Sex-Based Differences in Functional Brain Activity during Working Memory in Survivors of Pediatric Acute Lymphoblastic Leukemia

Characterization of brain development with neuroimaging in a female mouse model of chemotherapy treatment of acute lymphoblastic leukemia

Background

Survivors of pediatric acute lymphoblastic leukemia (ALL) exhibit abnormal neurocognitive outcomes that are possibly due to exposures to neurotoxic chemotherapy agents. This study aimed to determine the feasibility of characterizing long-term neuroanatomical changes with in vivo neuroimaging in a preclinical model of treatment for ALL.

Methods

Female mice (C57BL/6) were randomly assigned to a saline control group (n=10) or a treatment group (n=10) that received intrathecal methotrexate and oral dexamethasone (IT-MTX + DEX). Mice were subsequently scanned three times on a 7T MRI at ages 3, 6, and 12 months (T1, T2, and T3, respectively), which corresponds with human age-equivalents spanning early to late adulthood. Regional brain volumes were automatically segmented, and volume change between timepoints (i.e., T1 to T2; and T2 to T3) were compared between groups (i.e., saline vs. IT-MTX + DEX).

Results

Five mice in the IT-MTX + DEX group, and seven mice in the saline group completed all three scans. Between T1 and T2, volumetric change was significantly different between groups in total gray matter [estimate =2.06, 95% confidence interval (CI): 0.27-3.84], the cerebrum (estimate =1.62, 95% CI: 0.14-3.09), claustrum (estimate =0.06, 95% CI: 0.02-0.09), amygdala (estimate =0.16, 95% CI: 0.03-0.29), and striatum (estimate =0.18, 95% CI: 0.01-0.35), with the IT-MTX + DEX group exhibiting a more robust increase in volume than the saline-treated group. Between T2 and T3, group differences in structural brain development were evident for total white matter (estimate =-0.14, 95% CI: -0.27 to -0.01), and the corpus callosum (estimate =-0.09, 95% CI: -0.19 to 0.00) and amygdala (estimate =-0.05, 95% CI: -0.10 to 0.00). In contrast to the rapid brain growth observed earlier in development (i.e., T1 to T2), the IT-MTX + DEX group exhibited an attenuated increase in volume relative to the saline-treated group between T2 and T3.

Conclusions

The results demonstrate feasibility of modeling pediatric ALL treatment in a preclinical model and highlight the potential of using preclinical neuroimaging models to gain insight into brain development throughout survivorship.

The association of environmental factors with neurocognitive outcomes in survivors of childhood acute lymphoblastic leukemia (ALL)

PURPOSE

To investigate the association of environmental factors, rehabilitation services during therapy and socioeconomic status (SES - insurance type), with neurocognitive outcomes at the end of therapy for survivors of childhood acute lymphoblastic leukemia (ALL).

METHODS

Survivors (n = 236) treated on the St. Jude Total Therapy Study 16 completed end of therapy testing with performance measures (IQ, attention, processing speed, fine motor skills, academics) and caregiver ratings (attention, executive function, adaptive skills). Environmental factors were abstracted from the medical record.

RESULTS

Distribution of sex (47.3% female, p = 0.399), treatment arm (45.5% low risk, 54.5% standard/high risk p = 0.929), insurance type (47.7% private, 52.3% public/none, p = 0.117), and mean age at diagnosis (7.7 vs. 6.8 years, p = 0.143) were similar for groups with (n = 110; 46.6%) and without (n = 126; 53.6%) rehabilitation services during therapy. Compared to those without rehabilitation, the rehabilitation group (n = 110; 46.4%) had more caregiver reported problems with attention (Z = -0.28 vs. 0.43, p = 0.022), executive function (Z = -0.50 vs. -0.08, p = 0.003), and adaptive skills (Z = -0.41 vs.-0.13, p = 0.031). Among the rehabilitation group, there was no difference in outcomes by insurance status. Among those without rehabilitation, those with public insurance had worse neurocognitive outcomes than those with private insurance in IQ (Z = -0.04 vs. -0.45, p = 0.0115), processing speed (Z = -0.10 vs. -0.75, p = 0.0030), reading (Z = 0.18 vs. -0.59, p < 0.0001), and math (Z = -0.04 vs. -0.50, p = 0.0021).

CONCLUSION

Participation in rehabilitation services during early intensive therapy is associated with end of therapy caregiver-reported neurocognitive outcomes in daily life.

Association of markers of inflammation on attention and neurobehavioral outcomes in survivors of childhood acute lymphoblastic leukemia

Background

Survivors of childhood acute lymphoblastic leukemia (ALL) are at-risk of developing cognitive impairment and neurobehavioral symptoms. Inflammation induced by a compromised health status during cancer survivorship is proposed as a pathophysiological mechanism underlying cognitive impairment in cancer survivors.

Objectives

To evaluate the associations of biomarkers of inflammation with attention and neurobehavioral outcomes in survivors of childhood ALL, and to identify clinical factors associated with biomarkers of inflammation in this cohort.

Methods

We recruited patients who were diagnosed with ALL at ≤ 18 years old and were currently ≥5 years post-cancer diagnosis. The study outcomes were attention (Conners Continuous Performance Test) and self-reported behavioral symptoms (Adult Self-Report [ASR] checklist). Using a commercial screening kit, survivors' plasma (5ml) was assayed for 17 cytokines/chemokine cell-signaling molecules that are associated with neurodegenerative diseases. The final panel of the targeted markers included interleukin (IL)-8, IL-13, interferon-gamma (IFN-γ), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1β, and tumor necrosis factor-α. Biomarker levels were rank-ordered into tertiles based on the sample distribution. Multivariable general linear modeling was used to test for associations between biomarkers and study outcomes in the overall cohort and stratified by gender.

Results

This study included 102 survivors (55.9% males, mean[SD] age 26.2[5.9] years; 19.3[7.1] years post-diagnosis). Survivors within top tertiles of IFN-γ (Estimate =6.74, SE=2.26; P=0.0037) and IL-13 (Estimate =5.10, SE=2.27; P=0.027) demonstrated more inattentiveness. Adjusting for age, gender and treatment, more self-reported thought (Estimate=3.53, SE=1.78; P=0.050) and internalizing problems (Estimate =6.52, SE=2.91; P=0.027) correlated with higher IL-8. Higher levels of IL-13 (RR = 4.58, 95% CI: 1.01-11.10) and TNF-α (RR = 1.44, 95% CI: 1.03-4.07) were observed in survivors had developed chronic health conditions (n=26, 25.5%). The stratified analysis showed that association of IFN-γ with attention was stronger in male survivors than in female survivors.

Conclusion

Inflammation due to cancer-related late effects may potentially be mechanistic mediators of neurobehavioral problems in pediatric ALL survivors. Markers of inflammation can potentially be applied to assess or monitor the effectiveness of interventions, particularly behavioral interventions, in improving cognitive outcomes in survivors. Future work includes understanding the underlying gender-specific pathophysiology behind functional outcomes in the population.

[Recent research on cognitive impairment in children with acute lymphoblastic leukemia]

Acute lymphoblastic leukemia (ALL) is the most common malignant neoplastic disease in children. With the continuous improvement in diagnosis and treatment, there has been an increasing number of ALL children who achieve long-term survival after complete remission; however, a considerable proportion of these children have cognitive impairment, which has a serious adverse impact on their learning, employment, and social life. This article reviews the latest research on cognitive impairment in children with ALL from the aspects of the influencing factors, detection techniques, and prevention/treatment methods for cognitive impairment.

Processing efficiency in pediatric cancer survivors: A review and operationalization for outcomes research and clinical utility

OBJECTIVE

Childhood cancer and cancer-related treatments disrupt brain development and maturation, placing survivors at risk for cognitive late effects. Given that assessment tools vary widely across researchers and clinicians, it has been daunting to identify distinct patterns in outcomes across diverse cancer types and to implement systematic neurocognitive screening tools. This review aims to operationalize processing efficiency skill impairment-or inefficient neural processing as measured by working memory and processing speed abilities-as a worthwhile avenue for continued study within the context of childhood cancer.

METHODS

A comprehensive literature review was conducted to examine the existing research on cognitive late effects and biopsychosocial risk factors in order to conceptualize processing efficiency skill trends in childhood cancer survivors.

RESULTS

While a frequently reported pattern of neurobiological (white matter) and cognitive (working memory and processing speed) disruption is consistent with processing efficiency skill impairment, these weaknesses have not yet been fully operationalized in this population. We offer a theoretical model that highlights the impacts of a host of biological and environmental factors on the underlying neurobiological substrates of cancer survivors that precede and may even predict long-term cognitive outcomes and functional abilities following treatment.

CONCLUSION

The unified construct of processing efficiency may be useful in assessing and communicating neurocognitive skills in both outcomes research and clinical practice. Deficits in processing efficiency may serve as a possible indicator of cognitive late effects and functional outcomes due to the unique relationship between processing efficiency skills and neurobiological disruption following cancer treatment. Continued research along these lines is crucial for advancing childhood cancer outcomes research and improving quality of life for survivors.