Intracranial gliomas in Ferrara, Italy, 1976 to 1991

The global prevalence of primary central nervous system tumors: a systematic review and meta-analysis

BACKGROUND

Primary central nervous system (CNS) tumors are a heterogeneous group of neoplasms, including benign and malignant tumors. Since there are many heterogeneities in the prevalence reported in previous studies on this type of tumor, this study was performed to determine the overall prevalence of different primary CNS tumors.

METHOD

The study was conducted as a systematic review and meta-analysis by searching international databases, including PubMed, Scopus, Science Direct, Web of science, and the Google Scholar search engine until August 2020. After transferring the studies to information management software (EndNote) and eliminating duplicate studies, the remaining studies were reviewed based on inclusion and exclusion criteria according to three stages of primary and secondary evaluation and qualitative evaluation. Comprehensive Meta-Analysis software, Begg, Mazumdar, and I² tests were used for data analysis, publication bias analysis, and heterogeneity analysis, respectively.

RESULTS

After performing the systematic review steps, 80 studies were included for final analysis. Based on 8 studies, the prevalence of brain tumors was 70.9%. Also, studies on 7 other studies showed that the prevalence of spinal tumors was 12.2%. A review of 14 studies showed that the prevalence of neuroepithelial tumors was 34.7%. The analysis of 27 studies reported a prevalence of glioma tumors of 42.8%. Analyses performed on other studies showed that the prevalence of pituitary adenomas was 12.2%, embryonal tumors 3.1%, ependymal tumors 3.2%, meningiomas 24.1%, glial tumors 0.8%, astrocytic 20.3%, oligodendroglial 3.9%, glioblastoma 17.7%, schwannoma 6.7%, medulloblastoma 7.7% and Polycystic astrocytomas 3.8%.

CONCLUSION

As a result, it can be stated that brain tumors are the most common type of primary CNS tumors. It was also observed that tumors involving neuroepithelial cells are more common in patients than other types of tumors.

Circular RNA circMAN2B2 facilitates glioma progression by regulating the miR-1205/S100A8 axis

The aim of this study was to research the mechanism of circMAN2B2 in the development of glioma. In our study, we found that circMAN2B2 has a higher expression in glioma tissues and cells, which was negatively related to the overall survival of glioma patients. The cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine labeling assay, transwell assay, and the nude mice assay indicated that knockdown of circMAN2B2 inhibited the cell proliferation, invasion, migration and decreased tumor size. In terms of mechanism, knockdown of circMAN2B2 increased the expression of miR-1205. Moreover, circMAN2B2 regulated S100A8 expression by inhibiting miR-1205. We also showed that knockdown of S100A8 inhibited cell proliferation, invasion, and migration. Increasing S100A8 expression rescued the effect of si-circMAN2B2. In conclusion, circMAN2B2 could improve cell proliferation, invasion, and migration of the glioma by inhibiting miR-1205 and promoting the expression of S100A8.

Low Grade Gliomas in Children

Gliomas represent the most common solid tumor of the nervous system, and can occur as both low and high-grade tumors. Current risk stratification and treatment approaches rely heavily on the morphological classification of gliomas whereby low-grade gliomas have an excellent prognosis, particularly pilocytic astrocytomas, while high-grade gliomas have a poor prognosis. The past decade has witnessed a dramatic increase in scholars' knowledge of the biology of pediatric low-grade gliomas particularly through the advent of integrated genomics and next generation sequencing. Indeed, many of these biological advances are changing treatment paradigms, particularly in low-grade gliomas, where rationale targeted therapies are currently being explored in clinical trials. In this review the authors summarize the current approach to pediatric low grade gliomas and outline the biological advances over the past 10 years, which will be driving the next generation of clinical trials.

Incidence of and survival from oligodendroglioma in Denmark, 1943-2002

We established the nationwide, population-based incidence of oligodendroglioma in Denmark during 59 years of monitoring and compared the overall survival of patients with oligodendroglial tumors during the periods 1943-1977 and 1978-2002. On the basis of reports in the Danish Cancer Registry, 1,304 cases of oligodendroglioma were included in the study. We calculated sex- and age-specific incidence rates in 5-year age intervals and for 5-year calendar periods. Overall survival was estimated by the Kaplan-Meier method. In the period 1943-2002, the incidence rate of oligodendroglioma was less than 1 case per 100,000 person-years, but varied somewhat when viewed across isolated periods. Comparison of the incidence rate before and after the introduction of CT scanning did not reveal a significant difference in the incidence rate. The median survival increased from 1.4 years (95% confidence interval [CI], 1.0-1.6) to 3.4 years (95% CI, 2.6-4.2) during the period of study. The overall incidence of oligodendroglioma showed a relatively stable pattern over nearly 60 years of monitoring. Overall survival improved significantly during the study period, which could partly be due to improved diagnostic methods and treatment options.

Immunohistochemical evaluation of the microvascular density through the expression of TGF-beta (CD 105/endoglin) and CD 34 receptors and expression of the vascular endothelial growth factor (VEGF) in oligodendrogliomas

Angiogenesis has been proposed as essential for the growth of solid tumors. The determinants of this process, the growth factors and the vascular endothelial receptors have brought a potential in the tumor prognostic determination as well as perspectives of "targets" for antiangiogenic therapy. In oligodendrogliomas (OL), angiogenesis is little known and/or has generated conflicting results. In order to clarify angiogenesis in OL, we have evaluated the immunohistochemical expression of vascular endothelial growth factor (VEGF) and the microvascular density (MVD) through the expression of TGF-beta (CD105/endoglin) (MVD-CD105) and CD34 (MVD-CD34) receptors using the Chalkley point method in 30 OL. No significant immune reaction was found for the VEGF. There was expression in <10% of tumor cells and/or staining of weak intensity in 15 (50.0%), >10% of cells and moderate intensity staining in 1 (3.33%), and negative expression in 14 (46.67%). If present, the expression was restricted to tumor and endothelial cells. Our findings suggest that VEGF has little influence on OL angiogenesis. All specimens showed CD105 and CD34 expression in the intratumor vascular endothelium, suggesting involvement of CD105 in OL angiogenesis. The mean +/- SD MVD-CD105 and MVD-CD34 were 10.83 +/- 2.24 and 11.00 +/- 2.76 in OL (P = 0.086; r = 0.319); 10.00 +/- 2.00 and 10.40 +/- 3.02 in OL grade II (n = 15) (P = 0.547; r = 0.105), and 11.67 +/- 2.22 and 11.53 +/- 2.45 in OL grade III (n = 15) (P = 0.817; r = 0.551), respectively. The absence of correlation between DMV-CD105, DMV-CD34 and tumor grades suggests that anti-CD105 and anti-CD34 antibodies have different vascular specificities. MVD-CD105 was greater in OL grade III than in OL grade II (P = 0.0032), indicating an increase in the vascular neoformation, something which must be evaluated as a possible prognostic factor in OL. Both TGF-beta and CD105 bring perspectives as "targets" for antiangiogenic treatments in OL.

Incidence of gliomas by anatomic location

The anatomic location of a glioma influences prognosis and treatment options. The aim of our study was to describe the distribution of gliomas in different anatomic areas of the brain. A representative population-based sample of 331 adults with glioma was used for preliminary analyses. The anatomic locations for 89 patients from a single center were analyzed in more detail from radiologic imaging and recorded on a three-dimensional 1 x 1 x 1-cm grid. The age-standardized incidence rate of gliomas was 4.7 per 100,000 person-years. The most frequent subtypes were glioblastoma (47%) and grade II-III astrocytoma (23%), followed by oligodendroglioma and mixed glioma. The gliomas were located in the frontal lobe in 40% of the cases, temporal in 29%, parietal in 14%, and occipital lobe in 3%, with 14% in the deeper structures. The difference in distribution between lobes remained after adjustment for their tissue volume: the tumor:volume ratio was 4.5 for frontal, 4.8 for temporal, and 2.3 for parietal relative to the occipital lobe. The area with the densest occurrence was the anterior subcortical brain. Statistically significant spatial clustering was found in the three-dimensional analysis. No differences in location were found among glioblastoma, diffuse astrocytoma, and oligodendroglioma. Our results demonstrate considerable heterogeneity in the anatomic distribution of gliomas within the brain.

Incidence of brain tumours in two English counties: a population based study

OBJECTIVE

To define the incidence of brain tumours in Devon and Cornwall and to discover which case finding methods are the most fruitful. To examine what happens to patients after the diagnosis of a brain tumour.

METHODS

The primary method of case ascertainment was a review of all CT with contrast and MRI of the head performed on the population of Devon and Cornwall between 1 April 1992 and 31 March 1997. Secondary sources included registrations with the South and West Cancer Intelligence Unit and a search for all patients either admitted to hospital with a brain tumour or operated on for a brain tumour during the same period.

RESULTS

16,923 scans were reviewed of which 8774 (52%) were normal. The scan review found 2483 incident intracranial tumours, of which 861 were metastases. Secondary sources of case ascertainment disclosed 46 further cases. Cases were missed by the scan review mainly for technical reasons and only three patients were found who were diagnosed by non-imaging methods. The incidence of primary intracranial tumours standardised to the population of England and Wales was higher than any previously reported (21.04 (17.18-25.62)/100,000 person-years). Overall, 21% of cases were not admitted to hospital. The categories least likely to be admitted were those with sellar and cranial nerve tumours. Those not admitted to hospital were significantly older than those who were.

CONCLUSION

One fifth of patients are not admitted to hospital after the diagnosis of a brain tumour and incidence studies must use case finding methods which will capture these cases. An audit of imaging results provides almost complete case ascertainment. This study shows that the incidence of primary brain tumours is considerably higher than previously thought. Official figures from the cancer intelligence units significantly underestimate brain tumour incidence, especially for benign tumours.

Brain cancer incidence in the provinces of Zaragoza and Navarre (Spain): effect of age, period and birth cohort

Several studies have detected increases in malignant brain tumour incidence and mortality rates particularly among the elderly. We analyzed time trends in malignant brain tumors incidence in Zaragoza over the period 1973-1990 and Navarre over the period 1973-1991, two Spanish provinces that have been collecting data through their respective Cancer Registries for the last 20 years, using Poisson regression analysis of age, period of diagnosis and cohort. In general, age-adjusted rates showed a steady rise in both registries, except in the case of females in Navarre, for whom a decrease in risk was observed for the last period, 1988-1991. This increase is a reflection of the rise in incidence experienced by the elderly, since the cohorts successively register rates that are stable over time, and even downward in the case of females in Navarre. The risk run by generations born circa 1920-1930 was the highest encountered. Rates were higher in Navarre in both sexes and for all but the last period in females, when rates on the two registers stood level. Increasingly generalised use of CT scanning and magnetic resonance in the 1980s in Spain, coupled with better and more effective health care access for the elderly, are factors that may well have some bearing on these findings.