standard chemotherapy given to breast cancer patients may alter connectivity in brain networks, especially in the frontal parietal control regions responsible for executive function, attention and decision-making.

“Chemobrain is most likely a global phenomenon in the brain, but a set of regions involved in executive control, called the frontal-parietal network, is perhaps the most affected brain system,” said Jay F. Piccirillo, MD, professor of otolaryngology and a member of the research team with expertise in the use of brain imaging to study tinnitus, or phantom noise. “We’re confirming previous studies that also have shown this. And we’re developing a solid multidisciplinary working group at Washington University to determine how we can help these women.”

Other studies also have used neuroimaging techniques to observe the neural disruptions associated with Alzheimer’s disease, depression and stroke. Washington University researchers are beginning to investigate whether cancer patients experiencing chemobrain may benefit from therapies similar to those that help patients with other cognitive disorders.

(Source: news.wustl.edu)

Researchers at UCLA’s Jonsson Comprehensive Cancer Center have developed a new drug delivery system using nanodiamonds (NDs) that allows for direct application of chemotherapy to brain tumors with fewer harmful side effects and better cancer-killing efficiency than existing treatments.

The study was a collaboration between Dean Ho, professor, division of oral biology and medicine, division of advanced prosthodontics, and department of bioengineering and co-director of the Weintraub Center for Reconstructive Biotechnology at UCLA School of Dentistry and colleagues from the Lurie Children’s Hospital of Chicago and Northwestern University Feinberg School of Medicine.

Glioblastoma is the most common and lethal type of brain tumor. Despite treatment with surgery, radiation and chemotherapy, median survival time of patients with glioblastoma is less than 1.5 years. This tumor is notoriously difficult to treat in part because chemotherapy drugs injected on their own often are unable to cross the blood-brain barrier, which is the system of protective blood vessels that surround the brain. Also, most drugs do not stay concentrated in the tumor tissue long enough to be effective.

The drug doxorubicin (DOX) is a common chemotherapy agent that is a promising treatment for a broad range of cancers, and served as a model drug for treatment of brain tumors when injected directly into the tumor. Ho’s team originally developed a strategy for strongly attaching DOX molecules to ND surfaces, creating a combined substance called ND-DOX.
Nanodiamonds can carry a broad range of drug compounds and prevent the ejection of drug molecules that are injected on their own by proteins found in cancer cells. Thus the ND-DOX stays in the tumor longer than DOX alone, exposing the tumor cells to the drug much longer without affecting the tissue surrounding the tumor.

Ho and colleagues hypothesized that glioblastoma might be efficiently treated with a nanodiamond-modified drug using a technique called convection enhanced delivery (CED), by which they injected ND-DOX directly into brain tumors in rodent models.

The researchers found that the ND-DOX levels in the tumor were retained for a duration far beyond that of DOX alone. The DOX was taken into the tumor and stayed in the tumor longer when attached to NDs. ND-DOX also increased programmed cell death (apoptosis) and decreased cell viability in glioma (brain cancer) cell lines.

Their results also showed for the first time that ND- DOX delivery limited the amount of DOX that was distributed outside the tumor and reduced toxic side effects while keeping the drug in the tumor longer and increasing tumor-killing efficiency for brain cancer treatment. Treatment was more effective and survival time increased significantly in rats treated with ND-DOX compared to those given unmodified DOX. Further research will expand the list of brain cancer chemotherapy drugs that can be attached to the ND surface to improve treatment and reduce side effects.

“Nanomaterials are promising vehicles for treating different types of cancer,” Ho said, “We’re looking for the drugs and situations where nanotechnology actually helps chemotherapy function better, making it easier on the patient and harder on the cancer.” Ho adds that a project of this scale has been successful due to the multi-disciplinary and proactive interactions between his team of bioengineers and outstanding clinical collaborators from Northwestern and Lurie Children’s Hospital.

Ho went on to say that the ND has many facets, almost like the surface of a soccer ball, and can bind to DOX very strongly and quickly. To have a nanoparticle that has translational significance it has to have as many benefits as possible engineered into one system as simply as possible. CED of ND-DOX offers a powerful treatment delivery system against these very difficult and deadly brain tumors.

The study appears in the advance online issue of the peer-reviewed journal Nanomedicine: Nanotechnology, Biology and Medicine.

(Source: newswise.com)

The mental fuzziness induced by cancer treatment could be eased by cognitive exercises performed online, say researchers.

Cancer survivors sometimes suffer from a condition known as “chemo fog”—a cognitive impairment caused by repeated chemotherapy. A study hints at a controversial idea: that brain-training software might help lift this cognitive cloud.

Various studies have concluded that cognitive training can improve brain function in both healthy people and those with medical conditions, but the broader applicability of these results remains controversial in the field.

In a study published in the journal Clinical Breast Cancer, investigators report that those who used a brain-training program for 12 weeks were more cognitively flexible, more verbally fluent, and faster-thinking than survivors who did not train.

Patients treated with chemotherapy show changes in brain structure and function in line with diffuse brain injury, and they often report long-term cognitive effects, says Shelli Kesler, a Stanford University clinical neuropsychologist who led the research. The new study “suggests that cognitive training could be one possible avenue for helping to improve cognitive function in breast cancer survivors treated with chemotherapy,” she says.

The results may not convince everyone. “One of the biggest challenges in the cognitive training world is to show an effect that generalizes to real-world functioning,” says Susan Landau, a neuroscientist at the University of California, Berkeley. Several companies offer commercial cognitive training programs that promise improvements in memory, attention, mental agility, and problem-solving skills. The appeal is clear, says Zach Hambrick, a psychologist at Michigan State University in East Lansing, but whether they have lasting general effects is not.

The fact that companies are marketing these training programs to customers before their value has been rigorously proved has caused some skepticism in the field, say experts. “The field is still growing,” says Suzanne Jaeggi, a neuropsychologist at the University of Maryland. While studies have shown that there are cognitive benefits to the training, it’s very hard to detect an impact on daily life, she says. However, some work, including research by her own group, has shown that working memory exercises can improve reading abilities in schoolchildren.

In the study conducted by Kesler and colleagues, the participants trained at home on Lumosity, a collection of gamelike cognitive exercises developed by Lumos Labs in San Francisco. (Lumos Labs did not fund the study.)

Kesler’s project is one of around two dozen efforts using Lumosity software to study human cognition. With 35 million customers worldwide, Lumosity is collecting what it says is the world’s largest database of human cognition, which could be queried for connections between lifestyle and cognitive ability. “Our technology collects a lot of data and makes it easy to run experiments to learn more generally about human cognitive performance,” says Mike Scanlon, cofounder of Lumos Labs. “We track all of the results from the cognitive testing and training, and we can combine that with demographic information to learn about how people’s cognitive performance changes and develops over the years.”

One such finding, he says, is a correlation between outside weather temperature and cognitive performance: “It turned out that the colder it is, the higher people’s performance is, even though generally they are inside doing this on a computer.”

Most of the scientific projects involving Lumosity’s software are exploring the effectiveness of brain training in different populations, from schoolchildren to stroke patients. For the study on breast cancer survivors, 41 women aged 40 and older, who were at least a year and half past their last chemotherapy treatment, were tested on several cognitive tasks at the beginning of the study. Then half the women used Lumosity training modules for 20 to 30 minutes four times a week for 12 weeks, and all were tested again.

When the investigators tested the participants in verbal memory, processing speed, and cognitive function, they found that the women who had used the brain training program improved in three of five objective measures.

“This is a well-done study—they had not just one transfer test but several,” says Hambrick, who notes that many studies of cognitive training depend on a single test to measure results. “But an issue is the lack of activity within the control group.” Better would be to have the control group do another demanding cognitive task in lieu of Lumosity training—something analogous to a placebo, he says: “The issue is that maybe the improvement in the group that did the cognitive training doesn’t reflect enhancement of basic cognitive processes per se, but could be a motivational phenomenon.”

Even if the effects are due to motivation or some other benefit not related to mental agility, that’s still useful, says Landau. “If [cognitive training] is something that makes people feel good and improves their confidence in their own skills, that’s not trivial at all,” she says. “That could be a big part of the effect that’s observed.”

(Source: technologyreview.com)

Study finds fog-like condition related to chemotherapy’s effect on new brain cells and rhythms.

It’s not unusual for cancer patients being treated with chemotherapy to complain about not being able to think clearly, connect thoughts or concentrate on daily tasks. The complaint – often referred to as chemo-brain – is common. The scientific cause, however, has been difficult to pinpoint.

New research by Rutgers University behavioral neuroscientist Tracey Shors offers new clues for this fog-like condition, medically known as chemotherapy-induced cognitive impairment. In a featured article published in the European Journal of Neuroscience, Shors and her colleagues argue that prolonged chemotherapy decreases the development of new brain cells, a process known as neurogenesis, and disrupts ongoing brain rhythms in the part of the brain responsible for making new memories. Both, she says, are affected by learning and in some cases are necessary for learning to occur.

“One of the things that these brain rhythms do is to connect information across brain regions,” says Shors, Professor II in the Department of Psychology and Center for Collaborative Neuroscience at Rutgers. “We are starting to have a better understanding of how these natural rhythms are used in the process of communication and how they change with experience.”

Working in the Shors laboratory, postdoctoral fellow Miriam S. Nokia from the Department of Psychology at the University of Jyvaskyla in Finland and Rutgers neuroscience graduate student Megan Anderson treated rats with a chemotherapy drug – temozolomide (TMZ) – used on individuals with either malignant brain tumors or skin cancer to stop rapidly dividing cells that have gone out of control and resulted in cancer.

In this study, scientists found that the production of new healthy brain cells treated with the TMZ was reduced in the hippocampus by 34 percent after being caught in the crossfire of the drug’s potency. The cell loss, coupled with the interference in brain rhythms, resulted in the animal being unable to learn difficult tasks.

Shors says the rats had great difficulty learning to associate stimulus events if there was a time gap between the activities but could learn simple task if the stimuli were not separated in time.  Interestingly, she says, the drug did not disrupt the memories that were already present when the treatment began.

For cancer patients undergoing long-term chemotherapy this could mean that although they are able to do simple everyday tasks, they find it difficult to do more complicated activities like processing long strings of numbers, remembering recent conversations, following instructions and setting priorities. Studies indicate that while most cancer patients experience short-term memory loss and disordered thinking, about 15 percent of cancer patients suffer more long-lasting cognitive problems as a result of the chemotherapy treatment.

“Chemotherapy is an especially difficult time as patients are learning how to manage their treatment options while still engaging in and appreciating life. The disruptions in brain rhythms and neurogenesis during treatment may explain some of the cognitive problems that can occur during this time. The good news is that these effects are probably not long-lasting,” says Shors.

(Source: news.rutgers.edu)