Risk Of Brain Cancer Research Articles

Cumulative exposure and lifetime cancer risk from diagnostic radiation in patients undergoing orthognathic surgery: a cross-sectional analysis

Radiation doses in dentomaxillofacial imaging are typically very low. However, diagnostic and follow-up protocols in orthognathic surgery result in a patient-specific risk in effective dose. Estimating the cancer risks from these exposures remains abstract for many maxillofacial surgeons. In this study, 40 orthognathic patients were randomly sampled and their cumulative effective dose (ED) calculated. The lifetime attributable risk of cancer (LAR) was calculated based on the standard radiological protocol for orthognathic surgery follow-up using methods described in the BEIR VII report and RadRAT. The mean cumulative ED of the 40 sampled patients at the end of their 2-year follow-up period was 1.91 ± 0.58 mSv. The LAR at the end of follow-up was 17.65 (90% confidence interval 6.46–32.90) per 100,000 person-years for male orthognathic patients and 13.93 (90% confidence interval 6.27–25.24) per 100,000 person-years for female orthognathic patients. This represents 0.70% and 0.68%, respectively, of the baseline cancer risk for oral, thyroid, and brain cancer combined. Although theoretical, these results provide a framework for interpreting radiation doses and cancer risks in patients undergoing orthognathic surgery. Considering the increased radiation sensitivity in children and adolescents, indication-oriented and patient-specific imaging protocols should be advised.

Evaluating the Necessity and Radiation Risk of Brain CT Scans Requested by the Trauma Emergency Department.

Numerous Computed Tomography (CT) scan requests for trauma patients have raised serious concern about the impacts of radiation such as radiation-induced cancers. This study aimed to evaluate the necessity rate of requested head CT scans for traumatic patients and to ultimately estimate the risk of radiation-induced brain cancer. In this retrospective analytical study, traumatic patients, who had undergone a head CT scan in a two-month period from August 23 to October 22, 2018, were considered as the study population. Two radiologists reviewed each patient individually to evaluate the rate of normal and abnormal cases. Dose length product in milligrays (mGy) was utilized to calculate the effective dose (ED) in millisieverts (mSv), resulting in an assessment of the risk of radiation-induced brain cancer using ICRP 103. Among 523 scans, 460 patients (88%) received normal reviews, while only 47 patients (9%) had findings related to their current trauma. The mean effective dose value was 1.05±0.36 mSv. Risk of the radiation induced brain cancer was calculated to be 0.037 and 0.030 new cancer cases in 10000 males and females per Gy, respectively. Final results demonstrated that a significant number of traumatic patients undergoing a CT scan are in fact, healthy. Such reckless usage of CT and consequently the excess exposure could result in a dramatic rise in cancer rates. The need to limit unnecessary CT scan usage and keeping the radiation given to patients as low as reasonably achievable (ALARA) when collecting essential diagnostic data is more critical than ever.

Positive Association Between the Immunogenetic Human Leukocyte Antigen (HLA) Profiles of Multiple Sclerosis and Brain Cancer.

Previous research has documented elevated risk of brain cancer in patients with multiple sclerosis (MS). Separately, human leukocyte antigen (HLA) has been implicated in protection or susceptibility for both conditions. The aim of the current study was to assess a possible role of shared immunogenetic influence on risk of MS and brain cancer. We first identified an immunogenetic profile for each condition based on the covariance between the population frequency of 127 high-resolution HLA alleles and the population prevalence of each condition in 14 Continental Western European countries and then evaluated the correspondence between MS and brain cancer immunogenetic profiles. Also, since each individual carries 12 HLA alleles (2 × 6 genes), we estimated HLA protection and susceptibility for MS and brain cancer at the individual level. We found that the immunogenetic profiles of MS and brain cancer were highly correlated overall (P < .001) and across all 6 HLA genes with the strongest association observed for DRB1, followed by DQB1 and HLA-A. These findings of immunogenetic overlap between MS and brain cancer are discussed in light of the role of HLA in the immune system response to viruses and other foreign antigens.

Eczema as a protective factor for brain cancer: a meta-analysis

BackgroundBrain cancer is one of the most aggressive cancer types owing to poor treatment effects. Epidemiological studies have demonstrated that allergies may increase the disease risk. Therefore, this study evaluated the association between eczema and the risk of various brain cancers.MethodsWe systematically searched the PubMed and Embase databases from their inception until June 23, 2022. Two reviewers independently reviewed and screened the articles, extracted data, assessed the study quality, and pooled the results. Stata software was used to generate pooled odds ratios and 95% confidence intervals (CIs).ResultsWe included 20 studies comprising 5,117,222 patients that investigated the relationship between eczema and brain cancer. Eczema was significantly inversely associated with the risk of brain cancer (odds ratio [OR], 0.82; 95% CI, 0.77–0.87), glioma (OR, 0.53; 95% CI, 0.14–2.02), meningioma (OR, 0.74; 95% CI, 0.66–0.84), and acoustic neuroma (OR, 0.60; 95% CI, 0.41–0.88). Interesting, The strong correlation between eczema and the reduced risk of brain cancer was observed in people over 16 years old (OR, 0.79; 95% CI, 0.71–0.88), but not in those under 16 years old (OR, 0.94; 95% CI, 0.79–1.11). In addition, subgroup analyses found that eczema significantly decreased the glioma risk in Europeans (OR, 0.73; 95% CI, 0.65–0.82) but not Australians (OR, 0.53; 95% CI, 0.14–2.02) or Americans (OR, 1.01; 95% CI, 0.69–1.46).ConclusionEczema may be considered as a potential protective factor of brain cancer in population aged over 16 years. However, this relationship requires verification using large-scale clinical data.

Preliminary study of a novel radiation shield for jaw in dental radiography using the high-density polyethylene/bismuth oxide nanocomposite

Dental radiography has been linked in numerous studies to an elevated risk of brain cancer, meningioma cranial tumors, and parotid gland tumors. Unfortunately, not much attention has been given to this problem. This research aims to determine and quantify the radiation shielding properties of High-Density Polyethylene/Bismuth Oxide composite (HDPE-Bi2O3) including the linear attenuation coefficient (μ), mass attenuation coefficient (μ/ρ), half-value layer (HVL) and tenth-value layer (TVL) for photons at 59.5 keV. First, the MCNP code—which showed a reasonable degree of consistency with the XCOM data—was used to simulate the variables μ, μ/ρ, HVL, and TVL that were connected to different concentrations of the composite. Then, the nanocomposite containing of 60 wt% Bi2O3 was chosen and fabricated via the casting method. There were XRD, and FESEM tests performed. Two techniques using the CsI(Tl) scintillation detector and the Geiger counter were applied to measure the shielding quantities at 59.5 keV gamma-rays of the 241Am radioactive source. Finally, results of the measurements revealed a comparatively good agreement with the values from the MCNP and XCOM simulations, with a maximum 3% discrepancy. The artifact test at the presence of the composites shield using a dental radiographic system at 60 kV have not been influenced adversely. This composite at the optimal weight fraction and thickness has potential application to be used as a radiation shield for jaw in dental radiography.

Cancer risk among HIV-exposed uninfected children in the United States.

In utero exposure to didanosine was associated with increased risk of brain cancer in a French study. We used United States health department records to assess cancer risk among 13 617 children exposed to HIV in utero , who remained HIV-uninfected after birth (1990-2017). Risk of brain tumors was borderline elevated among these children (standardized incidence ratio 2.2, 95% confidence interval 0.8-4.8, P = 0.12, based on six cases). Risk was not significantly increased for leukemia or other cancers.

New evidence for brain cancer risk after a single paediatric CT scan

Despite the unquestionable benefits of diagnostic radiation exposure, the potential health risks are of considerable concern, particularly for the risk of brain cancer following paediatric head CT examinations. In The Lancet Oncology, Michael Hauptmann and colleagues1 present the results of a large-scale study from nine European countries (the EPI-CT cohort study) to quantify the risks of brain cancer in more than 650 000 patients who had a first head or neck CT examination when they were younger than 22 years.

Brain cancer after radiation exposure from CT examinations of children and young adults: results from the EPI-CT cohort study

The European EPI-CT study aims to quantify cancer risks from CT examinations of children and young adults. Here, we assess the risk of brain cancer. We pooled data from nine European countries for this cohort study. Eligible participants had at least one CT examination before age 22 years documented between 1977 and 2014, had no previous diagnosis of cancer or benign brain tumour, and were alive and cancer-free at least 5 years after the first CT. Participants were identified through the Radiology Information System in 276 hospitals. Participants were linked with national or regional registries of cancer and vital status, and eligible cases were patients with brain cancers according to WHO International Classification of Diseases for Oncology. Gliomas were analysed separately to all brain cancers. Organ doses were reconstructed using historical machine settings and a large sample of CT images. Excess relative risks (ERRs) of brain cancer per 100 mGy of cumulative brain dose were calculated with linear dose-response modelling. The outcome was the first reported diagnosis of brain cancer after an exclusion period of 5 years after the first electronically recorded CT examination. We identified 948 174 individuals, of whom 658 752 (69%) were eligible for our study. 368 721 (56%) of 658 752 participants were male and 290 031 (44%) were female. During a median follow-up of 5·6 years (IQR 2·4-10·1), 165 brain cancers occurred, including 121 (73%) gliomas. Mean cumulative brain dose, lagged by 5 years, was 47·4 mGy (SD 60·9) among all individuals and 76·0 mGy (100·1) among people with brain cancer. A significant linear dose-response relationship was observed for all brain cancers (ERR per 100 mGy 1·27 [95% CI 0·51-2·69]) and for gliomas separately (ERR per 100 mGy 1·11 [0·36-2·59]). Results were robust when the start of follow-up was delayed beyond 5 years and when participants with possibly previously unreported cancers were excluded. The observed significant dose-response relationship between CT-related radiation exposure and brain cancer in this large, multicentre study with individual dose evaluation emphasises careful justification of paediatric CTs and use of doses as low as reasonably possible. EU FP7; Belgian Cancer Registry; La Ligue contre le Cancer, L'Institut National du Cancer, France; Ministry of Health, Labour and Welfare of Japan; German Federal Ministry of Education and Research; Worldwide Cancer Research; Dutch Cancer Society; Research Council of Norway; Consejo de Seguridad Nuclear, Generalitat de Catalunya, Spain; US National Cancer Institute; UK National Institute for Health Research; Public Health England.

Male origin microchimerism and brain cancer: a case-cohort study.

Despite considerable research effort, causes of brain cancer are largely unknown. Male brain cancer predominance and reduced brain cancer risk with increasing parity among women, however, support a favourable role of pregnancy. We set out to determine whether fetal-origin microchimerism, namely the presence and long-term persistence of fetal cells, likely obtained via natural trafficking across the placenta during pregnancy, associates with reduced risk of brain cancer in women. Using a case-cohort design, we sampled 505 middle-aged women randomly at baseline in the Diet, Cancer and Health cohort (controls), and 73 women with incident brain cancer diagnosed during follow-up in the Danish Cancer Registry (cases). Male origin microchimerism was determined by presence of Y chromosome sequences in female blood samples. Data were analysed using weighted proportional Hazards regression, yielding Hazard Ratios with 95% confidence intervals. Compared with male origin microchimerism negative women, positive women had half the risk of developing brain cancer (Hazard Ratio = 0.50 [0.33-0.77]). Sensitivity analyses support that our findings are unlikely due to bias or chance. Here, for the first time, we demonstrate half the risk of brain cancer in male origin microchimerism positive compared with negative women. Our findings resemble those of previous studies of male origin microchimerism and other female cancers.

Meta-analysis of head trauma and subsequent risk of brain cancer comparing R and Stata statistical packages

Meta-analysis of head trauma and subsequent risk of brain cancer comparing R and Stata statistical packages

Association between Blood Donation and Malignant and Benign Tumour Risk: A Population-Based Study of 3.4 Million Participants in China.

This study aims to identify the relationship between blood donation and malignant and benign tumour hospitalization risk. The cohort study was constructed in Shaanxi, China, to include blood donors and match nonblood donors one-to-one by gender, age, and county of residence. The study compared the hospitalization records of two groups from 2012 to 2018. A log-binomial regression model was used to estimate the relative risk (RR) of tumour risk between donors and nonblood donors among different age groups. A total of 1,625,599 donors were recruited (including 968,823 males) and compared with the matched nonblood donor group. Significantly lower risk of malignancy in males was found among donors (adjusted RR: 0.82, 95% CI: 0.75–0.92). Lower risks for specific types of tumours among donors were observed, including liver (0.42, [0.28–0.67]), lung (0.74, [0.59–0.87]), lymphoma (0.75, [0.62–0.85]), and oesophagus (0.55, [0.41–0.72]). However, the risk of brain cancer was higher among male donors (RR 1.19 [1.06–1.29]). Among female donors, lower risk of liver (0.57, [0.42–0.79]) and oesophagus malignancy (0.73, [0.62–0.88]) was observed. For benign tumours, male donors have a lower risk of benign skin tumour (0.79, [0.62–0.94]) and hemangioma and lymphangioma (0.75, [0.51–0.89]), while female donors have a lower risk in hemangioma and lymphangioma (0.65, [0.44–0.83]). We also found that the risk decreased with age among donors in the prevalence of tumours compared to that in nonblood donors (p < 0.05). Blood donation appears to be significantly associated with various tumour risks among both males and females. Overall, the risk of tumours decreased more substantially with age in blood donors compared with nonblood donors. Further research is warranted to investigate the impact of ‘health donor effects' on these findings.

MRI brain image classification using Linear Vector Quantization Classifier

The metastases cancer other than the lifestyle-related or environmental related no known facts for the brain tumors. Only factors that may cause brain tumors might be the exposure to high ionizing radiation and a family history of any brain disease also increase brain cancer risk. The cancerous brain is a brain disorder that shapes masses in cells called tumors. The early diagnosis of brain cancer using the Magnetic Resonance Imaging (MRI) scan image for cancer disease is required to reduce the mortality rate. Dual-Tree Mband Wavelet Transform (DTMBWT) based feature extraction, and Linear Vector Quantization Classifier (LVQC) based MRI brain image classification. DTMBWT decomposes the MRI brain images in the frequency domain as the sub-bands for fuzzy-based low and high components to evaluate the features selected. The Sub-band Energy Features (SEF) for individual and sub-set ranking helps classify normal and abnormal images that LVQC for output prediction characterizes. The results show the classification accuracy of 95% using DTMBWT based SEF and LVQC classifiers.

A novel methodology to train and deploy a machine learning model for personalized dose assessment in head CT.

To propose a machine learning-based methodology for the creation of radiation dose maps and the prediction of patient-specific organ/tissue doses associated with head CT examinations. CT data were collected retrospectively for 343 patients who underwent standard head CT examinations. Patient-specific Monte Carlo (MC) simulations were performed to determine the radiation dose distribution to patients' organs/tissues. The collected CT images and the MC-produced dose maps were processed and used for the training of the deep neural network (DNN) model. For the training and validation processes, data from 231 and 112 head CT examinations, respectively, were used. Furthermore, a software tool was developed to produce dose maps from head CT images using the trained DNN model and to automatically calculate the dose to the brain and cranial bones. The mean (range) percentage differences between the doses predicted from the DNN model and those provided by MC simulations for the brain, eye lenses, and cranial bones were 4.5% (0-17.7%), 5.7% (0.2-19.0%), and 5.2% (0.1-18.9%), respectively. The graphical user interface of the software offers a user-friendly way for radiation dose/risk assessment. The implementation of the DNN allowed for a 97% reduction in the computational time needed for the dose estimations. A novel methodology that allows users to develop a DNN model for patient-specific CT dose prediction was developed and implemented. The approach demonstrated herein allows accurate and fast radiation dose estimation for the brain, eye lenses, and cranial bones of patients who undergo head CT examinations and can be used in everyday clinical practice. • The methodology presented herein allows fast and accurate radiation dose estimation for the brain, eye lenses, and cranial bones of patients who undergo head CT examinations and can be implemented in everyday clinical practice. • The scripts developed in the current study will allow users to train models for the acquisition protocols of their CT scanners, generate dose maps, estimate the doses to the brain and cranial bones, and estimate the lifetime attributable risk of radiation-induced brain cancer.

Parkinson's disease and cancer: a systematic review and meta-analysis on the influence of lifestyle habits, genetic variants, and gender.

Purpose: The relationship between Parkinson’s disease (PD) and cancer has been debated. Gender and genetic influences on cancer development in PD is unclear.Methods: Using QUOROM guidelines, we conducted a systematic review and meta-analysis on potential clinical and genetic factors influencing the PD and subsequent cancer relationship. English articles published in PubMed, Web of Science, and SCOPUS from 2010 to 30 August 2020 were considered for suitability.Results: Of 46 studies identified, fourteen satisfied the inclusion criteria and were further analysed. Unadjusted risk ratios (RR) and 95% confidence intervals were computed to determine the PD and cancer relationship. PD patients have decreased subsequent cancer risks (RR = 0.87, 95% CI = 0.81–0.93), reduced risks of colon, rectal, and colorectal cancer (RR = 0.77, 95% CI = 0.63–0.94), lung cancer (RR = 0.62, 95% CI = 0.48–0.80), and increased brain cancer (R = 1.48, 95% CI = 1.02–2.13) and melanoma risk (R = 1.76, 95% CI = 1.23–2.50). Compared to idiopathic PD, LRRK2-G2019S carriers had increased general cancer risks (RR = 1.26, 95% CI = 1.09–1.46), particularly brain (RR = 2.41, 95% CI = 1.06–5.50), breast (RR = 2.57, 95% CI = 1.19–5.58), colon (RR = 1.83, 95% CI = 1.13–2.99), and haematological cancers (RR = 2.05, 95% CI = 1.07–3.92). Female PD patients have decreased general cancer risks compared to male PD patients in this analysis (RR = 0.83, 95% CI = 0.69–0.98).Conclusion: PD patients have reduced risks of colon, rectal, colorectal cancer and lung cancers and increased risks of brain cancer and melanoma. LRRK2-G2019S carriers have increased cancer risks, particularly brain, breast, colon and blood cancers. Female gender was associated with reduced risks. The role of ethnicity, comorbidities, and lifestyle habits on PD patients’ subsequent cancer risk should be further investigated.

In utero exposure to 17α-hydroxyprogesterone caproate and risk of cancer in offspring

17α-hydroxyprogesterone caproate is a synthetic progestogen initially approved in the 1950s to treat gynecologic and obstetrical conditions. Despite continued concerns about safety and short-term efficacy regarding the use of 17α-hydroxyprogesterone caproate for the prevention of preterm birth in pregnant women, little is known about the long-term effects of 17α-hydroxyprogesterone caproate on the health of the offsprings. To examine the association between in utero exposure to17α-hydroxyprogesterone caproate and the risk of cancer in the offspring. The Child Health and Development Studies was a population-based cohort of >18,000 mother-child dyads receiving prenatal care in the Kaiser Foundation Health Plan (Oakland, CA) between 1959 and 1966. Clinical information was abstracted from the mothers' medical records beginning 6 months before pregnancy through delivery. We identified the number and timing of 17α-hydroxyprogesterone caproate injections during pregnancy. Incident cancers diagnosed in the offspring were ascertained through 2019 by linkage to the California Cancer Registry. We used the Cox proportional hazard models to estimate the adjusted hazard ratios and their 95% confidence intervals, with the follow-up time accrued from the date of birth through the date of cancer diagnosis, death, or last contact. A total of 1008 offspring were diagnosed with cancer over 730,817 person-years of follow-up. Approximately 1.0% of the offspring (n=234) were exposed in utero to 17α-hydroxyprogesterone caproate. Exposure in the first trimester was associated with an increased risk of any cancer (adjusted hazard ratio, 2.57; 95% confidence interval, 1.59-4.15), and the risk increased with the number of injections (1-2 injections: adjusted hazard ratio, 1.80; 95% confidence interval, 1.12-2.90; ≥3 injections: adjusted hazard ratio, 3.07; 95% confidence interval, 1.34-7.05). Exposure in the second or third trimester conferred an additional risk for the male (adjusted hazard ratio, 2.59; 95% confidence interval, 1.07-6.28) but not for the female (adjusted hazard ratio, 0.30; 95% confidence interval, 0.04-1.11) offspring. The risk of colorectal (adjusted hazard ratio, 5.51; 95% confidence interval, 1.73-17.59), prostate (adjusted hazard ratio, 5.10; 95% confidence interval, 1.24-21.00), and pediatric brain (adjusted hazard ratio, 34.72; 95% confidence interval, 7.29-164.33) cancer was higher in the offspring first exposed to 17α-hydroxyprogesterone caproate in the first trimester than the offspring not exposed. Caution using 17α-hydroxyprogesterone caproate in early pregnancy is warranted, given the possible link with cancer in the offspring.

Occupational exposure evaluation and radiation protection optimization in coronary angiography procedures

Introduction The large number of coronary angiography procedures and inappropriate use of radiation protection equipment constitute a high occupational radiological risk for cardiologists generated by chronic exposure to low doses of radiation, in particular for parts of the body unprotected such as eyes and head. Materials and methods The eye lens dose was evaluated for seven cardiologists performing coronary angiography procedures over three months. The equivalent dose to the eye lens, Hp (3), was calculated from the equivalent dose to the skin, Hp (0.07), measured by an active dosimeter worn at the cardiologist's neck. The annual eye lens dose and the brain cancer risk were estimated. The correlation between the eye lens dose and the procedure parameters including the dose-area product, the fluoroscopy duration, and the number of fluography images was studied. Phantom-based measurements by a babyline 81 allowed to separate the contribution of the two modes, fluoroscopy and fluorography to the total dose and therefore, to propose another method of continuous lens dose monitoring. Finally, an optimization study was performed to reduce the eye lens dose and consequently the brain cancer risk. Results Two cardiologists have exceeded the annual lens dose limit (28mSv, 22mSv). A good correlation was found between Hp (3) and the fluoroscopy duration (R² = 0.89). The measurements showed that most of the exposure was in fluoroscopic mode (89%). The optimization study reduced the annual eye lens dose to 2.9 mSv and 2.3 mSv, respectively, for these two cardiologists. Thus, this decreased the brain cancer risk by a factor of ten. Conclusion The high eye lens annual doses recorded in this study are due to non-compliance with radiation protection rules. The proposed optimization process reduced the eye lens dose and the risk of brain cancer, at least, by a factor of ten.

Functional Roles and Biological Mechanisms of Circular RNAs and Their Encoded Peptides in Glioma: A Narrative Review

Circular RNAs (circRNAs) are a complicated class of non-coding RNAs that have a covalently closed loop structure and are very stable and cautious. Multiple biological processes of malignancy, including tumorigenesis, development, invasion, metastasis, apoptosis, and vascularization, are disrupted by an increased number of circRNAs. Recent research has showed that circRNAs, functioning as microRNA (miRNA) sponges or protein scaffolds, interacting with RNA-binding proteins (RBPs), and autophagy regulators, affect the transcription and splicing regulation. Many circRNAs have tissue-specific expression patterns and are heavily conserved. CircRNA levels in neurons are dynamically modulated. Growing evidence suggests that circRNAs are highly abundant in neural tissues, perhaps owing to the proliferation of particular genes that promote circularization, implying that circRNA dysregulation is linked to nervous system disorders including glioma. The most widespread and deadly primary malignant brain tumor is glioma. CircRNA has a close connection to glioma, according to reported research. Here, the current knowledge about the properties of circRNAs is introduced and the biological and molecular functions of circRNAs are described. Then, the clinical association of circRNAs with glioma/glioblastoma and their level of expression and their regulatory mechanisms in tumorigenesis are discussed. Moreover, the potential of circRNAs as diagnostic biomarkers and predictors of brain cancer risk and possible therapeutic targets in medicine is examined.

Cancer risk in Parkinson disease: An updated systematic review and meta-analysis.

Increasing evidence suggests significant associations between Parkinson disease (PD) and cancer risks. We conducted an updated review of studies that examined the risks of various cancer among PD patients and how this differed when cancer preceded PD diagnosis or PD diagnosis preceded cancer. Four databases were searched for studies that examined the association between PD and incidence of cancer from database inception to 4 June 2021. Three independent reviewers screened the articles for eligibility and extracted study data. Pooled relative risk with 95% confidence intervals were calculated using a random effects model. Forty studies involving 11 case-control studies, two nested case-control studies, 22 cohort studies, and five cross-sectional studies were included. Compared to controls, PD patients had lower risks of lung, genitourinary, gastrointestinal, and haematological cancers. Conversely, higher risks of melanoma and brain cancer were noted among PD patients. No association was found between PD and risk of female cancers. Subgroup analysis found negative associations between PD patients and risks of colon cancer, rectal cancer, and non-Hodgkin lymphoma. Findings from our meta-analysis suggest PD patients had lower risks of lung, genitourinary, gastrointestinal, and haematological cancers and increased risks of melanoma and brain cancer. Future research to investigate the underlying mechanisms between PD and cancers is warranted.

Farming, Pesticides, and Brain Cancer: A 20-Year Updated Systematic Literature Review and Meta-Analysis.

Simple SummaryA synthesis of 40 years of epidemiologic studies of farming and brain cancer that updates two previous meta-analyses finds that farming with its potential for exposure to chemical pesticides is associated with an increased risk of brain cancer.Twenty additional years of epidemiologic literature have become available since the publication of two meta-analyses on farming and brain cancer in 1998. The current systematic literature review and meta-analysis extends previous research and harmonizes findings. A random effects model was used to calculate meta-effect estimates from 52 studies (51 articles or reports), including 11 additional studies since 1998. Forty of the 52 studies reported positive associations between farming and brain cancer with effect estimates ranging from 1.03 to 6.53. The overall meta-risk estimate was 1.13 (95% CI = 1.06, 1.21), suggesting that farming is associated with a 13% increase in risk of brain cancer morbidity or mortality. Farming among white populations was associated with a higher risk of brain cancer than among non-white populations. Livestock farming (meta-RR = 1.34; 95% CI = 1.18, 1.53) was associated with a greater risk compared with crop farming (meta-RR = 1.13; 95% CI = 0.97, 1.30). Farmers with documented exposure to pesticides had greater than a 20% elevated risk of brain cancer. Despite heterogeneity among studies, we conclude that the synthesis of evidence from 40 years of epidemiologic literature supports an association between brain cancer and farming with its potential for exposure to chemical pesticides.

Cardiorespiratory Fitness And Risk Of Brain Cancer

PURPOSE: Brain cancer although uncommon, leads to significant loss in quality of life due to disability and has a high mortality. While prior studies have revealed the cardiorespiratory fitness (CRF) as a risk factor to cancer incidence, such studies specific to brain cancer does not exist due to its rarity. Since CRF is an objective marker of recent physical activity habits and less prone to misclassification, we aimed to assess the relationship between CRF and risk of brain cancer across age groups in a large (N = 580,559) retrospective study. METHODS: Male (N = 542,104) and female (N = 38,455) US Veterans (age 61.3 ± 9.5) completed a symptom-limited exercise treadmill test (ETT) between 1999-2020. None had a history of brain cancer prior to ETT. We established four CRF categories based on age-specific quartiles of peak metabolic equivalents achieved: Least-Fit (n = 122,905); Low-Fit (n = 202,774); Moderate-Fit (n = 116,390); and High-Fit (n = 138,490). Multivariable Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for brain cancer events across CRF categories. RESULTS: During the follow-up period (median = 8.8 years), 813 individuals (age: 63.3 ± 8.3) developed brain cancer (15 events/100,000 person years of observation) at least one-year post-ETT. After adjustment for age, gender, race, body mass index and smoking, the risk of brain cancer was inversely related to CRF. Brain cancer risk was 7% lower for each 1-MET increase in exercise capacity. When CRF categories were considered, comparisons to the Least-Fit category (referent) revealed that Low-Fit individuals had a 30% lower risk of developing brain cancer (HR 0.70; 95% CI: 0.58-0.83). For Moderate-fit, and High-fit individuals the risk was lower by 33% (HR 0.67; 95% CI: 0.55-0.83); and 38% (HR 0.62; 95% CI: 0.50-0.75), respectively. CONCLUSIONS: We observed an inverse and graded association between CRF and brain cancer incidence. These findings suggest that increased physical activity may provide protection against brain cancer and underscore the importance of promoting physical activity for the public.