Medical history, cigarette smoking and risk of acoustic neuroma: an international case-control study

[Vestibular Schwannoma: Factors in Therapy Decision-Making]

The treatment of vestibular schwannomas (VS) has always posed a challenge for physicians. Three essential treatment principles are available: wait-and-scan, surgery, and stereotactic radiotherapy. In addition to the type of treatment, decisions must be made regarding the optimal timing of therapy, the combination of different treatment modalities, the potential surgical approach, and the type and intensity of radiation. Factors influencing the therapy decision include tumor location and size or stage, patient age, comorbidities, symptoms, postoperative hearing rehabilitation options, patient preferences, and, not least, the experience of the surgeons and the personnel and technical capabilities of the clinical site. This article begins with a brief overview of vestibular schwannomas, then outlines the fundamental interdisciplinary treatment options, and finally discusses the ENT (ear, nose, and throat)-relevant factors in the therapy decision.

Large vestibular schwannomas presenting in the late state of pregnancy: a case report and literature review

Vestibular schwannomas in pregnancy have rarely been reported, and there is a lack of in-depth discussion on the experience of management of massive acoustic neuromas in pregnancy. Herein, we present a pregnant woman with a giant vestibular schwannoma and obstructive hydrocephalus who presented at 30 weeks of gestation. She was initially misdiagnosed as having a pregnancy-related reaction of headache, dizziness, and vomiting that had occurred 2 months earlier. After observation at home, her symptoms progressed at 30 weeks of gestation, and imaging findings revealed a brain tumor in the CPA region with secondary cerebella tonsil herniation and obstructive hydrocephalus, and she was transferred to our center for treatment. Consequently, we relieved her hydrocephalus with a ventriculoperitoneal shunt (V-P shunt) and used corticosteroids to simulate fetal maturation. After 10 days, her mental condition deteriorated, and her right limb muscle strength gradually decreased until grade 0 (MMT Grading). Finally, under a joint consultation with the Department of Neurosurgery, Obstetrics, and Anesthesiology, she underwent a cesarean section under general anesthesia and first-stage tumor removal at 31 weeks of gestation. Upon discharge, the previously observed neurological deficits, which were reversible and had manifested during her gestational period, had been successfully resolved, and the fetus had been conserved. The neuroimaging confirmed the complete tumor removal, while the neuropathologic examination revealed a vestibular schwannoma. Therefore, we recommend early diagnosis and treatment for these patients, especially people with headaches, vomiting, and sudden hearing loss during pregnancy. Herein, we concluded that our cases provide a valuable experience in the latest acceptable time frame for the operation to prevent irreversible neurological impairment and premature delivery in late pregnancy.

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

Epidemiology and Risk Factors for Development of Sporadic Vestibular Schwannoma

Vestibular schwannomas (VSs) are benign, slow-growing tumors of the eighth cranial nerve. Sporadic unilateral VSs constitute approximately 95% of all newly diagnosed tumors. There is little known about risk factors for developing sporadic unilateral VS. Potential risk factors that have been reported are familial or genetic risk, noise exposure, cell phone use, and ionizing radiation, whereas protective factors may include smoking and aspirin use. More research is needed to elucidate the risk factors for development of these rare tumors.

EANO guideline on the diagnosis and treatment of vestibular schwannoma

The level of evidence to provide treatment recommendations for vestibular schwannoma is low compared with other intracranial neoplasms. Therefore, the vestibular schwannoma task force of the European Association of Neuro-Oncology assessed the data available in the literature and composed a set of recommendations for health care professionals. The radiological diagnosis of vestibular schwannoma is made by magnetic resonance imaging. Histological verification of the diagnosis is not always required. Current treatment options include observation, surgical resection, fractionated radiotherapy, and radiosurgery. The choice of treatment depends on clinical presentation, tumor size, and expertise of the treating center. In small tumors, observation has to be weighed against radiosurgery, in large tumors surgical decompression is mandatory, potentially followed by fractionated radiotherapy or radiosurgery. Except for bevacizumab in neurofibromatosis type 2, there is no role for pharmacotherapy.

Association between socioeconomic indicators and geographic distribution of vestibular schwannomas in West Scotland: a 15-year review

OBJECTIVE

Socioeconomic risk factors may contribute to geographic variation in diseases, but studies are limited due to lack of large available cohorts.

METHOD

A geographic analysis was performed of the association between socioeconomic risk factors and the distribution of vestibular schwannomas in adults diagnosed with sporadic vestibular schwannomas through the National Health Services in the West of Scotland from 2000 to 2015.

RESULTS

A total of 511 sporadic vestibular schwannomas were identified in a population of over 3.1 million. Prevalence of vestibular schwannomas were lowest in cases with good health (-0.64, 95 per cent confidence interval: -0.93,-0.38; p = 0.002) and level 1 qualifications (-0.562, 95 per cent confidence interval: -0.882 to -0.26; p = 0.01). However, these risk factors did not demonstrate consistent linearity of correlations. Prevalence was lower in people originating from European Union accession countries from April 2001 to March 2011 (-0.63, 95 per cent confidence interval: -0.84 to -0.43; p = 0.002). No correlation between distribution of vestibular schwannomas and socioeconomic risk factors met our threshold criteria (± 0.7).

CONCLUSION

This study demonstrated that there is little variation in distribution of vestibular schwannomas by socioeconomic risk factors.

Epidemiology of meningiomas

More than 70,000 primary central nervous system tumors are diagnosed in the United States each year. Approximately 36% of these are meningiomas, making it the most common primary brain tumor. Because meningioma risk increases dramatically with age, the healthcare burden of meningioma in the developed world will continue to rise as demographics shift toward an older population. In addition to demographic factors associated with increased meningioma risk (i.e., older age, female sex, African American ethnicity), increased body mass index is a strong risk factor. A history of atopic allergies, eczema, and increased serum IgE are all consistently associated with reduced meningioma risk, suggesting a potential role for immunosurveillance. Although ionizing radiation is a strong meningioma risk factor, it accounts for very few cases at the population level. Recent studies suggest that diagnostic radiation (e.g., dental X-rays) increases meningioma risk. Because radiation dosages associated with medical imaging have decreased dramatically, the public health impact of this exposure is likely in decline. Genome-wide association studies have identified common inherited variants in the gene MLLT10 and RIC8A as low-penetrance meningioma risk alleles. To provide further insight into the etiology of meningioma, future studies will need to simultaneously examine genetic and environmental risk factors, while also stratifying analyses by subject sex.

Epidemiology Of Vestibular Schwannomas - Prospective 40-Year Data From An Unselected National Cohort

Objective

Reports on the epidemiology of vestibular schwannoma (VS) indicate an increase in diagnosed cases, often based on selected materials over a limited period of time. This report presents prospective 40-year epidemiological data from an unselected national cohort of all patients diagnosed with a VS in Denmark since 1976.

Study-design

Data on gender, age, tumor localization and size registered during the period 1976–2015 were retrieved.

Results

3637 new cases of VS were diagnosed during the 40-year period. The annual number of diagnosed VS increased from 14 in 1976 to 193 in 2015. Mean extrameatal tumor size decreased from 26mm in 1976 to 13.4mm in 2015. Large and giant tumors were more frequent during the first decades, whereas predominantly smaller tumors were diagnosed during the recent years. Median age at diagnosis increased gradually from 49.2 years in 1976 to 60 years in 2015.

Conclusion

Over the past 40 years, the incidence rate of vestibular schwannomas has increased steadily from 3 VS/million/year to 34 VS/million/year, primarily due to easier access to improved diagnostics and the finding of more tumors in older people. Concurrently, the diagnostic tumor size has decreased from 26mm to 7mm, and the age at diagnosis has increased from 49 to 60 years.

Risk factors for childhood and adult primary brain tumors

Primary brain tumors account for ~1% of new cancer cases and ~2% of cancer deaths in the United States; however, they are the most commonly occurring solid tumors in children. These tumors are very heterogeneous and can be broadly classified into malignant and benign (or non-malignant), and specific histologies vary in frequency by age, sex, and race/ethnicity. Epidemiological studies have explored numerous potential risk factors, and thus far the only validated associations for brain tumors are ionizing radiation (which increases risk in both adults and children) and history of allergies (which decreases risk in adults). Studies of genetic risk factors have identified 32 germline variants associated with increased risk for these tumors in adults (25 in glioma, 2 in meningioma, 3 in pituitary adenoma, and 2 in primary CNS lymphoma), and further studies are currently under way for other histologic subtypes, as well as for various childhood brain tumors. While identifying risk factors for these tumors is difficult due to their rarity, many existing datasets can be leveraged for future discoveries in multi-institutional collaborations. Many institutions are continuing to develop large clinical databases including pre-diagnostic risk factor data, and developments in molecular characterization of tumor subtypes continue to allow for investigation of more refined phenotypes. Key Point 1. Brain tumors are a heterogeneous group of tumors that vary significantly in incidence by age, sex, and race/ethnicity.2. The only well-validated risk factors for brain tumors are ionizing radiation (which increases risk in adults and children) and history of allergies (which decreases risk).3. Genome-wide association studies have identified 32 histology-specific inherited genetic variants associated with increased risk of these tumors.

Vestibular Schwannoma Growth With Aspirin and Other Nonsteroidal Anti-inflammatory Drugs

OBJECTIVE

To investigate whether the use of aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) impact the growth of vestibular schwannoma (VS).

STUDY DESIGN

Retrospective case series.

SETTING

Single academic, tertiary care center.

PATIENTS

Patients with VS who underwent at least two magnetic resonance imaging (MRI) studies before intervention.

INTERVENTION(S)

Serial MRI studies.

MAIN OUTCOME MEASURE(S)

VS tumor growth, defined as more than or equal to 2 mm increase in the maximum tumor diameter between consecutive MRI studies, or between the first and last available study. Mean growth rate was also calculated, defined as the change in tumor size divided by length of follow-up.

RESULTS

A total of 564 VS patients met inclusion criteria, with 234 (41.2%) taking some type of NSAID. Aspirin use was not associated with VS tumor growth, presenting tumor diameter, or mean VS growth rate. Further, aspirin dosage did not impact growth outcomes or presenting tumor diameter. A total of 96 (17.0%) patients took an NSAID other than aspirin. Neither non-aspirin NSAID use nor degree of cyclooxygenase-2 (COX-2) selectivity, including aspirin, was significantly associated with VS tumor growth, presenting tumor diameter, or mean VS growth rate.

CONCLUSIONS

While previous studies have suggested a relationship between aspirin usage and VS growth, we found no significant association in our series of 564 observed VS. Furthermore, there was no apparent relationship between aspirin dosage, non-aspirin NSAID use, and COX-2 selectivity with VS growth, presenting tumor diameter at presentation, or mean VS growth rate.

Vestibular schwannoma appears to be very rare in a region of Sub-Saharan Africa

BACKGROUND

Vestibular schwannoma (VS) is a significant neurosurgical problem hence it enjoys a special attention at conferences and workshops. It accounts for about 8-10% of all intracranial tumors with an annual incidence of about 11-14 per million per year. Most VS are sporadic with 5-10% attributed to neurofibromatosis type 2 (NF2). However, VS is alleged to be rare in Africans and uncommon in African Americans, connoting a racial bias. To our knowledge, no study from sub-Saharan Africa has addressed this subject. The aim of this study is to determine the frequency of VS in a tertiary neurosurgical hospital in sub-Saharan Africa.

METHODS

This is a retrospective study of all intracranial neoplasms and VS managed in a major tertiary hospital in sub-Saharan Africa from January 2003 to December 2015. Patients' records and neuroimaging studies were reviewed retrospectively. Additionally, database of all cranial computed tomography (CT) and magnetic resonance imaging (MRI) done for various indications within the same period was searched retrospectively for "incidental" VS cases.

RESULTS

Over the study period of 13 years, out of 612 cases of intracranial neoplasms, only three (0.49%) were VSs (two sporadic, one bilateral VS in NF2). A search for "incidental" cases of VS from a pool of 7475 cranial scans (CT: 5290; MRI: 2185), yielded none.

CONCLUSIONS

The findings strongly suggest that VS is very rare in the study population. It is hoped that other centers in Africa and beyond would perform similar studies.

Geographic distribution of vestibular schwannomas in West Scotland between 2000-2015

Background

Although the natural history of vestibular schwannomas (VS) has been previously studied, few studies have investigated associated epidemiological factors, primarily because of the lack of large available cohorts.

Objective

The objective of this study was to perform a multi-scale geographical analysis of the period prevalence of VS in West Scotland from 2000 to 2015.

Methods

Adults diagnosed with sporadic VS were identified through the National Health Services of West Scotland database and geocoded to the unit postcode. To assess whether the cohort of VS cases could be pooled into a period prevalence measure, the locations of VS cases were analyzed by sex using Cross-L and Difference-K functions. VS period prevalence was examined at two aggregate spatial scales: the postcode district and a coarser scale of NHS Health Boards. The spatial structure of period prevalence within each level of spatial aggregation was measured using univariate global and local Moran’s I. Bivariate local Moran’s I was used to examine the between-scale variability in period prevalence from the postcode district level to the NHS Health Boards levels. Prior to spatial autocorrelation analyses, the period prevalence at the postcode district was tested for stratified spatial heterogeneity within the NHS Health Boards using Wang’s q-Statistic.

Results

A total of 512 sporadic VS were identified in a population of over 3.1 million. Between 2000 and 2015, VS period prevalence was highest within the NHS Health Boards of Greater Glasgow and Clyde, Ayrshire and Arran and the Western Isles. However, at the NHS scale, period prevalence exhibited no spatial autocorrelation globally or locally. At the district scale, Highland exhibited the most unusual local spatial autocorrelation. Bivariate local Moran’s I results indicated general stability of period prevalence across the postcode district to Health Boards scales. However, locally, some postcode districts in Greater Glasgow and Clyde, Ayrshire and Arran exhibited unusually low district to zone spatial autocorrelation in period prevalence, as did the southern parts of the Western Isles. Some unusually high period prevalence values between the postcode district to Health Board scale were found in Tayside, Forth Valley and Dumfries and Galloway.

Conclusion

Geographic variability in VS in West Scotland was identified in this patient population, showing that there are areas, even remote, with unusually high or low period prevalence. This can be partially attributed to links between primary and tertiary care. Potential genetic or environmental risk factors that may contribute to geographic variation in this disease within Scotland are also a possibility but require further investigation.

Risk Factors of Acoustic Neuroma: Systematic Review and Meta-Analysis

PURPOSE

Many epidemiological studies have investigated environmental risk factors for the development of acoustic neuroma. However, these results are controversial. We conducted a meta-analysis of case-control studies to identify any potential relationship between history of noise exposure, smoking, allergic diseases, and risk of acoustic neuroma.

MATERIALS AND METHODS

We searched PubMed to identify relevant articles. Two researchers evaluated the eligibility and extracted the data independently.

RESULTS

Eleven case-control studies were included in our meta-analysis. Acoustic neuroma was found to be associated with leisure noise exposure [odds ratio (OR)=1.33, 95% confidence interval (CI): 1.05-1.68], but not with occupational noise exposure and ever noise exposure (OR=1.20, 95% CI: 0.84-1.72 and OR=1.15, 95% CI: 0.80-1.65). The OR of acoustic neuroma for ever (versus never) smoking was 0.53 (95% CI: 0.30-0.94), while the subgroup analysis indicated ORs of 0.95 (95% CI: 0.81-1.10) and 0.49 (95% CI: 0.41-0.59) for ex-smoker and current smoker respectively. The ORs for asthma, eczema, and seasonal rhinitis were 0.98 (95% CI: 0.80-1.18), 0.91 (95% CI: 0.76-1.09), and 1.52 (95% CI: 0.90-2.54), respectively.

CONCLUSION

Our meta-analysis is suggestive of an elevated risk of acoustic neuroma among individuals who were ever exposed to leisure noise, but not to occupational noise. Our study also indicated a lower acoustic neuroma risk among ever and current cigarette smokers than never smokers, while there was no significant relationship for ex-smokers. No significant associations were found between acoustic neuroma and history of any allergic diseases, such as asthma, eczema, and seasonal rhinitis.

Smoking and Glioma Risk: Evidence From a Meta-Analysis of 25 Observational Studies

To systematically assess the relationship between smoking and glioma risk.A dose-response meta-analysis of case-control and cohort studies was performed. Pertinent studies were identified by searching database and reference lists. Random-effects model was employed to pool the estimates of the relative risks (RRs) with corresponding 95% confidence intervals (CIs).A total of 19 case-control and 6 cohort studies were included. Overall, compared with those who never smoked, the pooled RR and 95% CI was 0.98 (0.92-1.05) for ever smoker. The subgroups were not significantly different regarding risk of glioma except the group of age at start smoking (RR = 1.17, 95% CI: 0.93-1.48 for age < 20; RR = 1.25, 95% CI: 1.02-1.52 for age ≥ 20). Dose-response analysis also suggested no significant association between smoking and the risk of glioma, although some evidence for a linear relationship between smoking and glioma risk was observed.In conclusion, this meta-analysis provides little support for a causal relationship between smoking and risk of glioma.

Epidemiology and Environmental Risk Factors Associated with Vestibular Schwannoma

OBJECTIVE

Vestibular schwannomas (VS) are tumors originating from the eighth cranial nerve. The etiology and environmental risk factors for VS remain unclear. The goal of this study was to explore some potential environmental risk factors associated with vestibular schwannoma (VS).

METHODS

A hospital-based case-control study with 1:1 matching based on age and sex was designed. A written questionnaire was administered. Multiple conditional logistic regression models were created to determine odds ratio (OR).

RESULTS

There were 353 matched pairs with an average age at diagnosis of 53 years (SD ± 12), 50% of participants were female, and >90% were white. Multivariate models revealed significantly increased OR with a history of hay fever (OR = 3.91, 95% confidence interval [CI] = 1.35-11.30) and managerial/professional occupations (OR = 4.41, 95% CI = 2.07-9.40). Tobacco use had a decreased association with VS (<20 pack-years OR = 0.10, 95% CI = 0.04-0.28; ≥ 20 pack-years OR = 0.03, 95% CI = 0.01-0.12).

CONCLUSIONS

The profile of patients with VS includes white race, age 50-60 years, either sex, and working in a professional occupation. Better access to health care and diagnostic imaging likely plays a role in the diagnosis of this tumor. Hay fever is strongly associated with VS. Tobacco use demonstrates an inverse relationship with VS, but the possible biologic mechanism for this is poorly understood, and tobacco remains a significant public health problem.

Body mass index and the risk of meningioma, glioma and schwannoma in a large prospective cohort study (The HUNT Study)

BACKGROUND

Obesity increases the risk for a number of solid malignant tumours. However, it is not clear whether body mass index (BMI) and height are associated with the risk of primary tumours of the central nervous system (CNS).

METHODS

In a large population study (The Nord-Trøndelag Health Study (HUNT Study)) of 74 242 participants in Norway, weight and height were measured. During follow-up, incident CNS tumours were identified by individual linkage to the Norwegian Cancer Registry. Sex- and age-adjusted and multivariable Cox regression analyses were used to evaluate BMI and height in relation to the risk of meningioma, glioma and schwannoma.

RESULTS

A total of 138 meningiomas, 148 gliomas and 39 schwannomas occurred during 23.5 years (median, range 0-25) of follow-up. In obese women (BMI ≥ 30 kg m(-2)), meningioma risk was 67% higher (hazard ratio (HR)=1.68, 95% confidence interval (CI): 0.97-2.92, P-trend=0.05) than in the reference group (BMI 20-24.9 kg m(-2)), whereas no association with obesity was observed in males. There was no association of BMI with glioma risk, but there was a negative association of overweight/obesity (BMI ≥ 25 kg m(-2)) with the risk of schwannoma (HR=0.48, 95% CI: 0.23-0.99). However, the schwannoma analysis was based on small numbers. Height was not associated with the risk for any tumour subgroup.

CONCLUSION

These results suggest that BMI is positively associated with meningioma risk in women, and possibly, inversely associated with schwannoma risk.

Sex and age associations with vestibular schwannoma size and presenting symptoms

OBJECTIVE

To assess the association of sex and age with presenting symptoms and size of vestibular schwannoma at clinical presentation to our clinics.

STUDY DESIGN

Retrospective chart review.

SETTING

Academic medical center.

PATIENTS

Approximately 1,269 subjects diagnosed with unilateral vestibular schwannoma between 1997 and 2010.

INTERVENTION

Demographic information, tumor characteristics, and treatment strategy were recorded.

MAIN OUTCOME MEASURE

Tumor size, patient-reported presence of hearing loss or dizziness at presentation.

RESULTS

Male subjects had significantly larger tumors than female subjects at presentation (18.23 versus 16.81 mm, p = 0.031); this difference was particularly pronounced in patients younger than 40 years. Patient-reported symptoms at baseline also differed by sex: the prevalence of hearing loss was 95.1% in male subjects versus 90.3% in female subjects (p = 0.001), and the frequency of dizziness was 74.3% in female subjects versus 59.0% in male subjects (p<0.0001). In multivariate analyses, male subjects continued to have a borderline significant positive association with tumor size (p = 0.066) and were 2-fold more likely to have hearing loss (odds ratio [OR], 2.082; 95% confidence interval [CI], 1.300-3.336) but half as likely to have dizziness (OR, 0.501; 95% CI, 0.387-0.649) than female subjects. Additionally, for every 1-mm increase in tumor size, patients were more likely to report hearing loss by 14.7% (OR, 1.147; 95% CI, 1.106-1.191) and dizziness by 2.8% (OR, 1.028; 95% CI, 1.016-1.041).

CONCLUSION

We observed significant sex differences in the presentation and size of unilateral vestibular schwannomas. As management and treatment strategies are predicated on presenting symptoms and patient factors, these observations merit further study to further understand tumor biology, improve risk stratification, and optimize tumor management.

Allergy and brain tumors in the INTERPHONE study: pooled results from Australia, Canada, France, Israel, and New Zealand

PURPOSE

A history of allergy has been inversely associated with several types of cancer although the evidence is not entirely consistent. We examined the association between allergy history and risk of glioma, meningioma, acoustic neuroma, and parotid gland tumors using data on a large number of cases and controls from five INTERPHONE study countries (Australia, Canada, France, Israel, New Zealand), to better understand potential sources of bias in brain tumor case-control studies and to examine associations between allergy and tumor sites where few studies exist.

METHODS

A total of 793 glioma, 832 meningioma, 394 acoustic neuroma, and 84 parotid gland tumor cases were analyzed with 2,520 controls recruited during 2000-2004. Conditional logistic regression models were used to obtain odds ratios (ORs) and 95 % confidence intervals (CIs) for associations between self-reported allergy and tumor risk.

RESULTS

A significant inverse association was observed between a history of any allergy and glioma (OR = 0.73, 95 % CI 0.60-0.88), meningioma (OR = 0.77, 95 % CI 0.63-0.93), and acoustic neuroma (OR = 0.64, 95 % CI 0.49-0.83). Inverse associations were also observed with specific allergic conditions. However, inverse associations with asthma and hay fever strengthened with increasing age of allergy onset and weakened with longer time since onset. No overall association was observed for parotid gland tumors (OR = 1.21, 95 % CI 0.73-2.02).

CONCLUSIONS

While allergy history might influence glioma, meningioma, and acoustic neuroma risk, the observed associations could be due to information or selection bias or reverse causality.

Epidemiology: allergy history, IgE, and cancer

Numerous epidemiological studies have investigated potential associations between allergy history and cancer risk with strong inverse associations reported in studies of pancreatic cancer, glioma, and childhood leukemia. Recently, there has been a rapid expansion of the epidemiological literature both of studies evaluating self-reported allergy history in relation to cancer risk and of studies evaluating biological indicators of allergy history and immune function including levels of immunoglobulin (Ig) E. However, there are several potential methodological limitations associated with prior studies, and further research is required to clarify associations observed. This paper summarizes the recent epidemiological literature examining associations between allergy history and cancer risk. From 2008, a total of 55 epidemiological studies were identified that examined some aspect of the association between allergy and cancer. Although the majority of studies examined self-reported allergy history in relation to cancer risk, there were also studies examining allergy diagnoses or discharges as captured in existing administrative databases, levels of IgE, polymorphisms of allergy, inflammatory- or allergy-related cytokine genes, and concentrations of immune regulatory proteins. The most frequently studied cancer sites included brain and lymphatic and hematopoietic cancers. Potential methodological sources of bias are discussed as well as recommendations for future work.

Role of tobacco use in the etiology of acoustic neuroma

Two previous studies suggest that cigarette smoking reduces acoustic neuroma risk; however, an association between use of snuff tobacco and acoustic neuroma has not been investigated previously. The authors conducted a case-control study in Sweden from 2002 to 2007, in which 451 cases and 710 population-based controls completed questionnaires. Cases and controls were matched on gender, region, and age within 5 years. The authors estimated odds ratios using conditional logistic regression analyses, adjusted for education and tobacco use (snuff use in the smoking analysis and smoking in the snuff analysis). The risk of acoustic neuroma was greatly reduced in male current smokers (odds ratio (OR) = 0.41, 95% confidence interval (CI): 0.23, 0.74) and moderately reduced in female current smokers (OR = 0.70, 95% CI: 0.40, 1.23). In contrast, current snuff use among males was not associated with risk of acoustic neuroma (OR = 0.94, 95% CI: 0.57, 1.55). The authors' findings are consistent with previous reports of lower acoustic neuroma risk among current cigarette smokers than among never smokers. The absence of an association between snuff use and acoustic neuroma suggests that some constituent of tobacco smoke other than nicotine may confer protection against acoustic neuroma.

Primary brain tumours and specific serum immunoglobulin E: a case-control study nested in the European Prospective Investigation into Cancer and Nutrition cohort

BACKGROUND

Case-control studies suggest that patients with allergic diseases have a lower risk of developing glioma but not meningioma or schwannoma. However, those data can be differentially biased. Prospective studies with objective measurements of immunologic biomarkers, like immunoglobulin E (IgE), in blood obtained before cancer diagnosis could help to clarify whether an aetiological association exists.

METHODS

The present case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) measured specific serum IgE as a biomarker for the most common inhalant allergens in 275 glioma, 175 meningioma and 49 schwannoma cases and 963 matched controls using the ImmunoCAP specific IgE test. Subjects with an IgE level ≥0.35 kUA/l (kilo antibody units per litre) were classified as sensitized by allergens. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by adjusted conditional logistic regression models for each tumour subtype. The effect of dose-response relationship was assessed in five increasing IgE level categories to estimate P-values for trend.

RESULTS

The risk of glioma was inversely related to allergic sensitization (OR = 0.73; 95% CI 0.51-1.06), especially pronounced in women (OR = 0.53; 95% CI 0.30-0.95). In dose-response analyses, for high-grade glioma, the lowest OR was observed in sera with the highest IgE levels (P for trend = 0.04). No association was seen for meningioma and schwannoma.

CONCLUSION

The results, based on serum samples prospectively collected in a cohort study, provide some support for the hypothesis that individuals with allergic sensitization are at reduced risk of glioma and confirm results from previous case-control studies.

Incidence trends of vestibular schwannomas in Denmark, Finland, Norway and Sweden in 1987-2007

Background:

The reported incidence rates of vestibular schwannomas (VS) vary substantially, but it is unclear as to what extent the variation reflects differences in risk or recording practices. Our aim was to describe the incidence rates of VS in Denmark, Finland, Norway and Sweden between 1987 and 2007.

Methods:

Comprehensive data were available from all registries only for the period from 1987 to 2007. An analysis of a longer time period (1965–2007) was conducted with the Norwegian and Swedish data.

Results:

The average age-standardised incidence rates during 1987–2007 varied from 6.1 per 1 000 000 person-years (95% confidence interval (CI), 5.4–6.7) among Finnish men to 11.6 (95% CI, 10.4–12.7) in Danish men, and from 6.4 per 1 000 000 person-years (95% CI, 5.7–7.0) among Swedish women to 11.6 (95% CI, 10.5–12.8) among Danish women. An overall annual increase of 3.0% (95% CI 2.1–3.9) was observed when all countries and both sexes were combined, with considerable differences between countries. However, the practices of both reporting and coding VS cases varied markedly between countries and over time, which poses a challenge for interpretation of the results.

Conclusion:

The overall incidence of VS increased in all the four Nordic countries combined between 1987 and 2007, with marked differences between countries. However, the incidence rates more or less stabilised in the late 1990s, showing relatively constant incidence rates and even some decline after 2000.

Sociodemographic factors and vestibular schwannoma: a Danish nationwide cohort study

Vestibular schwannoma (VS) (or acoustic neuroma) accounts for about 5%-6% of all intracranial tumors; little is known about the etiology. We investigated the association between various sociodemographic indicators and VS in a cohort of 3.26 million Danish residents, with 1087 cases identified in 35 308 974 person-years under risk, with data accrued from 1993 to 2006. Complete ascertainment of cases was ensured by using population-based and clinical cancer registries. Information on sociodemographic indicators was obtained on an annually updated individual level from Statistics Denmark. Log-linear Poisson regression models were used to estimate incidence rate ratios (IRRs). Linear regression models were used to examine the association between sociodemographic indicators and tumor size. We found that IRRs decreased gradually with decreasing level of education, with values of 0.62 (95% CI: 0.49-0.78) for men and 0.62 (95% CI: 0.50-0.77) for women with a basic education compared with a higher education. Similar results were found for disposable income. Marital status was associated with a higher incidence of VS in men but not women; nonmarried men with a basic education had an IRR of 0.34 (95% CI: 0.23-0.50) compared with married men with a higher education. Lower incidence rates were also observed among unemployed or early-retirement pensioners, whereas there were no differences in incidence rates across the broad groups of occupations and across the types of districts. Sociodemographic indicators were not associated with the tumor size. The magnitude of the differences in incidence rates across the groups of different socioeconomic indicators suggests a high potential for earlier diagnosis of VS by improving the awareness of early symptoms.

Cigarette smoking and risk of acoustic neuromas and pituitary tumours in the Million Women Study

Background:

The relationship between cigarette smoking and incidence of acoustic neuromas and pituitary tumours is uncertain.

Methods:

We examined the relation between smoking and risk of acoustic neuromas and pituitary tumours in a prospective study of 1.2 million middle-aged women in the United Kingdom.

Results:

Over 10.2 million person years of follow-up, 177 women were diagnosed with acoustic neuromas and 174 with pituitary tumours. Current smokers at recruitment were at significantly reduced risk of incident acoustic neuroma compared with never smokers (adjusted relative risk (RR)=0.41, 95% confidence interval (CI)=0.24–0.70, P=0.001). Past smokers did not have significantly different risk of acoustic neuroma than never smokers (RR=0.87, 95% CI=0.62–1.22, P=0.4). Smoking was not associated with incidence of pituitary tumours (RR in current vs never smokers=0.91, 95% CI=0.60–1.40, P=0.7).

Conclusion:

Women who smoke are at a significantly reduced risk of acoustic neuromas, but not of pituitary tumours, compared with never smokers. Acoustic neuromas are much rarer than the cancers that are increased among smokers.

The INTERPHONE study: design, epidemiological methods, and description of the study population

The very rapid worldwide increase in mobile phone use in the last decade has generated considerable interest in the possible health effects of exposure to radio frequency (RF) fields. A multinational case-control study, INTERPHONE, was set-up to investigate whether mobile phone use increases the risk of cancer and, more specifically, whether the RF fields emitted by mobile phones are carcinogenic. The study focused on tumours arising in the tissues most exposed to RF fields from mobile phones: glioma, meningioma, acoustic neurinoma and parotid gland tumours. In addition to a detailed history of mobile phone use, information was collected on a number of known and potential risk factors for these tumours. The study was conducted in 13 countries. Australia, Canada, Denmark, Finland, France, Germany, Israel, Italy, Japan, New Zealand, Norway, Sweden, and the UK using a common core protocol. This paper describes the study design and methods and the main characteristics of the study population. INTERPHONE is the largest case-control study to date investigating risks related to mobile phone use and to other potential risk factors for the tumours of interest and includes 2,765 glioma, 2,425 meningioma, 1,121 acoustic neurinoma, 109 malignant parotid gland tumour cases and 7,658 controls. Particular attention was paid to estimating the amount and direction of potential recall and participation biases and their impact on the study results.

Environmental risk factors for sporadic acoustic neuroma (Interphone Study Group, Germany)

The only known risk factor for sporadic acoustic neuroma is high-dose ionising radiation. Environmental exposures, such as radiofrequency electromagnetic fields and noise are under discussion, as well as an association with allergic diseases. We performed a population-based case-control study in Germany investigating these risk factors in 97 cases with acoustic neuroma, aged 30 to 69 years, and in 194 matched controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in multiple logistic regression models. Increased risks were found for exposure to persistent noise (OR=2.31; 95% CI 1.15-4.66), and for hay fever (OR=2.20; 95% CI 1.09-4.45), but not for ionising radiation (OR=0.91; 95 % CI 0.51-1.61) or regular mobile phone use (OR=0.67; 95% CI 0.38-1.19). The study confirms results of recently published studies, although the pathogenetic mechanisms are still unknown.