Elucidating the underlying causes of oral cancer through spatial clustering in high-risk areas of Taiwan with a distinct gender ratio of incidence

Factors associated with recurrence in patients with oral cancer in Mongolia

INTRODUCTION

In Mongolia, there has been limited research on the posttreatment survival rate, recurrence, and occurrence of oral cancer. The goal of this study is to investigate the risk factors that contribute to the recurrence of oral cancer to increase survival rates, facilitate early detection, and improve treatment accuracy.

METHOD

A retrospective cohort method was used, with medical records from 173 patients diagnosed with squamous cell carcinoma of the mouth at the National Cancer Center of Mongolia's Department of Head and Neck Surgery, Radio, and Chemotherapy between 2012 and 2017. The Mongolian National University of Medical Sciences' Research Ethics Committee approved the project.

RESULTS

The findings revealed that 109 cases (63.0%) were men and 64 (37.0%) were females, with a large proportion of patients (28.3%) falling between the ages of 61 and 70. Men had a 3.8 times higher risk of cancer recurrence than women (OR = 3.79, CI = 1.24-11.57). Furthermore, lymph node metastases and treatment were linked to oral cancer recurrence.

CONCLUSION

This study offers light on the factors that influence the recurrence of oral cancer, giving useful insights for improving patient outcomes through early detection and proper treatment.

Detecting high-risk neighborhoods and socioeconomic determinants for common oral diseases in Germany

BACKGROUND

Ideally, health services and interventions to improve dental health should be tailored to local target populations. But this is not the standard. Little is known about risk clusters in dental health care and their evaluation based on small-scale, spatial data, particularly among under-represented groups in health surveys. Our study aims to investigate the incidence rates of major oral diseases among privately insured and self-paying individuals in Germany, explore the spatial clustering of these diseases, and evaluate the influence of social determinants on oral disease risk clusters using advanced data analysis techniques, i.e. machine learning.

METHODS

A retrospective cohort study was performed to calculate the age- and sex-standardized incidence rate of oral diseases in a study population of privately insured and self-pay patients in Germany who received dental treatment between 2016 and 2021. This was based on anonymized claims data from BFS health finance, Bertelsmann, Dortmund, Germany. The disease history of individuals was recorded and aggregated at the ZIP code 5 level (n = 8871).

RESULTS

Statistically significant, spatially compact clusters and relative risks (RR) of incidence rates were identified. By linking disease and socioeconomic databases on the ZIP-5 level, local risk models for each disease were estimated based on spatial-neighborhood variables using different machine learning models. We found that dental diseases were spatially clustered among privately insured and self-payer patients in Germany. Incidence rates within clusters were significantly elevated compared to incidence rates outside clusters. The relative risks (RR) for a new dental disease in primary risk clusters were min = 1.3 (irreversible pulpitis; 95%-CI = 1.3-1.3) and max = 2.7 (periodontitis; 95%-CI = 2.6-2.8), depending on the disease. Despite some similarity in the importance of variables from machine learning models across different clusters, each cluster is unique and must be treated as such when addressing oral public health threats.

CONCLUSIONS

Our study analyzed the incidence of major oral diseases in Germany and employed spatial methods to identify and characterize high-risk clusters for targeted interventions. We found that private claims data, combined with a network-based, data-driven approach, can effectively pinpoint areas and factors relevant to oral healthcare, including socioeconomic determinants like income and occupational status. The methodology presented here enables the identification of disease clusters of greatest demand, which would allow implementing more targeted approaches and improve access to quality care where they can have the most impact.

Oral cancer mortality and factors associated in the state of Ceara, Brazil, 2009-2019: a spatial analysis

The study aimed to analyze the spatial distribution and factors associated with oral cancer mortality in the 2009-2019 period in the municipalities of Ceará, Brazil. This ecological study of oral cancer deaths used distribution analysis, autocorrelation, and spatial regression. The oral cancer mortality rate has spatial autocorrelation. In the geographically weighted regression analysis, a negative relationship was observed between mortality and the number of households with access to the sewage system (β = -0.001) and the mean number of people per household (β = -5.947). We observed a positive relationship between mortality and percentage of oral health coverage in Primary Health Care (β = 0.021), number of people living in the rural area of ​​the municipality (β = 0.0001), Municipal Human Development Index (β = 40.417), and aging rate (β = 1.169). We can conclude that the influence on the mortality risk showed spatial clusters that require priority in public policies that impact oral cancer morbimortality.

Modeling transmission of hexavalent chromium concentration and its health cost with a water quality analysis simulation program

In this study, the Water Quality Analysis Simulation Program (WASP7) was used to evaluate the transmission of hexavalent chromium (Cr(VI)) contamination in a water-sediment system and its flux into cultivated soils. The agricultural areas adjacent to the Wu River in Taiwan were taken as the study area, as these soils were heavily polluted with Cr(VI) concentrations of 2173-3271 μg/kg. The rates of accumulation of Cr(VI) are affected by the distance from the source of contamination and the size and type of cultivated areas. The highest concentrations of Cr(VI) (4.27 mg/kg) were detected in soil from Changhua city and correlated with the greater risk of gastric cancer in residents. Specifically, the risk of gastric cancer due to Cr(VI) contamination of agricultural soil was 3 × 10 - 7 - 15.2 × 10 - 6 in Taichung city (upstream) and 1.3 × 10 - 6 - 76.3 × 10 - 6 in Changhua county (downstream). The values of statistical life-years (VSLYs) were US$6.2-10 million for rice, US$42-60 million for corn, and US$360-580 million for other vegetables, respectively, each year. It is critical that techniques other than source reduction are used to reduce human exposure to Cr(VI), such as chemical oxidation or ion-exchange treatment to remove Cr(VI) from factory wastewaters, prior to their discharge into rivers. PRACTITIONER POINTS: This study evaluated the transmission of hexavalent chromium (Cr(VI)) contamination in a water-sediment-soil system. Maximum concentrations of Cr(VI) most rapidly accumulated in the smallest cultivated areas. The highest concentrations of Cr(VI) (3.3 mg/kg) were correlated with the greater risk of gastric cancer. Young children had a threefold greater risk of gastric cancer than adults. Techniques other than source reduction are prior to their discharge into rivers.

Low-dose aspirin confers a survival benefit in patients with pathological advanced-stage oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) remains one of the most challenging clinical problems in the field due to its high rate of locoregional and distant metastases. However, studies that assess the association between aspirin use and survival in patients with OSCC are limited. Moreover, patients that recruited from those studies might have tumors that arose from different anatomic regions of the head and neck, including the oral cavity, oropharynx, etc. Since tumors within these distinct anatomic regions are unique in the context of epidemiology and tumor progression, we sought to evaluate the association of aspirin use with squamous cell carcinomas located within the oral cavity only. In this 10-year cohort study, we evaluated aspirin use and survival rates in relation to clinical characteristics as well as duration of aspirin use in patients with OSCC. Our findings suggest that OSCC patients with aspirin use for more than 180 days showed improved overall and disease-specific survival rates. Aspirin also improves survival in patients across various stages of OSCC. Cox regression models indicated that aspirin use was associated with a good prognosis. In conclusion, this evidence indicates that aspirin may be potentially used as an adjuvant therapy for OSCC.

Oral microbial profile in oral cancer patients before and after radiation therapy in a cancer care center - A prospective study

Background:

Head and neck cancer is the sixth most common cancer reported worldwide. In many cases, the level of aggressiveness of therapy adopted in cancer patients may cause the alteration in oral microbiota; the emergence of potential pathogens may cause opportunistic infections in already immune-compromised individuals leading to increases in morbidity and mortality. Hence, this study was conducted to assess the oral microbial profile in oral cancer patients before and after radiotherapy.

Materials and Methods:

A total of 145 oral swabs were collected before radiotherapy (n = 96), 3 months postradiotherapy (n = 25), 6 months postradiotherapy (n = 12) and controls (n = 12). The samples were inoculated into brain–heart infusion broth and later in different media for bacterial isolation. The isolates were subjected to phenotypic characterization by automatic identification system.

Results:

Among the 96 samples studied from the preradiotherapy patient samples, Streptococcus species (n = 28) were the predominant isolate, followed by Staphylococcus species (n = 16), Enterobacter species (n = 6) and Enterococcus species (n = 6). Of the 25 samples studied 3 months after radiotherapy, Klebsiella pneumoniae (n = 4) was isolated and 12 samples studied after 6 months of radiotherapy Candida species (n = 4) and Pediococcus species (n = 3) were isolated. Among the control group (n = 12) screened, Streptococcus acidominimus (n = 3) is the predominant bacteria isolated.

Conclusion:

High prevalence of Streptococcus sp. was found in patients of oral cancer before radiotherapy, while Candida albicans and Klebsiella species and Pediococcus species are the significant pathogens isolated in postradiotherapy cancer patients.

Evaluation of hexavalent chromium concentration in water and its health risk with a system dynamics model

This study is the first to use reliable data sources to establish a reasonable mass balance of Cr(VI) contamination in river water, sediment, and farmland soil. A system dynamics model was used to establish the interrelationships among water, Cr(VI) contamination, and health effects in the Wu River watershed (between Taichung city and Changhua county) between 2018 and 2048 (30 years). The results show very little Cr(VI) contamination in rivers; most flowed downstream or settled in sediment, and the accumulation of Cr(VI) in the sediment increased throughout the study period. The highest Cr(VI) concentrations in farmland soil (338.46 mg/kg) were reached in Changhua county as a result of greater Cr(VI) contamination from upstream and local factories. This Cr(VI) contamination led to gastric cancer risks of 5.24 × 10^-4 and 4.38 × 10^-6 in Changhua county and Taichung city, respectively. Although most of the Cr(VI) contamination was discharged from Taichung City, greater health risks and losses occurred downstream in Changhua county; medical costs were 55 times higher. For total quality control, a reduction rate of at least 68% should be reached in the study area. These findings will be helpful in predicting the transmission of Cr(VI) contamination over long study periods with a systematic model.

Factors influencing body image in posttreatment oral cavity cancer patients

OBJECTIVE

The purpose of this study of posttreatment oral cavity cancer (OCC) patients was to identify factors associated with self-reported overall body image, perceived attractiveness, and dissatisfaction with body appearance.

METHODS

This cross-sectional study recruited patients with OCC from the outpatient radiation department of a single cancer center in Northern Taiwan. Demographic and clinical characteristics were recorded, and patients were assessed using the Hospital Anxiety and Depression Scale (HADS), the Liebowitz Social Anxiety Scale (LSAS), the University of Washington Quality of Life Scale (UW-QOL), and the Body Image Scale (BIS).

RESULTS

A total of 168 patients were included in this current study, 76 females and 92 males. Negative overall body image was associated with greater degree of depression, greater fear of social interactions, poorer social-emotional function, receipt of surgery, female gender, and greater avoidance of social interaction; these factors explained 49.0% of the variance in this outcome measure. Poor perceived attractiveness was associated with greater depression, greater fear of social interaction, and receipt of surgery; these factors explained 25.4% of the variance in this outcome measure. Dissatisfaction with body appearance was associated with poor social-emotional function, greater fear of social interaction, receipt of reconstruction, advanced cancer stage, and female gender; these factors explained 52.2% of the variance in this outcome measure.

CONCLUSIONS

This study of posttreatment OCC patients indicated that depression and fear of social interaction strongly influenced overall body image, perceived attractiveness, and dissatisfaction with body appearance.

Epidemiologic characteristics of oral cancer: single-center analysis of 4097 patients from the Sun Yat-sen University Cancer Center

Background

Oral cancer is a common type of head and neck cancers. Knowing its epidemiologic characteristics is crucial to preventing, diagnosing, and treating this cancer. This study aimed to explore the epidemiologic characteristics of oral cancer in South China.

Methods

We retrospectively analyzed data from 4097 oral cancer patients treated at the Sun Yat-sen University Cancer Center between 1960 and 2013. We compared the age of onset, sex ratio, pathologic type, and primary tumor location among three subcultural areas (Guangfu, Hakka, and Chaoshan) and between an economically developed region and a less-developed one in Guangdong.

Results

Overall, oral cancer had a male-to-female ratio of approximately 2:1, and this ratio decreased over time. Oral cancer occurred mostly in patients of 45–64 years old (54.5%), and the percentage of older patients gradually increased over time. The most common tumor location was the tongue. Squamous cell carcinoma was the predominant pathologic type. The percentage of blood type O in oral cancer patients was lower than that in the healthy population. The male-to-female ratio in the Chaoshan area was higher than that in the Guangfu and Hakka areas, whereas the age of disease onset in Guangfu was higher than that in Hakka and Chaoshan. The male-to-female ratio was lower and the age of disease onset was higher in the economically developed region than in the less-developed region.

Conclusion

The incidence of oral cancer in South China presents typical characteristics to which doctors should pay attention when diagnosing and treating oral cancer patients.

Type 2 diabetes mellitus and risk of oral cancer and precancerous lesions: a meta-analysis of observational studies

OBJECTIVE

Associations between type 2 diabetes mellitus (type 2 DM) and risk of oral cancer and precancerous lesions have been reported with controversial findings. We performed a meta-analysis to explore these associations.

METHODS

We identified studies by a literature search of MEDLINE and EMBASE through May 31, 2014, and by searching the reference lists of pertinent articles. Summary relative risk (SRR) with 95% confidence interval (CI) was calculated with a random-effects model. Between- study heterogeneity was assessed using the Cochran's Q and I(2) statistics.

RESULTS

A total of 13 studies (4 case-control and 9 cohort studies) on the association between type 2 DM and oral cancer were included. Overall analysis found that compared with non-diabetic individuals, individuals with type 2 DM had a significantly elevated incidence of oral cancer (SRR=1.15, 95% CI: 1.02-1.29; Pheterogeneity=0.277, I(2)=15.4%; 10 studies). Subgroup analyses found that duration of follow-up (⩾11years) significantly altered this positive association. Type 2 DM was associated with increased oral cancer mortality (SRR=1.41, 95% CI: 1.16-1.72; 4 studies). Meta-analysis of the four case-control studies showed a positive association between type 2 DM and risk of oral precancerous lesions (SRR=1.85, 95%CI: 1.23-2.80; Pheterogeneity=0.038, I(2)=57.5%). No significant public bias was found across these studies.

CONCLUSIONS

These findings of this meta-analysis indicate that compared with non-diabetic individuals, individuals with type 2 DM have an elevated risk of oral cancer and precancerous lesions development.

Epidemiology of oral cancer in Asia in the past decade--an update (2000-2012)

The prevalence of oral cancers (OC) is high in Asian countries, especially in South and Southeast Asia. Asian distinct cultural practices such as betel-quid chewing, and varying patterns of tobacco and alcohol use are important risk factors that predispose to cancer of the oral cavity. The aim of this review is to provide an update on epidemiology of OC between 2000 and 2012. A literature search for this review was conducted on Medline for articles on OC from Asian countries. Some of the articles were also hand searched using Google. High incidence rates were reported from developing nations like India, Pakistan, Bangladesh, Taiwan and Sri Lanka. While an increasing trend has been observed in Pakistan, Taiwan and Thailand, a decreasing trend is seen in Philippines and Sri Lanka. The mean age of occurrence of cancer in different parts of oral cavity is usually between 51-55 years in most countries. The tongue is the leading site among oral cancers in India. The next most common sites in Asian countries include the buccal mucosa and gingiva. The 5 year survival rate has been low for OC, despite improvements in diagnosis and treatment. Tobacco chewing, smoking and alcohol are the main reasons for the increasing incidence rates. Low socioeconomic status and diet low in nutritional value lacking vegetables and fruits contribute towards the risk. In addition, viral infections, such as HPV and poor oral hygiene, are other important risk factors. Hence, it is important to control OC by screening for early diagnosis and controlling tobacco and alcohol use. It is also necessary to have cancer surveillance at the national-level to collect and utilise data for cancer prevention and control programs.

Geospatial disparities and the underlying causes of major cancers for women in Taiwan

Some specific types of cancer still pose a severe threat to the health of Taiwanese women. This study focuses on determining the geographical locations of hot spots and causal factors related to the major categories of cancers in Taiwanese women. Cancer mortality data from 1972 to 2001 of 346 townships in Taiwan were obtained from the Atlas of Cancer Mortality. Principal component analysis was conducted to determine the primary categories of female cancers. The spatial patterns of hot spots and cold spots for each major cancer category were identified using the local indicator of spatial association. Finally, the regional differences between the hot spots and cold spots were compared to confirm the possible factors causing cancer throughout Taiwan. A total of 21 cancer types in women were divided into seven major categories, which accounted for 68.0% of the total variance. The results from the spatial autocorrelation analysis showed significant spatial clusters of the cancer categories. Based on the overall consistency of results between this study and those of previous research, this study further identified the high-risk locations and some specific risk factors for major cancer types among Taiwanese women.

Assessing and mapping spatial associations among oral cancer mortality rates, concentrations of heavy metals in soil, and land use types based on multiple scale data

In this study, a deconvolution procedure was used to create a variogram of oral cancer (OC) rates. Based on the variogram, area-to-point (ATP) Poisson kriging and p-field simulation were used to downscale and simulate, respectively, the OC rate data for Taiwan from the district scale to a 1 km × 1 km grid scale. Local cluster analysis (LCA) of OC mortality rates was then performed to identify OC mortality rate hot spots based on the downscaled and the p-field-simulated OC mortality maps. The relationship between OC mortality and land use was studied by overlapping the maps of the downscaled OC mortality, the LCA results, and the land uses. One thousand simulations were performed to quantify local and spatial uncertainties in the LCA to identify OC mortality hot spots. The scatter plots and Spearman’s rank correlation yielded the relationship between OC mortality and concentrations of the seven metals in the 1 km cell grid. The correlation analysis results for the 1 km scale revealed a weak correlation between OC mortality rate and concentrations of the seven studied heavy metals in soil. Accordingly, the heavy metal concentrations in soil are not major determinants of OC mortality rates at the 1 km scale at which soils were sampled. The LCA statistical results for local indicator of spatial association (LISA) revealed that the sites with high probability of high-high (high value surrounded by high values) OC mortality at the 1 km grid scale were clustered in southern, eastern, and mid-western Taiwan. The number of such sites was also significantly higher on agricultural land and in urban regions than on land with other uses. The proposed approach can be used to downscale and evaluate uncertainty in mortality data from a coarse scale to a fine scale at which useful additional information can be obtained for assessing and managing land use and risk.

Risk of laryngeal and nasopharyngeal cancer associated with arsenic and cadmium in the Tunisian population

Chronic exposure to heavy metals has long been recognized as being capable of increasing head and neck cancer (HNC) incidence, such as laryngeal (LC) and nasopharyngeal (NPC), among exposed human populations. The aim of the present study was to evaluate the concentrations of arsenic (As) and cadmium (Cd) in the blood of 145 patients (LC and NPC) and 351 controls in order to establish a potential relationship between these factors and the occurrence of LC and NPC. Mean blood levels of As and Cd in patients (5.67 and 3.51 μg/L, respectively) were significantly higher than those of controls (1.57 and 0.74 μg/L, respectively). The blood levels of As and Cd were mostly significantly higher than those of controls (p<0.05) after controlling the other risk factors of HNC including tobacco smoking and chewing, and alcohol drinking. Cd levels in blood increase significantly with the number of occupational exposure years for patients (p<0.05). However, seafood was not found to be contributing as an exposure source. Among these risk factors, smoking (>30 pack years) and occupational exposure (>20 years) presented the most significant association with HNC (OR=10.22 and 10.38, respectively, p<0.001). Cd level in blood sample of cases that are occupationally exposed/tobacco users (smokers and chewers) were higher than that of non-occupationally exposed/nontobacco users (p<0.001). The logistic regression model illustrated that HNC (LC+NPC) was significantly associated with blood levels of As (OR=2.41, p<0.001) and Cd (OR=4.95, p<0.001).

Blood nickel and chromium levels in association with smoking and occupational exposure among head and neck cancer patients in Tunisia

Chronic exposure to chromium (Cr) and nickel (Ni) has long been recognized as being capable to increase head and neck cancer (HNC) incidence among exposed human populations. This study represents the first biomonitoring of Cr and Ni exposure in Tunisia and focuses on a possible association with HNC risk. The aim of the present study was to evaluate the concentrations of Cr and Ni in the blood of HNC patients and controls. Metals blood levels of 169 HNC patients and 351 controls were determined using a Perkin-Elmer Analyst 800 Atomic Absorption Spectrometer. Mean blood levels of Cr and Ni in HNC cases (52.15 and 111.60 μg/L, respectively) were significantly higher than those of controls (37.04 and 30.50 μg/L, respectively). Cases' blood levels of Cr and Ni were significantly higher than those of controls after controlling for the other risk factors of HNC, including smoking, shisha consumption, occupational exposure, and nearby environment (P<0.05). Among these risk factors, smoking and occupational exposure presented the most significant association with HNC (odds ratio (OR)=6.54 and 7.66, respectively, P<0.001). Cr and Ni levels in blood sample of cases and controls that are smoker/occupationally exposed were higher than that of non-smoker/non-occupationally exposed (P<0.05). Smokers who are occupationally exposed present the most significant association with HNC (OR=25.08, P<0.0001). High levels of blood Cr (OR=2.09) and high levels of blood Ni (OR=8.87) were strongly associated with HNC after other potential confounders were controlled (P=0.004 and P<0.0001, respectively). This study suggested a potential role of Cr and Ni in the mechanism of HNC development.

Arsenic exposure and oral cavity lesions in Bangladesh

OBJECTIVE

To evaluate the relationship between arsenic exposure and oral cavity lesions among an arsenic-exposed population in Bangladesh.

METHODS

We carried out an analysis utilizing the baseline data of the Health Effects of Arsenic Exposure Longitudinal Study, which is an ongoing population-based cohort study to investigate health outcomes associated with arsenic exposure via drinking water in Araihazar, Bangladesh. We used multinomial regression models to estimate the risk of oral cavity lesions.

RESULTS

Participants with high urinary arsenic levels (286.1 to 5000.0 μg/g) were more likely to develop arsenical lesions of the gums (multinomial odds ratio = 2.90; 95% confidence interval, 1.11 to 7.54), and tongue (multinomial odds ratio = 2.79; 95% confidence interval, 1.51 to 5.15), compared with those with urinary arsenic levels of 7.0 to 134.0 μg/g.

CONCLUSIONS

Higher level of arsenic exposure was positively associated with increased arsenical lesions of the gums and tongue.

Connective tissue growth factor activates pluripotency genes and mesenchymal-epithelial transition in head and neck cancer cells

The epithelial-mesenchymal transition (EMT) is a key mechanism in both embryonic development and cancer metastasis. The EMT introduces stem-like properties to cancer cells. However, during somatic cell reprogramming, mesenchymal-epithelial transition (MET), the reverse process of EMT, is a crucial step toward pluripotency. Connective tissue growth factor (CTGF) is a multifunctional secreted protein that acts as either an oncoprotein or a tumor suppressor among different cancers. Here, we show that in head and neck squamous cell carcinoma (HNSCC), CTGF promotes the MET and reduces invasiveness. Moreover, we found that CTGF enhances the stem-like properties of HNSCC cells and increases the expression of multiple pluripotency genes. Mechanistic studies showed that CTGF induces c-Jun expression through αvβ3 integrin and that c-Jun directly activates the transcription of the pluripotency genes NANOG, SOX2, and POU5F1. Knockdown of CTGF in TW2.6 cells was shown to reduce tumor formation and attenuate E-cadherin expression in xenotransplanted tumors. In HNSCC patient samples, CTGF expression was positively correlated with the levels of CDH1, NANOG, SOX2, and POU5F1. Coexpression of CTGF and the pluripotency genes was found to be associated with a worse prognosis. These findings are valuable in elucidating the interplay between epithelial plasticity and stem-like properties during cancer progression and provide useful information for developing a novel classification system and therapeutic strategies for HNSCC.

Epigenetic regulation of the X-linked tumour suppressors BEX1 and LDOC1 in oral squamous cell carcinoma

The strong associations between oral squamous cell carcinoma (OSCC) and dietary habits such as alcohol consumption (A), betel quid chewing (B) and cigarette smoking (C) and its predominance in men have been well documented; however, systemic analysis of OSCC is limited. Our study applied high-throughput screening methods to identify causative epigenetic targets in a cohort of men with ABC-associated OSCC. We identified BEX1 and LDOC1 as two epigenetically silenced X-linked tumour suppressors and demonstrated a functional link between the transcription of BEX1 and LDOC1 and promoter hypermethylation. Methylation of the BEX1 and LDOC1 promoters was associated significantly (p < 0.0001) with OSCC and were detected in 75% (42/56) and 89% (50/56) of the samples, respectively. We observed concordant increases in the methylation of both genes in 71% (40/56) of the tumours, and potent in vitro and in vivo growth inhibitory effects in OSCC cells ectopically expressing BEX1 and/or LDOC1. Restored expression of BEX1 and LDOC1 suppressed the nuclear factor-κB (NF-κB) signalling pathway, which is the most frequently hyperactivated signalling pathway in OSCC. This suppression might result from decreased p50 and p65 expression. These findings suggest that silencing of BEX1 and LDOC1 by promoter hypermethylation might represent a critical event in the molecular pathogenesis of OSCC and account for the oncogenic effects of ABC exposure and the male predominance of OSCC occurrence. Microarray data are available in the Gene Expression Omnibus (GEO; http://www.ncbi.nlm.nih.gov/geo/)

Oral cancer in Taiwan: is diabetes a risk factor?

OBJECTIVES

The association between diabetes and oral cancer is rarely studied. We investigated the trends of oral cancer in the Taiwanese general population and the possible link with diabetes.

MATERIALS AND METHODS

The trend of age-standardized oral cancer incidence in 1979-2007 in Taiwan was calculated from the Taiwan Cancer Registry database. A total of 494,817 men and 503,723 women without oral cancer from a random sample of 1,000,000 individuals covered by the National Health Insurance were followed up from 2003 to 2005. Cox regression evaluated the adjusted relative risk considering potential detection bias and covariates.

RESULTS

The trends increased significantly in both sexes. Diabetic patients had a higher chance of oral cancer detection because they more frequently visited related medical professionals. Although diabetes status and duration were significantly associated with oral cancer in unadjusted models, none was significant after multivariable adjustment. For comorbidities, chronic obstructive pulmonary disease (a surrogate for smoking) and alcohol-related diagnoses were significant for men, and hypertension and alcohol-related diagnoses were significant for women. Additionally, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and insulin were significant with relative risk (95 % confidence interval) of 1.642 (1.174-2.295) and 2.136 (1.003-4.547), respectively, in men.

CONCLUSIONS

Oral cancer is increasing in Taiwan. Diabetes is not a risk factor after multivariable adjustment.

CLINICAL RELEVANCE

The increasing trend of oral cancer may not be ascribed to diabetes. The association between oral cancer and some comorbidities and medications requires confirmation and may provide strategies for the prevention of oral cancer.

A critical exploration of blood and environmental chromium concentration among oral cancer patients in an oral cancer prevalent area of Taiwan

The growing incidence of oral cancer (OC) in Taiwan has become a crucial public health concern. In particular, Changhua, a county in central Taiwan, carries persistently high OC incidence rate, with an alarmingly high male/female ratio of OC incidence. Previous epidemiological studies had found that the incidence is spatially correlated with the level of soil content to certain heavy metals in the central Taiwan area. Soil and the human body both intake environmental heavy metals, which can be absorbed through various ways. The soil metal concentration is an index of possible environmental exposure to heavy metal, and the blood metal concentration somewhat reflects the level of the exposure on the human body. Metallic carcinogen is likely to generate free radicals and play a role in many cancers, and many studies had reported that environmental exposure to heavy metals is an important risk factor for developing cancer. Studies on animals showed that chronic intake of chromium (Cr) could induce OC. This study aims to explore the association between the Cr concentration in the farm soil and in the blood of OC patients. We recruited 79 OC patients from Changhua County, with their lifestyle being adjusted in regression analysis. The results showed that the Cr concentration in the blood of OC patients is significantly higher than the background value, and is positively associated with the Cr concentration in the soil surrounding their residence (p-value < 0.023). Because Changhua County is only with moderate prevalence of the known OC habitual risk factors, an environmental factor related to heavy metal Cr exposure is suspected. Future investigations may verify the causal relation between Cr and OC.

Possible association between nickel and chromium and oral cancer: a case-control study in central Taiwan

Oral cancer is one of the most common cancers in Taiwan. Changhua County, in central Taiwan, has an extremely high prevalence of oral cancer, along with a high concentration of metal-related industries and soil metal contamination. The aim of this study was to clarify the possible association between metals and oral cancer within this specific area. This study recruited 101 oral cancer patients and 104 controls from the Changhua Christian Hospital. All subjects completed a questionnaire that asked about demographic information; cigarette, alcohol, and betel quid use; and environmental and occupational exposure history. Blood samples were collected and tested for metal concentrations with inductively coupled plasma mass spectrometry. A multiple logistic regression model illustrated that oral cancer was significantly associated with the blood levels of nickel and chromium (both with P<0.0001) after controlling for potential confounders. This study suggested a potential role of these two metals in the mechanism of oral cancer development.

Spatiotemporal trends in oral cancer mortality and potential risks associated with heavy metal content in Taiwan soil

Central and Eastern Taiwan have alarmingly high oral cancer (OC) mortality rates, however, the effect of lifestyle factors such as betel chewing cannot fully explain the observed high-risk. Elevated concentrations of heavy metals in the soil reflect somewhat the levels of exposure to the human body, which may promote cancer development in local residents. This study assesses the space-time distribution of OC mortality in Taiwan, and its association with prime factors leading to soil heavy metal content. The current research obtained OC mortality data from the Atlas of Cancer Mortality in Taiwan, 1972-2001, and derived soil heavy metals content data from a nationwide survey carried out by ROCEPA in 1985. The exploratory data analyses showed that OC mortality rates in both genders had high spatial autocorrelation (Moran's I = 0.6716 and 0.6318 for males and females). Factor analyses revealed three common factors (CFs) representing the major pattern of soil pollution in Taiwan. The results for Spatial Lag Models (SLM) showed that CF1 (Cr, Cu, Ni, and Zn) was most spatially related to male OC mortality which implicates that some metals in CF1 might play as promoters in OC etiology.