Influence of oral hygiene and its interaction with standard of education on the risk of oral cancer in women who neither smoked nor drank alcohol: a hospital-based, case-control study

The association between oral hygiene and head and neck cancer: a meta-analysis

OBJECTIVE

Oral hygiene has been suspected to contribute to the aetiology of head and neck cancer (HNC). Based on the meta-analysis, we evaluated the impact of oral hygiene on head and neck cancer (HNC) and its survival.

MATERIALS AND METHODS

Relevant case-control and cohort studies reporting survival data, oral hygiene data were searched via PubMed, Embase, Cochrane Library, and Web of Science databases. The odds ratios (ORs), hazard ratios (HRs), and 95% confidence intervals (CIs) were used. Subgroup analysis was performed.

RESULTS

Oral hygiene was associated with HNC. Tooth brushing ≥2 a day, dental floss use, denture wearing, caries ≥3, and dental visit ≥1 reduced the risk of oral cavity cancer while mouth wash use, missing teeth >5, gum bleeding, and periodontal disease increased the risk of oral cavity cancer. For oropharynx cancer, tooth brushing ≥2 and caries ≥3 were associated with reduced risk of it. Tooth brushing ≥2 and dental visits ≥1 decreased the risk of pharynx cancer risk and larynx cancer risk, however, missing teeth >5 increased both of them.

CONCLUSION

Oral hygiene was associated with HNC and its sub sites. Oral hygiene should be strengthened, a dental floss use and dentist's visits can be recommended.

Modifiable risk factors for oral cavity cancer in non-smokers: A systematic review and meta-analysis

BACKGROUND

Oral cavity cancer (OCC) is traditionally associated with smoking, but there is an increasing prevalence of the disease among non-smokers. This review investigates possible modifiable risk factors in the development of OCC in non-smokers (OCCNS).

METHODS

PubMed, EMBASE, Web of Science, and Scopus were searched for publications prior to June 2021. Comparative studies investigating modifiable OCCNS risk factors were identified following PRISMA guidelines. Publication date, population size, and results were indexed. Study quality was assessed using MINORS (Methodological Index for Non-Randomized Studies). Factors examined by multiple studies were analyzed using random-effect meta-analysis framework.

RESULTS

Literature search resulted in 1,625 unique publications. 52 records met inclusion criterion, investigating alcohol (n = 22), chewing products (n = 18), diet (n = 7), dental health (n = 11), and medical comorbidities (n = 6).

CONCLUSION

This review demonstrates the paucity of large studies investigating OCCNS risk factors. Further investigation is warranted to help clinicians risk-stratify patients without traditional risk factors.

Association Between Dietary Fatty Acid Pattern and Risk of Oral Cancer

Objective

To investigate the association between dietary fatty acid (FA) patterns and the risk of oral cancer.

Method

A case-control study which included 446 patients with oral cancer and 448 controls subjects was conducted in Southeast China. A structured food frequency questionnaire was used to assess the dietary FA consumption before cancer diagnosis. FA patterns were identified using the principal component analysis, and the relationship between the dietary FA patterns and oral cancer was analyzed by logistic regression.

Results

General differences in FA intake were observed between the patient and control groups. The intakes of saturated FAs (SFAs) C14:0, C16:0, C18:0, and monounsaturated FA C18:1 were higher in the patient group than the control group (p < 0.001). Four FA patterns were derived by principal component analysis. The "SFA" pattern, "Polyunsaturated FA" pattern, "Monounsaturated FA" pattern, and "Medium- and long-chain FA" pattern, which could explain 75.7% of the variance of the dietary FA intake, were submitted to logistic regression analysis. A positive association was observed between the "SFA" pattern and oral cancer risk. Compared with the lowest quartile score, the OR of the highest quartile score was 3.71 (95%CI: 2.31, 5.94, P trend < 0.001) in the multivariate logistic regression model. No significant association was found among the other three patterns and oral cancer risk.

Conclusions

General differences in dietary FA intake were observed between patients with oral cancer and controls. A positive association between the "SFA" pattern and risk of oral cancer was observed after adjusting for potential confounders.

Is There an Interplay between Oral Microbiome, Head and Neck Carcinoma and Radiation-Induced Oral Mucositis?

Head and neck carcinoma is one of the most common human malignancy types and it ranks as the sixth most common cancer worldwide. Nowadays, a great potential of microbiome research is observed in oncology-investigating the effect of oral microbiome in oncogenesis, occurrence of treatment side effects and response to anticancer therapies. The microbiome is a unique collection of microorganisms and their genetic material, interactions and products residing within the mucous membranes. The aim of this paper is to summarize current research on the oral microbiome and its impact on the development of head and neck cancer and radiation-induced oral mucositis. Human microbiome might determine an oncogenic effect by, among other things, inducing chronic inflammatory response, instigating cellular antiapoptotic signals, modulation of anticancer immunity or influencing xenobiotic metabolism. Influence of oral microbiome on radiation-induced oral mucositis is expressed by the production of additional inflammatory cytokines and facilitates progression and aggravation of mucositis. Exacerbated acute radiation reaction and bacterial superinfections lead to the deterioration of the patient's condition and worsening of the quality of life. Simultaneously, positive effects of probiotics on the course of radiation-induced oral mucositis have been observed. Understanding the impact on the emerging acute radiation reaction on the composition of the microflora can be helpful in developing a multifactorial model to forecast the course of radiation-induced oral mucositis. Investigating these processes will allow us to create optimized and personalized preventive measures and treatment aimed at their formation mechanism. Further studies are needed to better establish the structure of the oral microbiome as well as the dynamics of its changes before and after therapy. It will help to expand the understanding of the biological function of commensal and pathogenic oral microbiota in HNC carcinogenesis and the development of radiation-induced oral mucositis.

Characteristics and outcome differences in male and female oral cavity cancer patients in Taiwan

Oral cavity squamous cell carcinoma (OSCC) is a leading cause of death in Taiwan. Most of the patients in the literature are male. The risk factors, cancer characteristics, and treatment outcomes were investigated in female patients and compared with male patients in this study.This retrospective study recruited 2046 OSCC patients between 1995 and 2019. The age, tumor subsites, and survival were reviewed and recorded. Overall survival and disease-free survival were the main outcomes.Female patients represented 6.7% of the entire study cohort. Females were diagnosed at an older age and an earlier local stage than male patients (P < .001). Female patients were less exposed to cigarettes, alcohol, and betel-quid (all P < .001). The tongue (55.1%) was the most frequent subsite in females, while the buccal cavity (38.4%) and the tongue (35.3%) were more likely (P < .001) to be associated with the male gender. Female patients in the tongue cancer subgroup presented less frequently with extra-nodal extension compared with male patients (P = .040). No significant differences in recurrence or overall deaths were observed between the genders during the follow-up period.The OSCC male to female ratio in Taiwan was 14:1. Female OSCC occurred more frequently on the tongue, and was diagnosed at an older age and at an earlier tumor stage than in male patients. No survival difference was found between female and male OSCC patients.

"Fact or fiction?": Oral cavity cancer in nonsmoking, nonalcohol drinking patients as a distinct entity-Scoping review

Oral cavity cancer is often described as a lifestyle-related malignancy due to its strong associations with habitual factors, including tobacco use, heavy alcohol consumption, and betel nut chewing. However, patients with no genetically predisposing conditions who do not indulge in these risk habits are still being encountered, albeit less commonly. The aim of this review is to summarize contemporaneous reports on these nonsmoking, nonalcohol drinking (NSND) patients. We performed database searching to identify relevant studies from January 1, 2000 to March 31, 2021. Twenty-six articles from 20 studies were included in this study. We found that these individuals were mostly females in their eighth decade with tumors involving the tongue and gingivobuccal mucosa. This review also observed that these patients were likely diagnosed with early stage tumors with overexpression of programmed death-ligand 1 (PD-L1) and increased intensity of tumor infiltrating lymphocytes. Treatment response and disease-specific prognosis were largely comparable between NSND and smoking/drinking patients.

A composite oral hygiene score and the risk of oral cancer and its subtypes: a large-scale propensity score-based study

OBJECTIVE

This study aimed to investigate the potential relationship between oral hygiene and the risk of oral cancer and its subtypes after controlling the effects of several confounding factors.

MATERIALS AND METHODS

A large-scale case-control study was conducted from January 2010 to August 2019, recruiting a total of 1,288 oral cancer cases with newly diagnosed and 4,234 healthy controls. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were utilized to minimize confounding effects. Conditional logistic regression was used to evaluate the effects of oral hygiene indicators on oral cancer.

RESULTS

A composite oral hygiene score was developed based on five indicators selected based on PSM and IPTW analysis (including tooth loss, dentures wearing, the frequency of tooth brushing, regular dental visits, and recurrent dental ulcer). Participants with a higher score, compared with their lower counterparts, showed a 49% increased risk (the odds ratio (OR) was 1.49 (95% confidence interval (CI): 1.26-1.75). A similar association pattern was found following IPTW analyses (OR = 1.32; 95% CI: 1.22-1.42). Of note, the adverse effects of poor oral hygiene were more evident among the sites of gingival and buccal (PSM analysis: 2.03-fold and 2.68-fold increased risk; IPTW analysis: 1.57-fold and 2.07-fold increased risk, respectively). Additionally, a greater positive association was observed between poor oral hygiene and oral squamous cell carcinoma, compared with other pathological types.

CONCLUSION

This study establishes a composite oral hygiene score and provides supportive evidence of poor oral hygiene associated with a higher risk of oral cancer, particularly in the gingival and buccal mucosa sites and in the squamous cell carcinoma.

CLINICAL RELEVANCE

The data highlights the importance of improving poor oral hygiene habits, which has public health implications for the prevention of oral cancer.

Toothbrushing frequency and gastric and upper aerodigestive tract cancer risk: A meta-analysis

OBJECTIVE

Results of epidemiological studies evaluating the association between toothbrushing and gastric and upper aerodigestive tract (UADT) cancer risk showed inconsistent results. The purpose of this study was to evaluate the association between toothbrushing and gastric and UADT cancer risk and quantify the dose-response association between them.

METHODS

We searched the PubMed, EMBASE and Cochrane Library databases to identify relevant studies on toothbrushing and gastric and UADT cancer risk. Statistical analyses were performed using STATA 12.0 software.

RESULTS

A total of 30 studies of involving 1 194 017 participants met eligibility criteria and were included in the meta-analysis. Meta-analysis using a random-effect model showed that the high frequency of toothbrushing was associated with significantly reduced risk of gastric and UADT cancers (OR: 0.55, 95% CI 0.46-0.64, P < .05). Our dose-response analysis presented that every increased toothbrushing per day might reduce oral cavity cancer risk by 6%, pharyngeal cancer risk by 11%, laryngeal cancer risk by 3%, oesophageal cancer risk by 6% and gastric cancer risk by 4%.

CONCLUSIONS

This meta-analysis suggested the negative relationship between frequency of toothbrushing and risk of gastric and UADT cancers. Toothbrushing may be a protective factor for gastric and UADT cancers. However, this association must be further validated through large prospective studies.

The Oral Microbiota May Have Influence on Oral Cancer

The oral microbiota plays an important role in the human microbiome and human health, and imbalances between microbes and their hosts can lead to oral and systemic diseases and chronic inflammation, which is usually caused by bacteria and contributes to cancer. There may be a relationship between oral bacteria and oral squamous cell carcinoma (OSCC); however, this relationship has not been thoroughly characterized. Therefore, in this study, we compared the microbiota compositions between tumor sites and opposite normal tissues in buccal mucosal of 50 patients with OSCC using the 16S rDNA sequencing. Richness and diversity of bacteria were significantly higher in tumor sites than in the control tissues. Cancer tissues were enriched in six families (Prevotellaceae, Fusobacteriaceae, Flavobacteriaceae, Lachnospiraceae, Peptostreptococcaceae, and Campylobacteraceae) and 13 genera, including Fusobacterium, Alloprevotella and Porphyromonas. At the species level, the abundances of Fusobacterium nucleatum, Prevotella intermedia, Aggregatibacter segnis, Capnocytophaga leadbetteri, Peptostreptococcus stomatis, and another five species were significantly increased, suggesting a potential association between these bacteria and OSCC. Furthermore, the functional prediction revealed that genes involved in bacterial chemotaxis, flagellar assembly and lipopolysaccharide (LPS) biosynthesis which are associated with various pathological processes, were significantly increased in the OSCC group. Overall, oral bacterial profiles showed significant difference between cancer sites and normal tissue of OSCC patients, which might be onsidered diagnostic markers and treatment targets. Our study has been registered in the Chinese clinical trial registry (ChiCTR1900025253, http://www.chictr.org.cn/index.aspx).

Association between dietary inflammatory index and the risk of oral cancer in the southeast of China

BACKGROUND/OBJECTIVES

To evaluate the role of the potential inflammatory effects of diet using the Energy adjusted Dietary Inflammatory Index (E-DII) for oral cancer.

SUBJECTS/METHODS

A case-control study including 295 oral cancer cases and 425 controls from September 2010 to June 2018 was performed in Fujian Province, China. The E-DII was calculated based on the food frequency questionnaire (FFQ) and adjusted by total energy intake. The association between E-DII and the risk of oral cancer was estimated with unconditional logistic regression model.

RESULTS

Compared with E-DII score in the lowest quartile, those with E-DII score in the fourth quartile were at the higher risk of oral cancer (OR = 2.57; 95% CI: 1.54, 4.29, P_trend = 0.013). When analyses were carried out using E-DII as a continuous variable, one-unit increase in E-DII increased the odds of having oral cancer by 3% (95% CI: 1.00, 1.06). Moreover, there was a significant interaction between the E-DII and oral hygiene for oral cancer (P_interaction < 0.001, in those without and with poor hygiene, the OR (95% CI) were 1.96 (0.96, 4.00) and 4.23 (1.83, 9.81), respectively).

CONCLUSIONS

The present study suggests that the higher E-DII score, indicated a pro-inflammatory diet, may be a risk factor for oral cancer in southeast of China. More large samples and prospective studies need to validate our results and explore the prevention strategies of oral cancer via changing dietary habits.

Assessment of knowledge of oral cancer in dentists in the Los Ríos Region, Chile, in 2017

Objective: To determine the level of knowledge of Oral Cancer (OC) of dental surgeons in Los Rios Region in the year 2017. Materials and methods: A descriptive, cross-sectional study consisting of a survey containing 24 multiple-choice questions was conducted and applied in person to 102 public practice dentists of Los Ríos Region, between March-July 2017. Participants were previously informed that the survey was voluntary, anonymous and confidential. Characterization data from the population was collected and the variable “Knowledge of Oral Cancer” along with its subsections on OC epidemiology, etiopathogenesis, diagnosis, treatment/complications and prognosis/prevention were measured. Tabulated data were analyzed through descriptive statistics. Results were presented through a passing percentage (60% minimum for approval). Results: 100 surveys were answered (with a 98% response rate). Knowledge of OC averaged a 77% passing rate among the participants: 63% for the epidemiology section, 78% for etiopathogenesis, 86.5% for diagnosis, 64% for treatment/complications, while OC prevention resulted in a 75% passing rate. Conclusion: A high percentage of dental surgeons in Los Rios Region demonstrated a satisfactory knowledge of the etiopathogenesis, diagnosis and prevention of OC. However, a low percentage responded correctly regarding the epidemiological factors, treatment and complications. It is highly recommended to follow the same research methodology in other regions across Chile in order to analyze results at a national level with a new approach, so as to properly guide future professional training programs.

Evidence of past dental visits and incidence of head and neck cancers: a systematic review and meta-analysis

BACKGROUND

Regular/frequent dental visits, at least annually, can aid in reducing the public health burden of head and neck cancers (HNCs) by facilitating earlier detection of the disease. The aim of this study was to conduct a quantitative assessment of any independent association between past dental visits/check-ups and incidence of cancers of HN/upper aerodigestive tract (UADT) and oral cavity worldwide.

METHODS

PubMed, CINAHL, and Cochrane databases were searched for all observational studies published until August 2017 in any language that assessed an association of past dental visits/dental check-ups among the incident cases of HNC/UADT cancers. Screening and quality assessment of the articles was performed by two independent reviewers. Three different meta-analyses were conducted: two based on the incident cancer reported in the studies (HNCs/cancers of UADT and oral cavity); another included all studies irrespective of the type of cancer reported with the frequency of past dental visits as subgroups.

RESULTS

Searches retrieved 3164 titles: after removing duplicates, 1377 remained. Of these, 62 were reviewed in full, but only 38 were eligible for inclusion. Under the random effects model, odds of past never/irregular/not frequent dental visits were greater in HNC cases and oral cancer cases as compared to the hospital-based/population-based controls [HNCs-unadjusted odds ratio (OR) 2.24; 95% confidence interval (CI) 1.89 to 2.65) and (oral cancers-OR 1.93; 95% CI 1.47 to 2.52]. Similar results were observed for all cancers with frequency of past dental visits as subgroup analysis (OR 2.01; 95% CI 1.76 to 2.30). Meta-regression findings indicate that none of the subgroup influenced the effect estimates for incidence of cancers. There was no publication bias in our study.

CONCLUSION

This systematic review and meta-analysis indicates that individuals with never/irregular/not frequent dental visits are more likely to be incident cases of HNCs/UADT cancers.

Role of Poor Oral Hygiene in Causation of Oral Cancer-a Review of Literature

Oral squamous cell carcinomas (OSCC) are among the commonest cancers in South East Asia and more so in the Indian subcontinent. The role of tobacco and alcohol in the causation of these cancers is well-documented. Poor oral hygiene (POH) is often seen to co-exist in patients with OSCC. However, the role of poor oral hygiene in the etio-pathogenesis of these cancers is controversial. We decided to evaluate the available literature for evaluating the association of POH with OSCC. A thorough literature search of English-language articles in MEDLINE, PubMed, Cochrane Database of Systematic Reviews, and Web of Science databases was conducted, and 93 relevant articles were short-listed. We found that POH was strongly associated with oral cancers. It aids the carcinogenic potential of other known carcinogens like tobacco and alcohol. Even on adjusting for known confounding factors like tobacco, alcohol use, education, and socio-economic strata, presence of POH exhibits higher odds of developing oral cancer.

Independent and joint effects of tea and milk consumption on oral cancer among non-smokers and non-drinkers: a case-control study in China

This study aims to evaluate the independent and joint effects of tea and milk consumption on oral cancer risk among non-smokers and non-drinkers (NS/ND). A hospital-based case-control study was performed in Fujian, China. 421 cases and frequency-matched 1398 controls were included without tobacco smoking and alcohol drinking habits. Unconditional logistic regression model was used to assess the relationship of tea and milk consumption with oral cancer risk. Tea and milk consumption were significantly associated with decreased risk of oral cancer, the adjusted odds ratios (aORs) were 0.73 (95% CI: 0.54-0.97) and 0.69 (95% CI: 0.55-0.88), respectively. According to subgroup analysis, the inverse associations between tea consumption and oral cancer risk were only observed among the elders (>60 years) and urban residents. While the protect effect of milk drinking was more obvious in males, normal body mass index population (18.5–23.9), urban residents and those age ≤ 60 years. Additionally, a significantly multiplicative interaction between tea and milk consumption was observed for oral cancer risk (P = 0.001). The present study is the first to simultaneously assess the association of tea consumption and milk drinking with oral cancer risk. The results suggest that tea and milk consumption are independent protective factors for oral cancer among NS/ND, with a joint effect between them.

A functional haplotype of NFKB1 influence susceptibility to oral cancer: a population-based and in vitro study

Genetic variations of NF‐κB and its inhibitor IκB genes and their biological mechanism in oral cancer were not well recognized. The purpose of this study was to evaluate the associations of polymorphisms in NFKB1 and NFKBIA with oral cancer susceptibility, and further explore their potential mechanism in vitro. First, the polymorphisms of NFKB1 and NFKBIA were genotyped through iPLEX Sequenom MassARRAY platform in a case–control study with 425 oral cancer patients and 485 healthy controls. Then, the function was explored by a luciferase reporter assay and an electrophoretic mobility shift assay (EMSA) in human tongue squamous cell carcinoma cell lines. The results indicated that NFKB1 rs28362491 Del/Del and rs72696119 G/G genotypes were associated with the risk of oral cancer, with a strong linkage disequilibrium (D′ = 0.991, r² = 0.971). Moreover, DG haplotype of NFKB1 also showed a significant increased risk (OR = 1.25, 95% CI: 1.02–1.53, P = 0.030). Dual‐luciferase reporter assays further revealed that the plasmids with DG or IG or DC haplotype transfected with Tca‐8113 cells or CAL‐27 cells had a lower luciferase expression than that with IC haplotype. EMSA demonstrated that 4‐bp ATTG deletion in the promoter of NFKB1 abolished the binding site of transcription factor. Our preliminary findings suggest that the haplotype of rs28362491 and rs72696119 in NFKB1 could act as a novel genetic marker to predict oral cancer risk in the southeast of China, but much more extensive researches still need to be conducted.

Tooth loss and cancer risk: a dose-response meta analysis of prospective cohort studies

Conflicting results to identify the relationship between tooth loss and cancer risk. Therefore, a dose-response meta-analysis was performed to clarify and quantitative assessed the correlation between tooth loss and cancer risk. Up to March 2017, 25 observational epidemiological studies were included in current meta-analysis. Tooth loss was significantly associated with a higher risk of cancer. Additionally, tooth loss was associated with significantly a higher risk of esophageal cancer, gastric cancer, head and neck cancer, colorectal cancer, pancreas cancer, lung cancer, prostate cancer, bladder cancer and hematopoietic cancer. Subgroup analysis showed consistent findings. Furthermore, a significant dose-response relationship was observed between tooth loss and cancer risk. Increasing per 10 of tooth loss was associated with a 9% increment of cancer risk, 14% increment of esophageal cancer risk, 9% increment of gastric cancer risk, 31% increment of head and neck cancer risk, 4% increment of colorectal cancer risk, 7% increment of pancreas cancer risk, 19% increment of lung cancer risk, 2% increment of bladder cancer risk and 3% increment of hematopoietic cancer risk. Considering these promising results, tooth loss might be harmful for health. Large sample size, different ethnic population and different cancer type are warranted to validate this association.

Differences in modifiable factors of oral squamous cell carcinoma in the upper and lower of oral fissure

The aim of this study was to explore differences in the effects of modifiable factors on oral squamous cell carcinoma (OSCC) occurring in the lower oral fissure (LOF) and upper oral fissure (UOF). We conducted a case-control study with 697 OSCC patients (119 UOF and 578 LOF) and 1910 frequency-matched controls in Fujian province, China. Data on demographic characteristics and possible modifiable factors was collected using a structured questionnaire. Unconditional logistic regression was utilized to calculate the odds ratios (ORs) and corresponding 95% confidence intervals (CIs). Alcohol drinking was more strongly associated with an increased risk of OSCC-LOF than OSCC-UOF. Tobacco smoking, the number of teeth lost ≥5, wearing denture, and recurrent oral ulceration showed similarly associations with OSCC-LOF and -UOF risk. Similarly, the beneficial effects of tea consumption, tooth-brushing ≥2times per day, high intake of fresh fish, seafood, green-leafy vegetables, other vegetables and fruits were not significantly different on OSCC-LOF and -UOF. Although most of the modifiable factors exert similar effects on both OSCC sites, this study suggests that the sites of oral cavity in LOF may be affected more by alcohol drinking than the sites in UOF. Further studies with larger samples are warranted to confirm our findings.

A novel prognostic index for oral squamous cell carcinoma patients with surgically treated

This study aims to develop an applicable prognostic index with conventional factors for predicting outcome of patients with oral squamous cell carcinoma (OSCC). We performed a prospective study in a large cohort of 892 OSCC patients in Fujian, China. All patients were randomly divided into a discovery group and validation group. A prognostic index was developed based on β value of each significant variable obtained from the multivariate Cox regression model. The results from discovery and validation set demonstrated thatthe model-4(included clinical stage, tumor differentiation, ill-fitting denture, oral hygiene and cigarette smoking) was the optimal model. The optimal cutoff points of prognostic index (1.88 and 2.80) were determined by X-tile program which categorized all subjects into low, middle and high risk subsets. Patients in high risk group were at the greatest risk of death compared with those in low risk group (HR: 6.02; 95%CI: 4.33-8.38). Moreover, there was a significant tendency of the worse overall survival with the higher prognostic index (Ptrend <0.001). The discriminatory capacity of prognostic index was 0.661(95%CI: 0.621-0.701). This study developed and validated a prognostic index that is an economical and useful tool for predicting the clinical outcomes of OSCC patients in Southeast China. Future randomized trials with larger cohort are required to confirm our results.