Oral status, oral infections and some lifestyle factors as risk factors for oral and oropharyngeal squamous cell carcinoma. A population-based case-control study in southern Sweden

A study of risk factors associated with the presence of oral potentially malignant disorders: a community-based study from Northeastern Thailand

BACKGROUND

The principal objective of this study is to ascertain the connections between well-known risk factors of oral cancer, including smoking (cigarette and tobacco), alcohol consumption, betel quid chewing, irritations in the oral cavity, history of head and neck cancer, and history of working outdoor more than 4 days/week, and the presence of OPMDs within the Thai population.

METHOD

349,318 subjects were recruited for initial screening, then 1,483 subjects who had at least 1 risk factor and a suspicious lesion underwent comprehensive oral examinations followed by a clinical diagnosis and then received initial treatment from either oral surgeons or oral medicine specialists. Among these subjects, individuals with at least 1 risk factor and with a clinical diagnosis of OPMDs were classified as cases, while those with at least 1 risk factor but without OPMDs were categorized as controls. The case group comprised a total of 487 subjects, whereas the control group consisted of 996 subjects. Exclusion criteria were known cases of currently having oral cancer or OPMDs.

RESULTS

The outcomes of the multivariate analysis revealed that among the variables assessed, betel quid (adjusted OR 5.12 [3.93-6.68], p < 0.001) and smoking (adjusted OR 1.46 [1.08-1.97], p = 0.013), there were an association with the presence of OPMDs. Conversely, alcohol drinking, having irritations in the oral cavity, a history of head and neck cancer, and a history of working outdoors more than 4 days/week were not associated with the presence of OPMDs. Furthermore, we also study the synergistic effect of alcohol drinking, irritations in the oral cavity, history of head and neck cancer, and history of working outdoors more than 4 days/week using subgroup analysis. The analysis showed that alcohol consumption combined with smoking or betel quid chewing expressed a significantly increased risk of OPMDs, from 1.46 to 2.03 (OR 2.03 [1.16-3.56], p = 0.014) and from 5.12 to 7.20 (OR 7.20 [3.96-13.09], p < 0.001).

CONCLUSION

Smoking and exposure to betel quid were a significant risk factors for the presence of OPMDs. The combination of alcohol with smoking or betel quid chewing was also found to increase the risk of OPMDs in this Thai northeastern population.

Oral microbial dysbiosis in patients with oral cavity cancers

OBJECTIVES

The pathogenesis of oral cavity cancers is complex. We tested the hypothesis that oral microbiota dysbiosis is associated with oral cavity cancer.

MATERIALS AND METHODS

Patients with primary oral cavity cancer who met the inclusion and exclusion criteria were included in the study. Matching healthy individuals were recruited as controls. Data on socio-demographic and behavioral factors, self-reported periodontal measures and habits, and current dental status were collected using a structured questionnaire and periodontal chartings. In addition to self-reported oral health measures, each participant received a standard and detailed clinical examination. DNA was extracted from saliva samples from patients and healthy controls. Next-generation sequencing was performed by targeting V3-V4 gene regions of the 16 S rRNA with subsequent bioinformatic analyses.

RESULTS

Patients with oral cavity cancers had a lower quality of oral health than healthy controls. Proteobacteria, Aggregatibacter, Haemophilus, and Neisseria decreased, while Firmicutes, Bacteroidetes, Actinobacteria, Lactobacillus, Gemella, and Fusobacteria increased in oral cancer patients. At the species level, C. durum, L. umeaens, N. subflava, A. massiliensis, and V. dispar were significantly lower, while G. haemolysans was significantly increased (p < 0.05). Major periodontopathogens associated with periodontal disease (P. gingivalis and F.nucleatum) increased 6.5- and 2.8-fold, respectively.

CONCLUSION

These data suggested that patients with oral cancer had worse oral health conditions and a distinct oral microbiome composition that is affected by personal daily habits and may be associated with the pathogenicity of the disease and interspecies interactions.

CLINICAL RELEVANCE

This paper demonstrates the link between oral bacteria and oral cancers, identifying mechanistic interactions between species of oral microbiome.

Periodontitis and the risk of oral cancer: a meta-analysis of case-control studies

OBJECTIVE

The current studies have yielded inconclusive findings regarding the connection between periodontitis  and oral cancer (OC). Therefore, our goal is to elucidate this relationship.

MATERIALS AND METHODS

We conducted a thorough search of electronic databases (EMBASE, PubMed, Web of Science, and Cochrane Library) up to September 2023. The Newcastle-Ottawa Scale (NOS) was applied to assess study quality. To evaluate potential publication bias, both a funnel plot and Egger's test were employed. Additionally, a sensitivity analysis was conducted to explore the source of heterogeneity when the I2 statistic exceeded 50%.

RESULTS

This systematic review encompassed 16 studies, involving a total of 6,032 OC patients and 7,432 healthy controls. Our meta-analysis, incorporating data from nine studies, revealed a significant correlation between periodontitis and the risk of OC (OR [odds ratio] = 2.94, 95% CI [confidence interval] (2.13, 4.07); five studies, 6,927 participants; low certainty of evidence). Findings also suggested that individuals with more than 15 missing teeth may have a heightened risk of OC (OR = 1.91, 95% CI (1.01, 3.62)). Furthermore, clinical attachment loss (CAL) and decayed, missing, and filled teeth (DMFT) in OC patients were more pronounced compared to the control group (CAL, SMD = 1.94, 95% CI (0.22, 3.66); DMFT, SMD = 0.65, 95% CI (0.12, 1.18)).

CONCLUSION

Periodontitis may serve as a potential risk factor for OC. However, caution is warranted in interpreting these findings due to the substantial level of heterogeneity.

Poor Dental Health as a Risk Factor for Alveolar Ridge Malignancies

OBJECTIVE

To determine the association between poor dental health and risk of oral cavity squamous cell cancer (OCSCC) at individual tumor subsites.

STUDY DESIGN

Case-control and cross-sectional METHODS: A case-control study was performed using a population-based cohort in North Carolina (Carolina Head and Neck Cancer Epidemiology Study [CHANCE]). A secondary cross-sectional analysis was performed with an institutional cohort (WashU/Siteman). Cases were adults with primary OCSCC and an identifiable tumor subsite. In the CHANCE cohort, controls were adults without head and neck cancer. In the Washington University/Siteman cohort, patients with tongue cancer served as the comparator group. We used number of missing teeth (categorized 0-6, 7-24, 25-28) as a surrogate for poor dental health, which was self-reported in CHANCE and measured on a pretreatment computed tomography scan in the WashU/Siteman study. Adjusted odds ratios (aORs) for missing teeth were estimated for each tumor subsite using binomial logistic regression models.

RESULTS

Near complete tooth loss (25-28 teeth) was associated with a 3.5-fold increased risk of alveolar ridge malignancy (aOR: 3.51; 95% confidence interval [CI]: 1.14-11.01, P = .03) in the CHANCE study. This association was confirmed in our cross-sectional analysis (WashU/Siteman study) where missing 25-28 teeth was associated with an increased risk of alveolar ridge compared to tongue cancer (aOR: 4.60; 95% CI: 1.97-11.10, P = .001).

CONCLUSIONS

This study suggests an association between poor dental health and risk of alveolar ridge cancer independent of smoking, alcohol use, age, race, and sex. Future prospective and translational studies are needed to confirm this association and elucidate the mechanism of dental disease in alveolar ridge malignancies.

Human Papilloma Virus Positive Oropharyngeal Squamous Cell Carcinoma and the Immune System: Pathogenesis, Immunotherapy and Future Perspectives

Oropharyngeal squamous cell carcinoma (OPSCC), a subset of head and neck squamous cell carcinoma (HNSCC), involves the palatine tonsils, soft palate, base of tongue, and uvula, with the ability to spread to adjacent subsites. Personalized treatment strategies for Human Papillomavirus-associated squamous cell carcinoma of the oropharynx (HPV+OPSCC) are yet to be established. In this article, we summarise our current understanding of the pathogenesis of HPV+OPSCC, the intrinsic role of the immune system, current ICI clinical trials, and the potential role of small molecule immunotherapy in HPV+OPSCC.

Alveolar bone loss and tooth loss contribute to increase in cancer mortality among older patients

BACKGROUND

Both cancer and periodontitis are more prevalent with age. Information on their relationship in older patients is limited. This study aims to examine whether periodontitis is associated with increased risk of cancer mortality with a ≥ 75-year age group cohort.

METHODS

A retrospective cohort study was conducted on 1146 patients who had digital radiographic examinations. Alveolar bone loss and loss of teeth were measured as indicators of periodontitis. Hazard ratio (HR) with 95% confidence interval (CI) were taken as the effect size to summarize the associations between periodontitis and risks of cancer mortality using the multivariate adjusted cox proportional hazards model and competing risk hazard model.

RESULTS

Totally, 104 total cancer, 28 lip, oral cavity and pharynx (LOP) cancer, 39 digestive cancer and 13 respiratory cancer cases were documented over 10 years of follow-up. Total cancer (HR 1.27, 95% CI 1.06-1.53) displayed statistically significant associations with alveolar bone loss and tooth loss after adjusting for relevant confounding variables. We also observed borderline significant association between alveolar bone loss and LOP cancer (HR 1.45, 95% CI 0.99-2.12). The above associations were consistent with the results observed from the competing risk hazard models.

CONCLUSION

Our results indicate that older patients suffering from tooth loss or alveolar bone loss are at increased risks of cancer mortality, especially for total cancer and LOP cancer.

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.

Is High-Risk Sexual Behavior a Risk Factor for Oropharyngeal Cancer?

(1) Background: Several lines of evidence established a link between high-risk (HR) sexual behavior (SB), the persistence of human papillomavirus (HPV) DNA in saliva, and the presence of oncogenic HR-HPV subtypes in oropharyngeal squamous cell carcinoma (OPSCC). A highly influential case-control study by D'Souza et al. comparing OPSCC patients and ENT patients with benign diseases (hospital controls) established HR-SB as a putative etiological risk factor for OPSCC. Aiming to replicate their findings in a nested case-control study of OPSCC patients and propensity score (PS)-matched unaffected controls from a large population-based German cohort study, we here demonstrate discrepant findings regarding HR-SB in OPSCC. (2) Methods: According to the main risk factors for HNSCC (age, sex, tobacco smoking, and alcohol consumption) PS-matched healthy controls invited from the population-based cohort study LIFE and HNSCC (including OPSCC) patients underwent interviews, using AUDIT and Fagerström, as well as questionnaires asking for SB categories as published. Afterwards, by newly calculating PSs for the same four risk factors, we matched each OPSCC patient with two healthy controls and compared responses utilizing chi-squared tests and logistic regression. (3) Results: The HNSCC patients and controls showed significant differences in sex distribution, chronologic age, tobacco-smoking history (pack years), and alcohol dependence (based on AUDIT score). However, PS-matching decreased the differences between OPSCC patients and controls substantially. Despite confirming that OPSCC patients were more likely to self-report their first sexual intercourse before age 18, we found no association between OPSCC and HR-SB, neither for practicing oral-sex, having an increased number of oral- or vaginal-sex partners, nor for having casual sex or having any sexually transmitted disease. (4) Conclusions: Our data, by showing a low prevalence of HR-SB in OPSCC patients, confirm findings from other European studies that differ substantially from North American case-control studies. HR-SB alone may not add excess risk for developing OPSCC.

Is Systemic Immunosuppression a Risk Factor for Oral Cancer? A Systematic Review and Meta-Analysis

Even if the relationship between immunosuppression and increased incidence of systemic cancers is well known, there is less awareness about the risk of developing oral cancer in immunosuppressed patients. The aim of this review was to evaluate the association between immunosuppression and the development of oral cancer. Two authors independently and, in duplicate, conducted a systematic literature review of international journals and electronic databases (MEDLINE via OVID, Scopus, and Web of Science) from their inception to 28 April 2023. The assessment of risk of bias and overall quality of evidence was performed using the Newcastle-Ottawa Scale and GRADE system. A total of 2843 articles was identified, of which 44 met the inclusion criteria and were included in either the qualitative or quantitative analysis. The methodological quality of the included studies was generally high or moderate. The quantitative analysis of the studies revealed that immunosuppression should be considered a risk factor for the development of oral cancer, with a percentage of increased risk ranging from 0.2% to 1% (95% CI: 0.2% to 1.4%). In conclusion, the results suggest that a constant and accurate follow-up should be reserved for all immunosuppressed patients as a crucial strategy to intercept lesions that have an increased potential to evolve into oral cancer.

A Systematic Review and Meta-Analysis Assessing the Role of Oral Health as a Risk Factor in Oral Cancer

Oral squamous cell carcinoma is the leading type of cancer in Southeast Asian countries and many parts of the world. Many factors increase the risk of oral cancer, like tobacco, betel nuts, alcohol consumption, sharp teeth, infections, and other factors. Oral health-related issues have been reported in many studies of oral cancer, but there is a need to understand the role of the same as a risk factor. The systematic review and meta-analysis were conducted to assess the role of oral health as a risk factor in oral cancer. The population diagnosed with oral cancer (P) of all age groups and both gender, exposure (E) is oral health (includes poor oral hygiene, periodontal disease, and other oral diseases excluding oral potentially malignant disorders (OPMD)), the comparator (C), is patients without oral health issues, outcome (O) is the role of poor oral health as a risk factor for oral cancer. A systematic review and meta-analysis were conducted. The databases used for the search were PubMed, Cochrane Database, Embase, Scopus, and Google Scholar. The unpublished reports, reviews, and grey literature were considered. Case-control studies were included assessing poor oral health as a risk factor with odds ratio as an effective measure. Newcastle Ottawa Scale for risk of bias in the case-control study was considered. The study results showed that tooth loss odds ratio (OR)=1.13, CI (0.99-1.26), I² value of 71.7%, Oral hygiene OR=1.29, CI (1.04-1.54), I² value of 19.7% and in periodontal diseases OR=2.14 CI (1.70-2.58), I² value of 75.3% had a higher risk of developing oral cancer. The risk factors for tooth loss and periodontal disease showed moderate heterogenicity and less heterogenicity for oral hygiene. Poor oral health factors such as periodontal disease, poor oral hygiene, and loss of teeth show higher odds of oral cancer than the control. The periodontal disease shows the highest odds than other factors. These risk factors can be considered for the primordial prevention of oral cancer.

Chronic mechanical trauma/irritation and oral carcinoma: A systematic review showing low evidence to support an association

BACKGROUND

Chronic trauma of oral mucosa, resulting from repeated and persistent mechanical irritative action of an intraoral injury agent, has repeatedly been reported to be possibly implicated in the development of oral squamous cell carcinoma (OSCC).

OBJECTIVES

The present systematic review aimed to assess whether chronic mechanical trauma can be considered a risk factor for OSCC.

DATA SOURCES

PubMed, CENTRAL (Cochrane Central Register of Controlled Trials), Scopus; EMBASE, Web of Science.

STUDY ELIGIBILITY CRITERIA

Cohort studies comparing OSCC incidence among subjects with/without chronic mechanical trauma or case-control or cross-sectional studies comparing chronic mechanical trauma among subjects with/without OSCC.

RESULTS

Only one prospective case-control study fulfilled the inclusion criteria, but the quality of the evidence provided is not enough to define trauma as a risk factor for OSCC. The main limitation is the presence of only one case-control study at high risk of bias. In the absence of strong evidence supporting the role of trauma in OSCC, a thorough discussion on trauma and carcinogenesis has been performed.

CONCLUSIONS

Available evidence does not support an active role for chronic trauma in oral carcinogenesis, neither as promoter nor as progressor factor. Prospective cohort studies able to better assess trauma in OSCC are needed.

Chronic mechanical irritation enhances the effect of tobacco and alcohol on the risk of oral squamous cell carcinoma: a case-control study in Argentina

OBJECTIVES

Oral squamous cell carcinoma (OSCC) is a multifactorial disease. The individual effect of each risk factor for OSCC may be conditioned by the frequency of other factors. The objective of this study was to identify the association between chronic mechanical irritation (CMI) and OSCC and to analyse the influence of CMI on other important risk factors for OSCC.

MATERIALS AND METHODS

A prospective and age/sex-matched case-control study was performed in two institutions from Argentina between 2009 and 2019, with consecutive and newly diagnosed OSCC. The frequencies of tobacco, alcohol, and CMI were analysed using conditional logistic regression. Cumulative tobacco consumption and the presence of CMI were analysed using the Mann-Whitney test.

RESULTS

CMI and OSCC were associated with an OR of 7.02 (95% CI 3.57-13.78, p < 0.001). The combination of CMI and alcohol demonstrated the highest risk of OSCC (OR 53.83, CI 95% 8.04-360, p < 0.0001), followed by the combination of CMI, tobacco, and alcohol (OR 48.06, CI 95% 8.47-272, p < 0.0001). The combination of CMI and tobacco was also significant (OR 5.61, CI 95% 1.07-29.54, p = 0.042). Patients with CMI developed OSCC with less cumulative tobacco use compared with those without CMI.

CONCLUSION

CMI is an independent risk factor for OSCC, and it could act as a risk modifier among tobacco and alcohol users having an enhancing effect.

CLINICAL RELEVANCE

Elimination of CMI could decrease the risk of OSCC.

Dental health in patients with and without HPV-positive oropharyngeal and tongue cancer

Background

Human papilloma virus is associated with oral and oropharyngeal cancer. Our aim was to examine oral health in patients with oropharyngeal (OPSCC) and oral tongue cancer (OTSCC), expecting better oral health among OPSCC patients.

Material and methods

Fifty-five OPSCC patients with known HPV status and 59 OTSCC patients were randomly selected from a list of consecutive patients of the Helsinki University Hospital, Finland. Oral health was assessed from panoramic jaw radiographs. Total Dental Index (TDI) summarizing the dental health status was calculated and Finnish population study data were used for comparison. Descriptive statistics were used for analyses.

Results

Patients with HPV-positive OPSCC had higher periapical lesion index compared with HPV-negative OPSCC patients or with OTSCC patients. Residual roots were more common among OPSCC patients compared with OTSCC patients, because of their higher occurrence among HPV-negative OPSCC patients compared with OTSCC patients. Similarly, modified TDI score was significantly higher among OPSCC patients than among OTSCC patients, because of higher TDI score among HPV-negative OPSCC patients compared with OTSCC patients. OPSCC patients more often used a removable prosthesis than OTSCC patients. Dental health of the cancer patients was poorer when compared with the population data.

Conclusions

Our study hypothesis was only partly confirmed. Periapical lesions were more prevalent among HPV-positive OPSCC patients, compared with the other groups. The number of residual roots was higher among HPV-negative subgroup. Thus, OPSCC patients had worse oral health parameters than OTSCC patients.

High Failure Rates in Young Nonsmoker Nondrinkers With Squamous Cell Carcinoma of the Oral Tongue

OBJECTIVE(S)

There has been a disproportionate increase in the incidence of young patients with squamous cell carcinoma of the oral tongue (SCCOT). The purpose of this study was to compare young patients to older patients with SCCOT without prior drinking or smoking history as this population is poorly characterized in the literature.

METHODS

A retrospective review of patients presenting to our institution with SCCOT was performed. The clinical and pathologic characteristics, as well as, outcomes were compared between younger patients (age ≤45) and older patients (age >45). Outcome analysis was performed using Kaplan Meier method. Multivariable Cox proportional hazard models were performed for age and stage.

RESULTS

Eighty-two patients (38 young, 44 old) were included in this study. Median follow-up was 29.4 months. When compared to the older cohort (age >45), the younger cohort (age ≤45) demonstrated lower rates of 5-year locoregional control (LC) (79.6% vs. 52.5%, p = 0.043) and distant metastasis-free survival (88.1% vs. 61.8%, p = 0.006). Both cohorts demonstrated similar overall survival rates (55.5% vs. 58.1%) and disease-specific survival (66.2% vs. 58.1%). Of patients experiencing locoregional failure with available radiation therapy plans and PET scans in younger cohorts (n = 7), 100% demonstrated in-field failures. Multivariable Cox proportional hazards demonstrated age was an independent predictor of DMFS (p = 0.004) and the advanced stage was a predictor of DSS (p = 0.03).

CONCLUSIONS

Young, nondrinker, nonsmokers with SCCOT demonstrate high rates of locoregional recurrence, distant metastasis, and in-field failures. Future studies are warranted to determine underlying mechanisms driving pathogenesis in this unique cohort.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

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.

Effect of National Oral Health Screening Program on the Risk of Head and Neck Cancer: A Korean National Population-Based

Purpose

Poor oral health is associated with head and neck cancer (HNC). We evaluated whether a national oral health screening program (OHSP) could reduce the risk of HNC.

Materials and Methods

Data from 408,247 healthy individuals aged ≥ 40 years from the National Health Insurance System-National Health Screening program during 2003 and 2004 in Korea were analyzed. The risk of HNC was compared between subjects who underwent OHSP (HEALS-Dental+, n=165,292) and routine health check-ups only (HEALS-Dental‒, n=242,955). The impact of individual oral health-related factors on HNC risk was evaluated in HEALS-Dental+.

Results

A total of 1,650 HNC cases were diagnosed. The 10-year HNC-free rate was 99.684% with a median follow-up of 11 years. The risk of all HNC (hazard ratio [HR], 1.16; 95% confidence interval [CI], 1.03 to 1.29; p=0.011) and oropharyngeal cancer (HR, 1.48; 95% CI, 1.13 to 1.94; p=0.005) was significantly higher in HEALS-Dental‒ than in HEALS-Dental+. In HEALS-Dental+, oral cavity cancer was marginally reduced (p=0.085), and missing teeth was a significant factor for HNC (HR, 1.24; 95% CI, 1.02 to 1.50; p=0.032). Toothbrushing was a significant factor in univariate analysis (p=0.028), but not in multivariate analysis (p=0.877).

Conclusion

The National OHSP significantly reduced the long-term HNC risk, particularly the incidence of oropharyngeal cancer. Routine OHSP should be considered at the population level.

Diagnosis of an adenocarcinoma of Müllerian origin made as a result of its metastasis in the mouth floor

Metastases derived from primary tumours distant to the oral and maxillofacial region account for only 1% of all malignancies at that location, usually with a poor prognosis. In women, the primary tumours that most frequently metastasise to the oral cavity are breast adenocarcinomas affecting the jawbones and soft tissues (41% and 24%, respectively), followed by adrenal glands and female genital organs to the jawbones (8%), and female genital organs to the soft tissues (15%). Metastatic tumours of the mouth are a challenging diagnosis because of their exceptional occurrence. We report on the case of an 83-year-old woman who consulted for a bleeding ulcerated tumour on the floor of the mouth. A biopsy-confirmed metastasis of an adenocarcinoma of Müllerian origin. The oral lesion was the first sign of undetected cancer. The patient agreed to surgical resection and was further referred to palliative care for her symptoms.

Linking chronic periodontitis and oral cancer: A review

The aim of this article is to survey the accessible writing on the pathogenetic systems engaged with the relationship between oral malignancy and periodontitis. Gingival tissue contains multiple microbiota, which can induce inflammatory reactions. This reaction plays a crucial role in assessing the susceptibility of patients to periodontal diseases. The link between chronic periodontitis and the risk of malignancy through this inflammation of the affected epithelium have been studied thoroughly. Many studies have reported that, chronic periodontitis has systemic influence which has high risk of developing different types of cancers. Also, various confounding factors such as consumption of alcohol, smoking, diet, age and gender have been found to be associated with both chronic periodontitis and oral cancer. An online quest for a wide range of articles distributed was started utilizing MEDLINE/PubMed, with the keywords, for example, 'oral squamous cell carcinoma (OSCC)', 'oral microbiota,' 'microorganisms and malignancy and Porphyromonas gingivalis. This review aimed to study the current literature linking chronic periodontitis and oral cancer.

Smoking and Drinking Adjusted Association between Head and Neck Cancers and Oral Health Status Related to Periodontitis: a Meta-Analysis

BACKGROUND

Not so many reports about the association between head and neck cancer (HNC) and oral health status related to periodontitis (OHS-P) has been published in different countries with different methods. So, there is a need for an extensive meta-analysis with the total articles published until 2020. Hence, this study aimed to estimate the association between HNC and OHS-P through a meta-analysis.

METHODS

Based on Preferred Reporting Items for Systematic Reviews and Meta Analyses guidelines, 22 studies were selected through PubMed and Cochrane Library databases. Meta-analysis using them was performed to evaluate the association. The risk of bias assessment using the Newcastle-Ottawa Scale (NOS) was applied to evaluate the quality of non-randomized studies. Publication bias was evaluated by funnel plot and Egger's regression test.

RESULTS

Since heterogeneity was significant (I² = 88%, P < 0.001), we adopted the random effect model for 22 studies. Those with bad OHS-P, compared to those with good OHS-P, were more likely to have the risk of HNC by 2.4 times (odds ratio [OR], 2.42; 95% confidence interval [CI], 1.88-3.13) for random effect model. The association included publication bias (Egger's regression, P value < 0.001). The association among five studies (I² = 39%, P = 0.16) using alveolar bone loss (ABL) or clinical attachment level (CAL) for assessing periodontitis increased to OR of 3.85 (CI, 3.04-4.88) in the fixed effect model without publication bias (Egger's regression, P = 0.66). Moreover, the association was higher in 10 fair or good NOS studies (OR, 3.08) and in 7 Asian studies (OR, 2.68), which were from the fixed model without publication bias.

CONCLUSION

Our meta-analysis showed that bad OHS-P was associated with the risk of HNC. The association was stronger in studies using ABL or CAL for assessing periodontitis.

A systematic review and meta-analysis of the prognostic role of age in oral tongue cancer

While evidence suggests an increasing incidence of tongue cancer in young adults, published findings regarding the prognostic role of age at diagnosis are inconsistent. We performed a meta-analysis of the literature to highlight key points that might help in understanding the association between age of oral tongue cancer patients at diagnosis and their prognosis. According to age at diagnosis, a systematic literature review of all published cohort studies assessing the recurrence risks and mortality associated with tongue cancer was conducted. We compared the risk estimates between patients aged >45 years and those aged <45 years at diagnosis. Random-effects models were used to calculate summary relative risk estimates (SRRs) according to different clinical outcomes and sources of between-study heterogeneity (I2 ) and bias. We included 31 independent cohort studies published between 1989 and 2019; these studies included a total of 28,288 patients. When risk estimations were not adjusted for confounders, no significant association was found between age at diagnosis and overall survival (OS). Conversely, after adjustment for confounders, older age at diagnosis was associated with a significantly increased risk of mortality. The difference between SRRs for adjusted and unadjusted estimates was significant (p < 0.01). Younger patients had a significantly higher risk of local recurrence. Younger patients with oral tongue cancer have better OS but a greater risk of recurrence than older patients. These findings should be validated in a large prospective cohort study which considers all confounders and prognostic factors.

Head and neck cancer and non-steroidal anti-inflammatory drugs: Systematic review and meta-analysis

The objective was to assess the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on head and neck cancer (HNC) outcomes. A systematic review was conducted following the PRISMA guidelines. The MEDLINE and the Cochrane Central Register databases were searched. Risk of bias was assessed by the Cochrane Collaboration's tool and by the Newcastle-Ottawa Scale. Meta-analyses were performed with the RevMan software. Seventeen articles met the inclusion criteria. Quality scores for observational studies ranged between 5 and 8 stars and the RCT was assessed as high risk of bias. NSAIDs use was associated with a 13% risk reduction of HNC (OR: 0.87 95% CI 0.77-0.99). NSAIDs use was associated with a 30% reduced cancer-specific mortality and with a 40% decreased risk on disease-recurrence. NSAIDs may have a modest protective effect on HNC risk and a positive impact on cancer-specific survival and disease-recurrence. The findings do not support a protective role of aspirin on HNC outcomes.

New Insights Into Oral Squamous Cell Carcinoma: From Clinical Aspects to Molecular Tumorigenesis

Oral squamous cell carcinoma (SCC) is a prevalent malignant disease worldwide, especially so in Taiwan. Early- or even preclinical-stage detection is critical for reducing morbidity and mortality from oral SCC. Epidemiological and genome association studies are useful for identifying clinicopathological risk factors for preventive, diagnostic, and therapeutic approaches of oral SCC. For advanced oral SCC, effective treatments are critical to prolonging survival and enhancing quality of life. As oral SCC is characteristic of regional invasion with lymph node metastases, understanding the aggressive features of oral SCC, particularly in lymphangiogenesis, is essential for determining effective treatments. Emerging evidence has demonstrated that the tumor microenvironment (TME) plays a pivotal role in tumor growth, invasion, and metastases. Recent clinical successes in immune checkpoint inhibitors either alone or combined with chemotherapy have also supported the therapeutic value of immunotherapy in oral SCC. This review summarizes critical advances in basic knowledge of oral SCC from the perspective of clinicopathological risk factors, molecular tumorigenesis, and the TME. We also highlight our recent investigations on the microbiome, genome association studies, lymphangiogenesis, and immunomodulation in oral SCC. This review may provide new insights for oral SCC treatment by systematically interpreting emerging evidence from various preclinical and clinical studies.

Epidemiologic factors in patients with advanced head and neck cancer treated with radiation therapy

BACKGROUND

Approximately 50% of patients with head and neck cancer (HNC) initially were seen with advanced disease. We aimed to evaluate the association of epidemiologic factors with advanced HNC at diagnosis.

METHODS

The OraRad multicenter prospective cohort study enrolled HNC patients receiving curative-intent radiation therapy. Factors assessed for association with advanced HNC presentation at diagnosis included demographics, social and medical history, cancer characteristics, human papilloma virus (HPV) status, and dental disease measures.

RESULTS

We enrolled 572 participants; 77% male and mean (SD) age of 61.7 (11.2) years. Oropharyngeal squamous cell carcinomas (88% HPV-related) were seen with smaller tumors, but more frequent nodal involvement. Private medical insurance and no Medicaid were associated with smaller tumors. A higher dental disease burden was associated with larger tumors.

CONCLUSIONS

Insurance status, cancer type/location, and dental disease are associated with advanced HNC and may represent potentially modifiable factors or factors to be considered in the screening process of new lesions.

Possible association of periodontal disease with oral cancer and oral potentially malignant disorders: a systematic review

Background: Periodontitis has been associated with several systemic diseases and medical conditions, including oral cancer (OC). However, most studies reporting an association between OC and periodontal disease have used different clinical and radiographic criteria to define periodontal disease. This review aimed to evaluate the currently available evidence to determine an association between periodontal disease (extension and severity), OC, and oral potentially malignant disorders (OPMDs).Material and methods: A systematic search of studies published up to August 2018 was performed following the PRISMA guidelines in the electronic databases MEDLINE (PubMed) and COCHRANE (OVID). A methodological evaluation was made using the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) checklist.Results: Eight studies (case-control, cross-sectional and cohort) were included. An increased clinical attachment loss, plaque index, bleeding on probing, and radiographic bone loss was found in patients with OC and OPMDs. Differences in the methodological characteristics, case definition used for periodontal diseases, and OC location did not allow estimating the odds ratio required to conduct a meta-analysis.Conclusion: Some studies suggest a positive relationship between periodontal disease, OC, and OPMDs; however, the currently available evidence is insufficient to draw solid conclusions.

World Small Animal Veterinary Association Global Dental Guidelines

Dental, oral, and maxillofacial diseases are some of the most common problems in small animal veterinary practice. These conditions create significant pain as well as localized and potentially systemic infection. As such, the World Small Animal Veterinary Association (WSAVA) believes that un- and under treated oral and dental diseases pose a significant animal welfare concern. Dentistry is an area of veterinary medicine which is still widely ignored and is subject to many myths and misconceptions. Effective teaching of veterinary dentistry in the veterinary school is the key to progression in this field of veterinary medicine, and to the improvement of welfare for all our patients globally. These guidelines were developed to provide veterinarians with the information required to understand best practices for dental therapy and create realistic minimum standards of care. Using the three-tiered continuing education system of WSAVA, the guidelines make global equipment and therapeutic recommendations and highlight the anaesthetic and welfare requirements for small animal patients. This document contains information on common oral and dental pathologies, diagnostic procedures (an easily implementable and repeatable scoring system for dental health, dental radiography and radiology) and treatments (periodontal therapy, extractions). Further, there are sections on anaesthesia and pain management for dental procedures, home dental care, nutritional information, and recommendations on the role of the universities in improving veterinary dentistry. A discussion of the deleterious effects of anaesthesia free dentistry (AFD) is included, as this procedure is ineffective at best and damaging at worst. Throughout the document the negative effects of undiagnosed and/or treated dental disease on the health and well-being of our patients, and how this equates to an animal welfare issue, is discussed.

Association of viral load and physical status of HPV-16 with survival of patients with head and neck cancer

Introduction

Head and neck cancers (NHCs) are of multifaceted origins, and tobacco and alcohol are the primary risk factors. Currently, other factors associated with the genesis of these tumours are being considered, among these viral infections, especially human papillomavirus (HPV) infection.

Objective

The objective was to evaluate HPV infection, HPV-16 E6 load and its physical status in patients with squamous cell carcinoma in the head and neck and evaluate its effects in the survival of these patients.

Methodology

A total of 80 fresh biopsies of HNC were evaluated. The genetic material was extracted using the commercial kit QIAGEN. The detection and classification of HPV were carried out using INNO-LiPA, whereas the quantification and analysis of integration of the viral genome into the host cell were carried out using real-time PCR.

Results

The average age of the patients included was 60.34 ± 14.48 years, with a predominance of the male gender. The most frequent HPV infection was genotype 16 (52.8%), with an average of 10 copies of the HPV-16 E6/β-globin gene. Furthermore, an integration of the viral genome in the host cell was observed in 86% of cases with a statistically significant relationship between the location of the tumour and the viral load (p < 0.05).

Conclusions

HPV-16 is the most common infection, and its physical status in the host cell is the determining factor in establishing response to treatment. However, more studies are needed to demonstrate the role of HPV infection in carcinogenesis.

Alveolar Bone Loss, Tooth Loss and Oral Cancer Mortality in Older Patients: A Retrospective Cohort Study

PURPOSE

There has been growing interest in the association between periodontitis and systemic disease. In recent years, however, inconsistent results have also been found by case-control studies for the role of periodontitis in the development of oral cancer. This study aimed to examine whether periodontitis was an independent risk factor for oral cancer with a ≥75-year age group cohort.

MATERIALS AND METHODS

Between January 2010 and December 2014, 1385 patients aged ≥75 years who underwent radiographic examination were included in this retrospective cohort study. We collected demographic information and comorbid health conditions from local health authorities. Participants were followed up until either the occurrence of mortality, or the end of the study on December 31, 2018. Cox proportional hazards regression and competing risk hazard models were used to examine the association between periodontitis and oral cancer mortality.

RESULTS

Periodontitis and loss of teeth were significantly associated with oral cancer mortality. Compared to oral cancer mortality in healthy subjects, the HR and 95% CI in patients with mild, moderate, and severe periodontitis were 4.46 (0.94-21.06), 5.16 (1.14-23.39), and 6.65 (1.51-29.36), respectively. The HR (95% CI) was 1.05 (1.01-1.09) for tooth loss after controlling for potential confounding factors. All the increases in risk persisted in patients aged ≥80 years.

CONCLUSION

The present study provides substantial evidence that poor periodontal health is associated with oral cancer mortality. It is necessary to underline the importance of considering periodontitis in the prevention of oral cancer, particularly in the older patients.

Periodontal disease and cancer: Epidemiologic studies and possible mechanisms

Epidemiologic and cancer control studies on the association of periodontal disease and cancer risk mostly suggest a positive association with overall cancer risk and certain specific types of cancer. These findings are generally consistent among cross‐sectional and longitudinal studies. In this paper, we review epidemiologic studies and current knowledge on periodontal disease and cancer, with a focus on those studies conducted in the years following the Joint European Federation of Periodontology/American Academy of Periodontology Workshop on “Periodontitis and Systemic Diseases” in November 2012. This review also explores the role of chronic inflammation as a biologically plausible mechanistic link between periodontal disease and risk of cancer. Furthermore, it highlights studies that have examined the potential importance of certain periodontal pathogens in this association.

Periodontal Diseases as Putative Risk Factors for Head and Neck Cancer: Systematic Review and Meta-Analysis

Whether "periodontal disease" can be considered as an independent risk factor for head and neck cancer (HNC) remains controversial. The aim of the current meta-analysis was to quantitatively assess this relationship in order to determine whether this represents a true risk factor, with implications for cancer prevention and management. PubMed, Scopus, and Embase databases were systematically searched. Selective studies were reviewed, and meta-analysis was performed to estimate the pooled odds ratio (OR) with 95% confidence intervals (CIs) on eligible studies using a random effects model. In total, 21 eligible observational studies (4 cohorts and 17 case-controls) were identified for qualitative synthesis after a review of 1051 articles. Significant heterogeneity could be identified in measures utilized for reporting of periodontal disease. Meta-analysis performed on nine studies that employed objective measures for reporting periodontal disease demonstrated a significant association between periodontal disease and HNC [OR 3.17, 95% CI, 1.78-5.64]. A diseased periodontium represents an independent risk marker, and a putative risk factor, for HNC. Prospective studies with standardized measures of periodontal disease severity and extent, integrated with microbiological and host susceptibility facets, are needed to elucidate the mechanisms of this positive association and whether treatment of the former influences the incidence and outcomes for HNC.

Difference between Female and Male Patients with Oral Squamous Cell Carcinoma: A Single-Center Retrospective Study in Taiwan

There is a distinct male predominance in head and neck cancers. The present study aimed to investigate the clinical and pathological features of male and female patients with oral squamous cell carcinoma (OSCC), and to simultaneously conduct a survival analysis. Patients (n = 2573) were identified between January 2008 and December 2018, and subsequently analyzed for characteristics such as age at squamous cell carcinoma diagnosis, lifestyle factors (smoking habit, betel nut chewing and alcohol consumption), pathological American Joint Committee on Cancer (AJCC) anatomic site, AJCC TNM stage, pathological recurrence factor and interval from first diagnosis to recurrence. A case-matched comparison between female (n = 122) and male (n = 2451) patients was conducted. Significant gender differences were noted in age at diagnosis, anatomic site of the tumor, smoking habit, betel nut chewing and alcohol consumption (p < 0.001). There were no significant gender differences in the other clinical and pathological characteristics and survival conditions. In conclusion, female patients with OSCC were older than male patients with OSCC, and mostly had tumors of the oral tongue. Once patients develop OSCC, there was no difference in survival between men and women in a Taiwanese population.

Association of oral dysbiosis with oral cancer development

Oral squamous cell carcinoma (OSCC) is the leading cause of mortality for oral cancer. Numerous risk factors mainly related to unhealthy habits and responsible for chronic inflammation and infections have been recognized as predisposing factors for oral carcinogenesis. Recently, even microbiota alterations have been associated with the development of human cancers. In particular, some specific bacterial strains have been recognized and strongly associated with oral cancer development (Capnocytophaga gingivalis, Fusobacterium spp., Streptococcus spp., Peptostreptococcus spp., Porphyromonas gingivalis and Prevotella spp.). Several hypotheses have been proposed to explain how the oral microbiota could be involved in cancer pathogenesis by mainly paying attention to chronic inflammation, microbial synthesis of cancerogenic substances, and alteration of epithelial barrier integrity. Based on knowledge of the carcinogenic effects of dysbiosis, it was recently suggested that probiotics may have anti-tumoral activity. Nevertheless, few data exist with regard to probiotic effects on oral cancer. On this basis, the association between the development of oral cancer and oral dysbiosis is discussed focusing attention on the potential benefits of probiotics administration in cancer prevention.

Association of subcutaneous and visceral adipose tissue with overall survival in Taiwanese patients with bone metastases - results from a retrospective analysis of consecutively collected data

BACKGROUND

Growing evidence indicates that measures of body composition may be related to clinical outcomes in patients with malignancies. The aim of this study was to investigate whether measures of regional adiposity-including subcutaneous adipose tissue index (SATI) and visceral adipose tissue index (VATI)-can be associated with overall survival (OS) in Taiwanese patients with bone metastases.

METHODS

This is a retrospective analysis of prospectively collected data. We examined 1280 patients with bone metastases who had undergone radiotherapy (RT) between March 2005 and August 2013. Body composition (SATI, VATI, and muscle index) was assessed by computed tomography at the third lumbar vertebra and normalized for patient height. Patients were divided into low- and high-adiposity groups (for both SATI and VATI) according to sex-specific median values.

RESULTS

Both SATI (hazard ratio [HR]: 0.696; P<0.001) and VATI (HR: 0.87; P = 0.037)-but not muscle index-were independently associated with a more favorable OS, with the former showing a stronger relationship. The most favorable OS was observed in women with high SATI (11.21 months; 95% confidence interval: 9.434-12.988; P<0.001).

CONCLUSIONS

High SATI and VATI are associated with a more favorable OS in Taiwanese patients with bone metastases referred for RT. The question as to whether clinical measures aimed at improving adiposity may improve OS in this clinical population deserves further scrutiny.

Characteristics and prognosis of primary treatment-naïve oral cavity squamous cell carcinoma in Norway, a descriptive retrospective study

Objectives

Incidence of oral cavity squamous cell carcinomas is rising worldwide, and population characterization is important to follow for future trends. The aim of this retrospective study was to present a large cohort of primary oral cavity squamous cell carcinoma from all four health regions of Norway, with descriptive clinicopathological characteristics and five-year survival outcomes.

Materials and methods

Patients diagnosed with primary treatment-naïve oral cavity squamous cell carcinomas at all four university hospitals in Norway between 2005–2009 were retrospectively included in this study. Clinicopathological data from the electronic health records were compared to survival data.

Results

A total of 535 patients with primary treatment-naïve oral cavity squamous cell carcinomas were identified. The median survival follow-up time was 48 months (range 0–125 months) after treatment. The median five-year overall survival was found to be 47%. Median five-year disease-specific survival was 52%, ranging from 80% for stage I to 33% for stage IV patients. For patients given treatment with curative intent, the overall survival was found to be 56% and disease-specific survival 62%. Median age at diagnosis was 67 years (range 24–101 years), 64 years for men and 72 years for women. The male: female ratio was 1.2. No gender difference was found in neither tumor status (p = 0.180) nor node status (p = 0.266), but both factors influenced significantly on survival (p<0.001 for both).

Conclusions

We present a large cohort of primary treatment-naïve oral cavity squamous cell carcinomas in Norway. Five-year disease-specific survival was 52%, and patients eligible for curative treatment had a five-year disease-specific survival up to 62%.

Mouth Cancer Awareness in General Population: Results from Grampian Region of Scotland, United Kingdom

Objectives

The purpose of this project was to determine the level of mouth cancer awareness and to investigate the associated factors in a United Kingdom (UK) general population sample.

Material and Methods

Adult Dental Health Survey (2010) was conducted in a sample of 3,353 adult residents in the Grampian region of the UK (adjusted participation rate 58%). Participants completed a questionnaire consisting of questions on oral health, health behaviour, quality of life and cancer awareness.

Results

Overall, 81% of participants were aware of mouth cancer. This was associated with younger age, higher levels of education and better general health. Current smokers and alcohol drinkers were more aware of mouth cancer. When asked about risk factors for mouth cancer, the following were identified by the respondents: smoking (84%), poor oral hygiene (60%), drinking alcohol heavily (59%), poor diet (37%), stress (15%), being overweight (6%), drinking hot liquids (5%), eating spicy food (3%), using mouthwash (2%) and kissing someone (1%). Smokers were more likely to identify smoking as a risk factor for mouth cancer. Similarly, those who consumed alcohol almost daily were more likely to identify heavy alcohol drinking as a risk factor.

Conclusions

Awareness of mouth cancer is high in respondents from the general population, and participants were able to identify the most important risk factors. Knowledge of tobacco and alcohol as risk factors was highest amongst those exposed to them. The study proposed that the prevention strategies should focus not only on increasing knowledge, but also on changing health behaviour.

Effect of tobacco on periodontal disease and oral cancer

INTRODUCTION

Periodontal disease and oral cancer are common health hazards. Epidemiological investigations show that smoking, periodontal disease and oral cancer are closely related. Tobacco is one of the major risk factors for periodontitis and oral cancer.

METHODS

A systematic literature review was performed. To identify relevant studies, the following online databases were searched using specific keywords: PubMed, Web of Science and CNKI.

RESULTS

Tobacco not only possesses an addictive effect, but it aggravates periodontal disease by promoting the invasion of pathogenic bacteria, inhibiting autoimmune defense, aggravating the inflammatory reaction, and aggravating the loss of alveolar bone. According to current evidence, tobacco significantly aggravates the development and progression of periodontal disease and oral cancer, and periodontal disease may be related to the prevalence of oral cancer.

CONCLUSIONS

Clinicians should strongly recommend that smokers undertake a strategy to stop smoking to avoid the exacerbation of nicotine-related periodontal disease and to reduce the incidence of oral cancer.

Chronic Inflammation as a Link between Periodontitis and Carcinogenesis

Periodontitis is characterized by a chronic inflammation produced in response to a disease-associated multispecies bacterial community in the subgingival region. Although the inflammatory processes occur locally in the oral cavity, several studies have determined that inflammatory mediators produced during periodontitis, as well as subgingival species and bacterial components, can disseminate from the oral cavity, contributing therefore, to various extraoral diseases like cancer. Interestingly, carcinogenesis associated with periodontal species has been observed in both the oral cavity and in extra oral sites. In this review, several studies were summarized showing a strong association between orodigestive cancers and poor oral health, presence of periodontitis-associated bacteria, tooth loss, and clinical signs of periodontitis. Proinflammatory pathways were also summarized. Such pathways are activated either by mono- or polymicrobial infections, resulting in an increase in the expression of proinflammatory molecules such as IL-6, IL-8, IL-1β, and TNF-α. In addition, it has been shown that several periodontitis-associated species induce the expression of genes related to cell proliferation, cell cycle, apoptosis, transport, and immune and inflammatory responses. Intriguingly, many of these pathways are linked to carcinogenesis. Among them, the activation of Toll-like receptors (TLRs) and antiapoptotic pathways (such as the PI3K/Akt, JAK/STAT, and MAPK pathways), the reduction of proapoptotic protein expression, the increase in cell migration and invasion, and the enhancement in metastasis are addressed. Considering that periodontitis is a polymicrobial disease, it is likely that mixed species promote carcinogenesis both in the oral cavity and in extra oral tissues and probably—as observed in periodontitis—synergistic and/or antagonistic interactions occur between microbes in the community. To date, a good amount of studies has allowed us to understand how monospecies infections activate pathways involved in tumorigenesis; however, more studies are needed to determine the combined effect of oral species in carcinogenesis.

Oral hygiene and the overall survival of head and neck cancer patients

Poor oral hygiene is an established risk factor of head and neck cancer (HNC); however, its role in the survival of HNC patients is unclear. This study evaluated the association between oral hygiene habits, including regular dental visits, frequency of tooth brushing, and use of dental floss, and the overall survival (OS) of HNC patients using interview data collected from 740 HNC patients. In addition, the interactions between oral hygiene and the polymorphisms of TLR2 and TLR4 on the OS of HNC patients were assessed. The analysis indicated that poor oral hygiene was significantly associated with poorer OS of HNC patients (hazard ratio (HR) = 1.38, 95% confidence interval (CI): 1.03‐1.86). This association was modified by a single nucleotide polymorphism, rs11536889, of TLR4. A significant association between poor oral hygiene and worse survival of HNC was observed among those with the CG or CC genotype (HR = 2.32, 95% CI: 1.41‐3.82) but not among those with the GG genotype (HR = 0.95, 95% CI: 0.65‐1.40). Our results suggested that poor oral hygiene is not only a risk factor but may also be a prognostic factor of HNC.

Poor oral hygiene was associated with a worse survival of head and neck cancer. TLR4 affected the survival of head and neck cancer due to poor oral hygiene. Poor oral hygiene is both a risk and a prognostic factor of head and neck cancer

Association of Periodontitis with Oral Cancer: A Case-Control Study

The association between oral squamous cell carcinoma (OSCC) and periodontitis in large hospital cases with cohort controls has yet to be evaluated. The aim of this study was to investigate the association of periodontitis with OSCC across tumor location and tumor-node-metastasis (TNM) stage among Koreans ( N = 424). OSCC cases ( n = 146) were recruited from Seoul National University Dental Hospital and matched by age, sex, and smoking to controls ( n = 278) from the Yangpyeong health and periodontal cohort in Korea. OSCC was diagnosed through biopsy and radiographs, including computed tomography and magnetic resonance imaging. Tumor location and TNM stage were classified after the surgery. Periodontitis was defined by alveolar bone loss with panoramic radiographs following the guidelines of the Fifth European Workshop in Periodontology. Alcohol intake, education, physical activity, obesity by body mass index, hypertension by blood pressure, diabetes by plasma glucose, and hypercholesterolemia by plasma cholesterol were considered as confounders. Information about age, sex, smoking, alcohol intake, education, and physical activity was obtained through interview; body mass index and blood pressure, through physical examination; and preoperative glucose and cholesterol, through laboratory tests. Bivariate analysis was applied with Fisher’s exact chi-square test. Multivariable conditional logistic regression models were applied to evaluate the adjusted association of periodontitis with OSCC after controlling for confounders. Subgroup analyses were explored by OSCC and periodontitis. Participants with periodontitis were 3.7 times more likely to have OSCC (adjusted odds ratio [aOR] = 3.66, 95% CI = 1.46 to 9.23) than participants without periodontitis. The differences in periodontitis were not statistically significant across TNM stages of OSCC ( P > 0.05) and its location ( P > 0.05). The link was highlighted among males (aOR = 6.55), elders aged >60 y (aOR = 4.98), and those with more tooth loss (aOR = 9.99). Our data showed that periodontitis was independently associated with OSCC. Thus, the risk of OSCC could be modulated by reducing periodontitis.

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.

The interplay between oral microbiome, lifestyle factors and genetic polymorphisms in the risk of oral squamous cell carcinoma

Poor oral hygiene may lead to overgrowth of pathogenic oral bacteria, which may induce chronic inflammation to promote the oncogenesis of oral squamous cell carcinoma (OSCC). This study investigated the association between oral bacterial profile and OSCC risk in a case-control study of 138 OSCC cases and 151 controls (88 cases and 90 controls for the discovery group and 50 cases and 61 controls for the validation group). Oral bacterial profiles were characterized by targeted sequencing of the 16S rRNA gene. Three species of periodontopathogenic bacteria, Prevotella tannerae, Fusobacterium nucleatum, and Prevotella intermedia, were associated with an increased OSCC risk. This association was modified by the genetic polymorphisms of TLR2 and TLR4. Use of alcohol, betel quids and cigarettes and poor oral hygiene were associated with a higher percentage of oral periodontopathogenic bacteria. The association between alcohol and periodontopathogenic bacteria was modified by the genetic polymorphism of ALDH2, with a stronger positive association observed among the ALDH2-deficient individuals. The percentage of periodontopathogenic bacteria was positively correlated with the level of salivary IL1β, an inflammatory cytokine. Overall, our results showed a positive association between periodontopathogenic bacteria and OSCC risk and this relationship may be influenced by lifestyle and genetic factors. Our results provided further biological support for the established association between poor oral hygiene and OSCC risk. This suggested that improving oral hygiene may reduce OSCC risk and should be part of a public health campaign to prevent the occurrence of OSCC.

Associations Between Poor Oral Health and Risk of Squamous Cell Carcinoma of the Head and Neck: A Meta-Analysis of Observational Studies

PURPOSE

Many epidemiologic studies have reported an association of poor oral health, especially periodontal disease (PD) and tooth loss, with the risk of squamous cell carcinoma of the head and neck (SCCHN). However, these studies have yielded inconsistent results. Therefore, the present study investigated whether poor oral health is an independent predictor of SCCHN through a meta-analysis of observational studies.

MATERIALS AND METHODS

The PubMed, EMBASE, and Cochrane Library databases were systematically searched for relevant observational studies of the association between oral health and risk of SCCHN conducted up to October 2017. The meta-analysis was conducted using STATA 12.0 (StataCorp, College Station, TX). A fixed- or random-effects model was applied to evaluate pooled risk estimates, and sensitivity and subgroup analyses were performed to identify sources of heterogeneity and pooled estimation. Publication bias was assessed using the Begg test, the Egger test, and funnel plots.

RESULTS

Twenty-seven relevant observational studies were identified, consisting of 24 case-and-control studies, 2 prospective studies, and 1 cross-sectional study, with 26,750 participants. Notably, oral health correlated meaningfully with SCCHN (odds ratio [OR] = 2.24; 95% confidence interval [CI], 1.77-2.82). In subgroup analyses, participants with PD (OR = 2.52; 95% CI, 1.43-4.44) had a higher risk of developing SCCHN than those with tooth loss (OR = 2.13; 95% CI, 1.63-2.78). The risk estimates exhibited substantial heterogeneity. Evidence of publication bias was limited.

CONCLUSIONS

The results of this meta-analysis suggest that patients with tooth loss or PD might face a substantial and independent risk of SCCHN, even after adjusting for smoking and alcohol consumption. However, the pooled estimates from observational studies could not establish a causative relation among PD, tooth loss, and SCCHN. Additional investigations of this correlation are warranted.

Medical History, Medication Use, and Risk of Nasopharyngeal Carcinoma

Because persistent inflammation may render the nasopharyngeal mucosa susceptible to carcinogenesis, chronic ear-nose-throat (ENT) disease and its treatment might influence the risk of nasopharyngeal carcinoma (NPC). Existing evidence is, however, inconclusive and often based on methodologically suboptimal epidemiologic studies. In a population-based case-control study in southern China, we enrolled 2,532 persons with NPC and 2,597 controls, aged 20-74 years, from 2010 to 2014. Odds ratios were estimated for associations between NPC risk and history of ENT and related medications. Any history of chronic ENT disease was associated with a 34% increased risk of NPC. Similarly, use of nasal drops or aspirin was associated with approximately doubled risk of NPC. However, in secondary analyses restricted to chronic ENT diseases and related medication use at least 5 years prior to diagnosis/interview, most results were statistically nonsignificant, except a history of uncured ENT diseases, untreated nasal polyps, and earlier age at first diagnosis of ENT disease and first or most recent aspirin use. Overall, these findings suggest that ENT disease and related medication use are most likely early indications rather than causes of NPC, although the possibility of a modestly increased NPC risk associated with these diseases and related medications cannot be excluded.

Aspirin associated with risk reduction of secondary primary cancer for patients with head and neck cancer: A population-based analysis

As reported by the Taiwan Cancer Registry in 2013 squamous cell carcinoma of head and neck cancer (HNSCC) was the sixth most frequently diagnosed cancer and the 5th most common cause of cancer related death and its incidence and mortality rate is still rising. The co-occurrence of HNSCC and secondary primary cancer (SPC) and the chemopreventive effect of aspirin on certain malignancies had been reported. Therefore we conducted this national study to investigate the use of aspirin associated with risk reduction of secondary primary cancer for patients with head and neck cancer in Taiwan. We searched the Registry for Catastrophic Illness in the National Health Insurance Research Database (NHIRD) for 18,234 patients (3,576 aspirin users and 14,667 non-aspirin users) diagnosed with HNSCC during 2000-2005. The SPC incidence density during follow-up in 2000-2011 was compared between the groups. For HNSCC patients, aspirin use after diagnosis was significantly associated with SPC risk reduction by 25% (adjusted HR, 0.75; 95% CI, 0.63-0.89; p = 0.001) after multivariate analysis. In the subgroup analysis, we found that esophageal cancer and stomach cancer incidence were significantly reduced after aspirin use (adjusted HR, 0.60; 95% CI, 0.41-0.90; p = 0.01 for esophageal cancer; adjusted HR, 0.27; 95% CI, 0.08-0.87; p = 0.03 for stomach cancer). Aspirin use for 1-3 years was associated with SPC risk reduction by 35% (adjusted HR, 0.65; 95% CI, 0.49-0.87; p = 0.003). SPC risk reduction extended continuously for more than 3 years of follow up (adjusted HR, 0.72; 95% CI, 0.53-0.98; p = 0.030). Our data shows aspirin use was associated with reduced SPC incidence for HNSCC patients, attributed mainly to reduced risk of esophageal and stomach cancer.

Association between poor oral health and gastric cancer: A prospective cohort study

Poor oral health may be involved in the pathogenesis of gastric cancer, however, some aspects have not been explored. Further, for previously studied aspects, for example, tooth-loss, the findings are inconsistent. We conducted a prospective cohort study of 19,831 participants from Uppsala, Sweden, cancer-free at baseline in 1973-1974 and followed until 2012 through linkage to national registers. We found that individuals with fewest teeth at baseline had an increased risk of gastric cancer relative to subjects with all examined teeth present (p = 1.75e-2). Presence of denture-associated lesions was also associated with an increased risk of gastric cancer (p = 1.00e-4). However, these excess risks significantly varied with attained age; estimated hazard ratio (HR) at attained age 50 for tooth loss was 4.24 [95% confidence interval (CI) 1.83-9.80] and 5.91 (95% CI 2.76-12.63) for denture-associated lesions, decreasing at an estimated 4% and 6% per year respectively, resulting in HR of 1.54 (95% CI 0.90-2.64) for tooth loss and HR 1.29 (95% CI 0.90-1.85) for denture-associated lesions at attained age 75. No increased risk of gastric cancer was found for individuals with higher levels of dental plaque, or with Candida-related or tongue lesions. In conclusion, tooth-loss and denture-associated lesions are associated with increased risks of gastric cancer. Previous conflicting findings of tooth-loss and gastric cancer risk may partly be explained by the age-varying relative risk of gastric cancer.

Epidemiology and Demographics of the Head and Neck Cancer Population

Head and neck malignancies comprise a heterogeneous group of malignancies that cause significant morbidity to those affected. These malignancies are associated with specific risk factors and exposures, some of which impact prognosis. The most common risk factors for developing head and neck cancers are tobacco and alcohol use. Marijuana and e-cigarettes, occupational exposures, and use of topical substances have also been linked to head and neck cancers. Human papilloma virus has been associated with oropharyngeal cancer. Such measures as oral hygiene, screening, smoking cessation, and vaccination are measures taken to decrease the incidence and morbidity of head and neck cancers.

Is periodontitis a risk indicator for cancer? A meta-analysis

Background

The aim of the present systematic review was to evaluate the hypothesis of an association between periodontitis and the development of cancer.

Methods

Two reviewers independently screened electronic and manual sources for pertinent articles. Primary outcome measures were the occurrence of neoplasm diagnosis in exposed and non-exposed groups, reported to evaluate association between cancer and periodontitis.

Results

Of the 490 initially retrieved papers 10 were included in the qualitative synthesis and eight in the quantitative synthesis; the eight papers covered six studies. Considering hazard ratios, a statistically significant association was found for all cancers studied (1.14; CI 95%: 1.04, 1.24), digestive tract cancer (1.34; CI 95%: 1.05, 1.72), pancreatic cancer (1.74; CI 95%: 1.21, 2.52), prostate cancer (1.25; CI 95%: 1.04, 1.51), breast cancer (1.11; CI 95%: 1.00, 1.23), corpus uteri cancer (2.20; CI 95%: 1.16, 4.18), lung cancer (1.24; CI 95%: 1.06, 1.45), hematological cancer (1.30; CI 95%: 1.11, 1.53), esophagus / oropharyngeal cancer pooled together (2.25; CI 95%: 1.30, 3.90) and Non-Hodgkin lymphoma (1.30; CI 95%: 1.11, 1.52).

Conclusions

Despite the sparse scientific evidence and considering the low statistical power of the results, this systematic review revealed a substantial lack of studies with standardized and comparable methods to speculate about the association between periodontitis and cancer; more studies are need in order to explore further the scientific evidence of such correlation.