Early Neurocognitive Outcome Post Resection of Adult Supratentorial Gliomas at the Kenyatta National Hospital

Abstract

Introduction: Gliomas are among the commonest primary brain tumors in our setting. Despite significant advances in molecular diagnosis and elucidation of pathogenesis, the prognosis remains poor especially for High grade gliomas. Maximal safe resection is the first step in the multimodal management of gliomas. However, surgical resection is limited by the lack of a clearly defined brain-tumor interface which is due to tumoral infiltration beyond the radiologically defined boundaries. Traditionally, Overall Survival, progression free survival and Extent of resection are used to define oncologic outcome in gliomas. Oncologic outcome however, does not reflect the complete patient status and hence the need for functional outcome determination. Cognitive outcome which is a key functional outcome measure in gliomas is the subject of this study. Study Design: Prospective Cohort Study. Broad Objective: To determine the Early Neurocognitive outcome post resection of adult supratentorial gliomas at the KNH. (Kenyatta National Hospital) Study area: Neurosurgery Unit at the KNH. (Kenyatta National Hospital) Study Population: Adult patients with supratentorial gliomas presenting to KNH. (Kenyatta National Hospital) Sample size: We examined twenty patients (20) with supratentorial gliomas who met the inclusion criteria. Data collection: An interviewer based questionnaire incorporating the ACE III (Addenbrooke Cognitive Examination III ) Cognitive Assessment tool was administered at three instances as follows:- Within two weeks Preoperatively (T0), at one week postoperatively (T1) and at four weeks postoperatively (T2). Data Analysis: Statistical Package for Social Sciences version 23.0 software was used for analysis. The pre and post operative cognitive scores were then analyzed to determine the cognitive outcome and presented as frequencies and proportions for categorical data or as means with standard deviations for continuous data. The overall and domain specific early 15 | P a g e cognitive scores were analyzed and presented as frequencies, proportions and means with standard deviation. The relationship between cognitive outcome and extent of resection as well as that of the histologic subtype was assessed with the use of Fisher's Exact test. Statistical significance was considered where the p-value was <0.05. Results :- Ninety five percent (95 %) of patients had cognitive impairment at baseline. Mean age of presentation was 34.3 years for LGG (Low grade glioma) and 43.8 years for HGG (High Grade Glioma). 55% of patients had LGG while 45% had HGG. Overall, there was transient decline in cognition from T0-T1 and a gradual improvement beyond the baseline from T1-T2. This improvement was across all domains but was significant in the total ACE score (P- value 0.025), memory (P -value 0.008) and fluency (P -value 0.001). LGG showed the greatest improvement in cognition especially in the fluency domain (P- value 0.030). Sixty percent (60 % )of the tumors were subtotally resected while 40 % were grossly resected. The subtotally resected tumors showed significant cognitive change in the domains of Attention (P-value 0.029), fluency (P-value 0.045) and Visuospatial association (P-value 0.017). Grossly resected tumors had a significant cognitive change in memory (P- value 0.046) and fluency (P- values 0.024). Conclusion: Surgery for supratentorial gliomas results in a transient decline in cognition one week postoperatively after which significant improvement in cognition beyond the baseline is noted one month post operatively. The transient decline is likely due to the effects of surgery on the tumor bed and the subcortical circuits while the improvement is likely due to enhanced plasticity and reduction in mass effect from the tumor. LGG have the most significant improvement in cognition especially in the domains of memory and fluency. Extent of resection and histologic subtype likely have no significant effect on the change in total ACE III cognitive scores at one month postoperatively.