Neurocognitive status in long term survivors of childhood CNS malignancies
This paper explores a published report from the childhood cancer survival study on a research conducted on the neurocognitive status in long term survivors of childhood central nervous (CNS) system malignances. The research was conducted by comparing a group of survivors of CNS malignances to a group of non CNS malignances survivors and their siblings who have no cancer. Approximately 14,363 survivors and 3899 siblings participated in the research. Data was collected from the participants using an instrument developed based on behavior rating inventory of executive functioning (BRIEF) Four main factors were considered, they included emotional regulation, task efficiency memory and organization. The aim of the research was to determine; if survivors of CNS malignancies would report greater neurocognitive disorders compared to the non CNS survivors and there siblings, where the greatest neurocognitive disorders would occur and if the neurocognitive impairment would be associated with poor adaptive outcome in adulthood.
Neurocognitive status in long term survivors of childhood CNS malignancies
Some of the most common solid malignancies in childhood are the Cancers of the central nervous system (CNS). They are usually associated with dysfunctions that occur in various parts of the body some of this includes the neurologic and neurocognitive areas.(Anderson et al,2001)In the neurocognitive areas a number of deficits have been reported in functions such as memory, attention, verbal skills, Intelligence quotient (IQ) and learning. Recent research in particular has been focused on working memory, processing speed and attention as the main areas that show dysfunction especially to survivors of cancer of the CNS at childhood. Within the pediatric patients with CNS Malignancies, there are some factors that have been associated with neurocognitive outcome. They include the age at diagnosis, the site of the tumor and the radiation treatment.(Ris,2005)
In the case of site of the tumor, Cortical and pediatric posterior fossa tumors have been associated with deficits in executing functions, memory planning and attention. On the other hand Radiation treatment such as prophylactic cranial radiation causes changes including calcification and reduction in the white matter yet most cognitive factors are very sensitive to any form of damage to the white matter. In matters of age Patients of younger ages especially those below the age of eight who undergo radiation treatment tend to show great neurocognitive impairment in areas like nonverbal abstract thinking IQ and knowledge compared to older patients. In order to confirm these facts a research was conducted. ( Karatekin et al.,2000;Levinsohn et al., 2000)
The main aim of the research was to examine and quantify neurocognitive functioning and adaptive outcome in adult survivors of childhood CNS malignances between the ages of 16-34 from their original diagnosis. A large group of CCSS were evaluated CNS malignancy survivors were enrolled to determine their degree of reported neurocognitive dysfunction compared to survivors of non CNS malignancy and also their siblings. Factors related to treatment like cranial radiation, illnesses and demographic variables like gender and age at diagnosis that might be associated with greater neurocognitive dysfunctions were accessed among the CNS malignancy survivors. They laid down hypotheses that; The survivors of CNS malignances would report more neurocognitive dysfunctions than non CNS malignances and siblings, The most reported neurocognitive dysfunctions would be processing speed, memory, and planning and organization aspects of task efficiency an executive functioning, That there would be more reported neurocognitive dysfunctions in CNS malignancy survivors who had significant motor or sensory residuals, cranial radiation, and cortical tumors or were younger at diagnosis and finally that neurocognitive impairment would be related to poorer adaptive outcome in adulthood(Ellenberg et al. ,2009)
Methods and Procedures used
The researcher’s conducted the research on a large group of individuals using various instruments to collect and analyze the data obtained both from the participants. They managed to come up with conclusive results that proved many of the hypotheses they had stated before embarking on this study research.
The main participants of this research included a group of children who have been treated for cancer at 26 collaborating institutions in the United States and in Canada referred to as the CCSS and all patients below the age of 21 who had survived for over five years that had been diagnosed with leukemia, CNS malignancy, Hodgkin’s disease, non Hodgkin’s lymphoma, kidney cancer, neuroblastoma, soft tissue sarcoma or malignant bone tumor between the years of 1970 and 1985. They managed to enroll 14,363 survivors and 3899 siblings. There Also was a follow up survey in 2003 where 9308 survivors and 2951 siblings participated. The childhood cancer survivor study neurocognitive Questionnaires (CCSS-NCQ) was included in the follow up survey. (Ellenberg et al. ,2009)
In order for The researchers to assess self reported neurocognitive functioning , they developed an instrument based on the behavior rating inventory of the executive functioning (BRIEF), a multidimensional standardized behavior rating inventory for children, adolescents and adults with scales that were labeled inhibit, shift, emotional control, initiate, working memory, plan/organize, organization of materials and monitor. The researcher’s combined two items of each BRIEF that had the highest item total correlation with independently derived items designed to asses the neurocognitive areas of processing speed, memory and academic functioning. This enabled them to come up with four valid and reliable factors namely Task efficiency, emotional regulation, organization and memory.(Ellenberge et al. ,2009)
Treatment and Radiation Exposure
The researcher’s obtained medical records for treatment related information that included chemotherapy, surgery and radiation therapy. In order for them to quantify radiation exposure they partitioned the brain into four segments, the posterior fossa, temporal lobe, frontal cortex and the parietal or occipital lobe. The maximum radiation dosages were assigned for each field by utilizing radiation oncology records from the treating institutions.
The researchers analyzed the data they had obtained from the participants by generating descriptive statistics for gender, ethnicity, age, employment status, education, and household income. They compared the groups on each of the four CCSS-NCQ factor scores via multiple linear regression making adjustments for age at the time of study, gender and ethnicity.
When they were comparing the survivors and siblings they modified the linear regression by using generalized estimating equations and used it to account for potential with-in-family correlation. They further analyzed the only survivors of CNS malignancy using multiple linear regressions to asses the effects of potential independent variables.
When assessing the contributions of more specific factors to outcome for individual comparisons, they adjusted for age at the time of the study, gender and ethnicity in the multiple linear regressions.
When assessing the effect of tumor site in radiated CNS malignancy survivors, they compared those with cortical versus subcortical radiation boosts.
When assessing the effect of radiation dose on neurocognitive outcome, they compared CNS malignancy survivors who received cortical radiation without a cortical tumor to leukemia survivors who received 24 Gy of cranial radiation and non-irradiated leukemia patients.
Finally when assessing the relationship between neurocognitive outcome and socioeconomic variables in adulthood they used individual multiple linear regressions to examine the association between age, gender and ethnicity adjusted CCSS-NCQ scores of CNS malignancy survivors and educational attainment. From the analysis they performed they came out with conclusive results to verify and further support the hypothesis earlier stated. .(Ellenberg et al.,2009)
The researchers made a number of conclusions. On the effects of neurocognitive impairment to outcome in adulthood, they noted that the sibling group was more likely to grow older, become more educated, be more likely to be employed, earned more and were much more likely to be married compared to the CNS and non CNS survivors. Also the CNS survivors were more likely to be male; less educated and earned less than non-CNS survivors. They were also more probable to have received surgery but not chemotherapy compared to non CNS survivors.
On the question of Neurocognitive outcomes, they concluded that CNS malignancy survivors reported significantly greater neurocognitive dysfunction than the sibling group and non CNS malignancy survivors on all CCSS-NCQ factors. Specifically on organization and emotional regulation effect sizes for the difference between the all the groups were small for memory it was medium and large for task efficiency.
Finally another very important conclusion they made was that medical complications such as visual and hearing difficulties paralysis and stroke were associated with greater reported deficits on all of the CCSS-NCQ factors with generally small effect sizes. Cranial radiation was correlated with greater impairment on task efficiency and memory with medium effect sizes for total brain irradiation and smaller effect sizes for total brain irradiation and smaller effect sizes for partial brain irradiation.
The research that was conducted on the neurocognitive status of survivors of CNS malignancies was successful. The number of participants used was satisfactory it represented a significant number of the patients with this condition. The researchers were qualified and were able to show that neurocognitive dysfunctions occurred mostly to survivors of CNS malignancies and also showed the effects of neurocognitive impairment to the lives of adult patients on issues of employment payments educational achievements and marriage.
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