Epidemiology and etiology of brain cancer in Africa: A systematic review.

BACKGROUND: Cancer is a significant threat to public health and a leading cause of morbidity across the globe. Of all cancers, brain cancer can be particularly catastrophic as treatment often fails to achieve the desired degree of effectiveness and diagnosis remains associated with a high mortality rate. Africa, as a continent with resource-limited countries, needs to allocate the necessary proper healthcare infrastructure to significantly reduce cancer rates and improve patient survival. In addition, the relative paucity of data within this field in Africa makes effective management a challenge. OBJECTIVE: This review is aimed at elucidating the currently available evidence base with regard to the epidemiology and etiology of brain cancer within resource-limited African countries. This review hopes to bring to the attention of the wider clinical community the growing burden of brain cancer within Africa and to encourage future research into this field of research. METHODS: The available literature for this Systematic Review was searched on two bibliographic databases, PubMed and Scopus, using an individually verified, prespecified approach. In addition, the Global Cancer Observatory and Global Burden of Disease databases were also utilized. Studies reporting on the epidemiology, etiology, and impact of brain cancer in Africa were suitable for inclusion. The level of evidence of the included studies was considered as per the Centre for Evidence-Based Medicine recommendations. RESULTS: Out of the four databases searched, 3848 articles were initially screened rigorously, filtered into 54 articles, and finally assessed qualitatively and quantitatively. We have demonstrated a poor survival rate and lack of proper funds/resources necessary to report, identify, and treat cases, as well as the dearth of comprehensive research on the subject of brain cancer that has become a challenging healthcare concern in many African developing nations. Also, because of the gradual improvement in healthcare facilities and the increasing population within many countries in Africa, the number of patients with central nervous system and intracranial tumors is rising specifically in the elder population. In addition, the population in West Africa is at a higher risk of HIV-related malignancies due to the high prevalence of HIV in West Africa. The burden of brain cancer in Africa is increasing in comparison with the developed parts of the world in which it is decreasing. Moreover, the mismanagement of cancers in Africa leads to higher morbidity and mortality and decreased quality of life. CONCLUSION: This study addresses the burden of brain cancer as a major public health crisis in Africa. Improved treatment modalities and access to screening are required to better address the burden of this disease. Therefore, there is a clear need for more substantial and comprehensive research on etiology, epidemiology, and treatment of brain cancer within Africa to understand its epidemiological distribution and provide a means for managing and reducing the associated morbidity and mortality.

Prevalence Estimates of Amyloid Abnormality Across the Alzheimer Disease Clinical Spectrum.

IMPORTANCE: One characteristic histopathological event in Alzheimer disease (AD) is cerebral amyloid aggregation, which can be detected by biomarkers in cerebrospinal fluid (CSF) and on positron emission tomography (PET) scans. Prevalence estimates of amyloid pathology are important for health care planning and clinical trial design. OBJECTIVE: To estimate the prevalence of amyloid abnormality in persons with normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia and to examine the potential implications of cutoff methods, biomarker modality (CSF or PET), age, sex, APOE genotype, educational level, geographical region, and dementia severity for these estimates. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional, individual-participant pooled study included participants from 85 Amyloid Biomarker Study cohorts. Data collection was performed from January 1, 2013, to December 31, 2020. Participants had normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia. Normal cognition and subjective cognitive decline were defined by normal scores on cognitive tests, with the presence of cognitive complaints defining subjective cognitive decline. Mild cognitive impairment and clinical AD dementia were diagnosed according to published criteria. EXPOSURES: Alzheimer disease biomarkers detected on PET or in CSF. MAIN OUTCOMES AND MEASURES: Amyloid measurements were dichotomized as normal or abnormal using cohort-provided cutoffs for CSF or PET or by visual reading for PET. Adjusted data-driven cutoffs for abnormal amyloid were calculated using gaussian mixture modeling. Prevalence of amyloid abnormality was estimated according to age, sex, cognitive status, biomarker modality, APOE carrier status, educational level, geographical location, and dementia severity using generalized estimating equations. RESULTS: Among the 19 097 participants (mean [SD] age, 69.1 [9.8] years; 10 148 women [53.1%]) included, 10 139 (53.1%) underwent an amyloid PET scan and 8958 (46.9%) had an amyloid CSF measurement. Using cohort-provided cutoffs, amyloid abnormality prevalences were similar to 2015 estimates for individuals without dementia and were similar across PET- and CSF-based estimates (24%; 95% CI, 21%-28%) in participants with normal cognition, 27% (95% CI, 21%-33%) in participants with subjective cognitive decline, and 51% (95% CI, 46%-56%) in participants with mild cognitive impairment, whereas for clinical AD dementia the estimates were higher for PET than CSF (87% vs 79%; mean difference, 8%; 95% CI, 0%-16%; P = .04). Gaussian mixture modeling-based cutoffs for amyloid measures on PET scans were similar to cohort-provided cutoffs and were not adjusted. Adjusted CSF cutoffs resulted in a 10% higher amyloid abnormality prevalence than PET-based estimates in persons with normal cognition (mean difference, 9%; 95% CI, 3%-15%; P = .004), subjective cognitive decline (9%; 95% CI, 3%-15%; P = .005), and mild cognitive impairment (10%; 95% CI, 3%-17%; P = .004), whereas the estimates were comparable in persons with clinical AD dementia (mean difference, 4%; 95% CI, -2% to 9%; P = .18). CONCLUSIONS AND RELEVANCE: This study found that CSF-based estimates using adjusted data-driven cutoffs were up to 10% higher than PET-based estimates in people without dementia, whereas the results were similar among people with dementia. This finding suggests that preclinical and prodromal AD may be more prevalent than previously estimated, which has important implications for clinical trial recruitment strategies and health care planning policies.

[Diagnosis and treatment of normal pressure hydrocephalus].

This review summarises the current knowledge of normal pressure hydrocephalus (NPH), which is considered to be a reversible cause of dementia. Early identification is important to select patients for surgical treatment with ventricular shunting. The symptoms of NPH are gait disturbance, cognitive dysfunction and urinary incontinence. NPH is diagnosed by a combination of the clinical presentation and neuroimaging and preferably supported by cerebrospinal fluid tests. The pathophysiology is not well described and a significant overlap with degenerative and small vessel brain diseases exist, making selection of patients for surgery difficult.