While helping save or extend the lives of more children with the disease than ever, over 50 percent of pediatric cancer survivors and up to 75 percent of those who undergo the harshest treatments for the illness are impacted cognitively, experts said.
The effects commonly continue for months to years following treatment for pediatric brain tumors, acute lymphoblastic leukemia (ALL), or tumors involving the head and neck.
Each year in the U.S., an estimated 15,780 children between the ages of birth and 19 years of age are diagnosed with cancer, according to the American Childhood Cancer Organization. Globally, more than 300,000 children are diagnosed with cancer each year. ALL and non-Hodgkin lymphoma account for 30 percent of childhood cancers (J Natl Cancer Inst 2017; doi:10.1093/jnci/djw321). Prophylactic cranial irradiation has been shown to prevent relapse and increase survival, but the possibility of late neurocognitive sequelae remains a concern, the study said.
Additionally, young adults who underwent chemo for leukemia or lymphoma as children showed decreased cognitive flexibility and weaker short-term memory, according to a small Belgium study (J Natl Cancer Inst 2017; doi:10.1093/jnci/djw321). Researchers linked the decreases to levels of a specific protein in the brain fluid—phosphorylated Tau. Ability to concentrate and long-term memory appeared unaffected by chemo.
The study also showed that adult childhood leukemia and lymphoma survivors displayed statistically significant lower total (p=.001), verbal (p=.02), and performance (p=.007) IQs than controls, although results remained within the range of normality.
Medical specialists continue to drill down on the needs of parents of children with cancer, along with schools, to abet the ability of youngsters to reach their academic potential despite the effects of treatment on their cognitive skills. That's especially so as the survival rate for childhood cancers climb—from 4 percent more than 50 years ago to about 94 percent today for the most common childhood cancer (ALL), according to Heather Conklin, PhD, Associate Member of the Department of Psychology and Chief of the Neuropsychology Section at St. Jude Children's Research Hospital.
“As we saw that shift in survival rates, people like me got involved in the field to better understand the types of problems survivors were experiencing, and then figure out how to develop interventions to help them,” said Conklin, who studies a variety of issues surrounding cognitive functioning for pediatric cancer patients.
Tracking the progress of children over time using global measures of cognition, such as IQ, helped medical experts confirm that youngsters were declining cognitively, she continued. That trend sometimes confused parents since, simultaneously, their children gained new skills, albeit at a slower rate than their healthy peers.
“We weren't sure why, so we peeled back the layers to get a better handle on the specific underlying cognitive difficulties,” said Conklin. They discovered kids were having problems most notably in three areas of learning: focused attention, the ability to process information efficiently, and working memory, a part of short-term memory that can help with activities such as performing mental computations for math.
Risk factors for cancer-related cognitive dysfunction include young age at diagnosis, treatment with cranial irradiation, use of parenteral or intrathecal methotrexate, female sex, and pre-existing comorbidities (J Natl Cancer Inst 2014; doi.org/10.1093/jnci/dju186). Limiting use and reducing doses and volume of cranial irradiation while intensifying chemotherapy have improved survival and reduced the severity of cognitive dysfunction, especially in leukemia.
Nonetheless, problems in core functional domains of attention, processing speed, working memory, and visual-motor integration continue to compromise quality of life and performance.
Wengenroth and colleagues from Swiss Paediatric Oncology Group studied data from 840 survivors and reported statistically significant problems with concentration, slow working speed, and memory compared to the siblings of the affected children, according to Max Brzezicki, BMedSc (1st Hons) FNS, President of the Oxford Neurological Society and Clinical Research Fellow, Nuffield Department of Clinical Neurosciences, University of Oxford. U.K. (Pediatr Blood Cancer 2015;62(5):875-882).
A similar study by Margelisch et al. showed significant discrepancies in working memory, verbal memory, and attention (Pediatr Blood Cancer 2015;62(10):1805-1812).
In addition, describing it as a challenging space, Lisa Jacobson, PhD, ABPP, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, said that, as a neuropsychologist, she works with survivors and their families around how to pinpoint an individual child's strengths and needs, and the types of support that would help them.
That's the impetus for a project called “Surviving Cancer, Thriving in Life,” which involves surveying survivors and families to identify current resources and where more information and support are needed to address unmet needs. “The project arose from hearing families repeatedly say how difficult it is to get the kinds of interventions and support that their children need,” said Jacobson, principal investigator of the project.
Conklin recalls when “parents felt blindsided” upon learning of their child's cognitive difficulties stemming from treatment because they were so focused initially on a cure. Now, parents have become educated consumers and want to discuss various methods upfront to help mitigate those cognitive late effects.
However, schools remain at least slightly behind the eight ball, she continued. That's primarily because, “thankfully, cancer's a rare diagnosis in childhood, so a particular teacher or school will only infrequently face this situation.” Consequently, some of their work is devising ways to educate teachers and developing models in which hospitals have a staff member dedicated to serving as a liaison between the medical team and school.
While schools are eager to provide support for the child who's experienced a cancer diagnosis, they're often unfamiliar with the kinds of needs those students may have and are sometimes anxious about how to go about managing the academic needs of those children, according to Kathryn Kirkpatrick, PhD, LISW-S, Education Coordinator, Hematology/Oncology/BMT, at Nationwide Children's Hospital in Columbus, Ohio. “Once the schools are educated about the cognitive late effects such as attention, memory, and processing delays, they are then generally equipped to manage those concerns.”
She also noted that helping parents and schools understand how to recognize and address cognitive late effects of cancer and related treatment can be complicated by the fact that the cognitive impacts are often invisible. Families and school personnel are thankful to see a “well child” return to the classroom.
Jacobson said one thing that would help is educational specialists, who could serve as a liaison between schools and hospitals, “such as those who can translate medical information to schools and help integrate the information into clinics. When we have someone available within the hospital setting who can connect with families and help them learn the vocabulary and process of how to work with the school team, children are more likely to have better outcomes.”
Yet, in their systematic review, Baumann et al. reported that “child-specific aspects such as cognitive abilities, growth, adolescence, and reintegration into peer groups, school, and sports have barely been taken into consideration” in the studies they have assessed (Pediatric Research 2013;74:366-374).
Whatever the case, another consideration: at least some parents often don't know how hard to push a child to continue doing schoolwork during treatment, added Kirkpatrick. If a child has little instruction during the course of treatment (so they can focus on their health), any cognitive late effects will be magnified by the missed instruction.
Families want to be hopeful that their child will not be one to suffer cognitive impact, so they sometimes delay assessment in the interest of giving the child a chance to catch up and settle in to the routine of school once again, she continued.
Aside from the educational component, studies in pediatric oncology have shown a positive effect of physical activity on disease- and treatment-related side effects (Pediatric Research 2013;74:366-374).
Separately, to help survivors, St. Jude is developing several interventions, including finding medicine to help ameliorate late effects of cancer therapy. “A lot of our research investigates stimulant medication that had more historically been used in kids with attention deficit disorder. Our cancer survivors tolerate it well in terms of side effects, and show improved attention and social skills,” said Conklin.
But medication isn't appropriate for every situation, she noted. “A number of our parents feel like their child has already been through a lot and don't want to introduce a stimulant medication.” In those cases, St. Jude staff members have introduced cognitive rehabilitation, where patients work one on one with a therapist, who teaches new strategies for approaching problems like breaking a problem down into steps. Families have shown interest in those kinds of interventions and they're particularly good for improving scholastic skills.
However, not all survivors live near a center where they can get that kind of service and they can be expensive, time-consuming and not as easy as taking a pill. With that in mind, a great deal of research is now being performed with computerized cognitive training, Conklin explained.
Currently, St. Jude's conducts extensive research with computerized cognitive training. It allows the hospital to monitor the progress of its survivors, who all over the world, through the internet, noted Conklin. “We can talk to them weekly, coach them, help maintain their motivation, and provide strategies.”
Chuck Green is a contributing writer.