Periodontal disease and mouthwash use are risk factors for head and neck squamous cell carcinoma

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.

The effect of daily usage of Listerine Cool Mint mouthwash on the oropharyngeal microbiome: a substudy of the PReGo trial

Introduction. ListerineÒ is a bactericidal mouthwash widely used to prevent oral health problems such as dental plaque and gingivitis. However, whether it promotes or undermines a healthy oral microbiome is unclear.Hypothesis/Gap Statement. We hypothesized that the daily use of Listerine Cool Mint would have a significant impact on the oropharyngeal microbiome.Aim. We aimed to assess if daily usage of Listerine Cool Mint influenced the composition of the pharyngeal microbiome.Methodology. The current microbiome substudy is part of the Preventing Resistance in Gonorrhoea trial. This was a double-blind single-centre, crossover, randomized controlled trial of antibacterial versus placebo mouthwash to reduce the incidence of gonorrhoea/chlamydia/syphilis in men who have sex with men (MSM) taking HIV pre-exposure prophylaxis (PrEP). Fifty-nine MSM taking HIV PrEP were enrolled. In this crossover trial, participants received 3 months of daily Listerine followed by 3 months of placebo mouthwash or vice versa. Oropharyngeal swabs were taken at baseline and after 3 months use of each mouthwash. DNA was extracted for shotgun metagenomic sequencing (Illumina Inc.). Non-host reads were taxonomically classified with MiniKraken and Bracken. The alpha and beta diversity indices were compared between baseline and after each mouthwash use. Differentially abundant bacterial taxa were identified using ANOVA-like differential expression analysis.Results. Streptococcus was the most abundant genus in most samples (n = 103, 61.7 %) with a median relative abundance of 31.5% (IQR 20.6-44.8), followed by Prevotella [13.5% (IQR 4.8-22.6)] and Veillonella [10.0% (IQR 4.0-16.8)]. Compared to baseline, the composition of the oral microbiome at the genus level (beta diversity) was significantly different after 3 months of Listerine (P = 0.006, pseudo-F = 2.29) or placebo (P = 0.003, pseudo-F = 2.49, permutational multivariate analysis of variance) use. Fusobacterium nucleatum and Streptococcus anginosus were significantly more abundant after Listerine use compared to baseline.Conclusion. Listerine use was associated with an increased abundance of common oral opportunistic bacteria previously reported to be enriched in periodontal diseases, oesophageal and colorectal cancer, and systemic diseases. These findings suggest that the regular use of Listerine mouthwash should be carefully considered.

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.

Association between periodontal disease and oral squamous cell carcinoma: a systematic review and meta-analysis

To investigate the relation between periodontal disease (PD) and oral squamous cell carcinoma (OSCC) we systematically searched records published up to August 2022. Odds ratios (OR) and relative risk (RR) with 95% confidence intervals (95% CI) were estimated to evaluate this relation, then sensitivity analysis was performed accordingly. Begg's test and Egger's test were used to detect publication bias. Out of 970 papers from several databases, 13 studies were included. Summary estimates showed that PD was positively associated with the prevalence of OSCC (OR = 3.28, 95% CI: 1.87 to 5.74), especially for severe PD (OR = 4.23, 95% CI: 2.92 to 6.13). No evident publication bias was revealed. No increased OSCC risk among patients with PD was shown according to the combined results (RR = 1.50, 95% CI: 0.93 to 2.42). Patients with OSCC exhibited significant differences in alveolar bone loss, clinical attachment loss, and bleeding on probing, when compared with controls. The systematic review and meta-analysis suggested that there was a positive association between PD and prevalence of OSCC. However, according to the current evidence, a causal relation is unclear.

Is there an association between oral hygiene and head and neck cancer?

DATA SOURCES

PubMed, Web of Science, the Cochrane Library and Embase were utilised as databases from inception till November 2021.

STUDY SELECTION

The inclusion criteria consisted of cohort and case-control studies published in the English language, which dealt with diagnosed cases of head and neck cancer reporting survival, oral hygiene and comparative data. Studies pertaining to animal experiments along with case reports, conference proceedings, reviews, letters, editorials, errata and protocols were excluded.

DATA EXTRACTION AND SYNTHESIS

Data such as publication year, authors' names, country, sources, study groups, age, gender, participant number, education, alcohol, tobacco, study quality, cancer site and outcomes were extracted for each included study. A modified Newcastle-Ottawa Scale was utilized to evaluate the quality of these studies.

RESULTS

A total of forty-four studies were included, of which forty were case-control and four were cohort in nature. These comprised of a total of 52,863 patients of which 33,000 were devoid of head and neck cancer (HNC) while, 19,863 had a confirmed diagnosis of HNC. Oral hygiene and HNC were found to be associated.

CONCLUSIONS

Poor oral hygiene was concluded to be associated with HNC and the subsites thereof.

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.

Assessment of the association between periodontal disease and total cancer incidence and mortality: a meta-analysis

Background

Periodontal disease (PD) is a chronic inflammatory disease that leads to alveolar bone resorption and tooth loss. Many studies have reported the association between periodontal disease and various cancers including oral cancer, lung cancer, breast cancer and so on. However, there is still no specialized meta-analysis that assesses the association between periodontal disease and cancer incidence and mortality in-deepth. Thus, we conducted this meta-analysis.

Methods

This meta-analysis was registered with PROSPERO: CRD42020183497. We searched five online databases for observational studies about the association between periodontal disease and breast, prostate, lung and bronchial, colorectal, and total cancers by July 2020. Then we evaluated quality of the included studies by the Newcastle-Ottawa scale. Risk ratios (HRs) and their 95% confidence intervals (CIs) were pooled to evaluate the strength of the association between periodontal disease and four cancers, total cancer incidence and mortality. In addition, we analyzed heterogeneity by subgroup analysis and sensitivity analysis. Finally, we inspected publication bias by Begg's and Egger's tests.

Results

None of the studies included in this meta-analysis were of poor quality. PD is not only related to breast cancer incidence (HR = 1.26,95%CI [1.11-1.43], I ² = 75.8%, P = 0.000), but also connected with total cancer mortality (HR = 1.40,95%CI [1.24-1.58], I ² = 0.0%, P = 0.718). Subgroup analyses showed that study population, study design, dental status, follow-up period, adjustment for smoking partially explained the heterogeneity between studies. The results of Begg's test and Egger's test were consistent and indicated that there is no publication bias in this study.

Conclusion

In conclusion, this meta-analysis revealed a positive relationship between periodontal disease and breast cancer incidence and total cancer mortality. Further well-designed studies with specific inclusion and exclusion criteria are required to strengthen the conclusion of this meta-analysis. However, longer follow-up period, multi-center trials and even multinational studies are required to corroborate the results.

Intratumor microbiome in cancer progression: current developments, challenges and future trends

Cancer is a complicated disease attributed to multifactorial changes, which causes difficulties with treatment strategies. Various factors have been regarded as the main contributors, and infectious etiological factors have recently attracted interest. Several microbiomes contribute to carcinogenesis, cancer progression, and modulating cancer treatment by inducing cancerous epithelial cells and chronic inflammation. Most of our knowledge on the role of microbiota in tumor oncogenesis and clinical efficiency is associated with the intestinal microbiome. However, compelling evidence has also confirmed the contribution of the intratumor microbiome in cancer. Indeed, the findings of clinical tumor samples, animal models, and studies in vitro have revealed that many intratumor microbiomes promote tumorigenesis and immune evasion. In addition, the intratumor microbiome participates in regulating the immune response and even affects the outcomes of cancer treatment. This review summarizes the interplay between the intratumor microbiota and cancer, focusing on the contribution and mechanism of intratumor microbiota in cancer initiation, progression, and potential applications to cancer therapy.

Oral Health Status in Patients with Head and Neck Cancer before Radiotherapy: Baseline Description of an Observational Prospective Study

(1) Background: The general hypothesis that HNC patients show compromised oral health (OH) is generally accepted, but it is not evidence-based. The objective of this baseline report of a prospective observational study was to describe the oral health of a cohort of patients with HNC at the time of dental evaluation prior to radiotherapy (RT). (2) Materials and Methods: Two hundred and thirteen patients affected by HNC who had received an indication for RT were examined with the support of orthopantomography (OPT). The DMFt of all included subjects, their periodontal status and the grade of mouth opening were recorded. (3) Results: A total of 195 patients were ultimately included: 146/195 patients (74.9%) showed poor OH (defined as having a DMFt score ≥ 13 and severe periodontitis). The following clinical characteristics were correlated with poor oral health in the univariate analysis: tumor site, smoking habit and age of the patients (in decades); χ2 test, p < 0.05. (4) Conclusions: This study confirms that the OH of HNC patients is often compromised even before the beginning of cancer treatment and, consequently, highlights how important it is to promptly schedule a dental evaluation at the moment of diagnosis of the cancer.

Oral microbiota in the oral-genitourinary axis: identifying periodontitis as a potential risk of genitourinary cancers

Periodontitis has been proposed as a novel risk factor of genitourinary cancers: although periodontitis and genitourinary cancers are two totally distinct types of disorders, epidemiological and clinical studies, have established associations between them. Dysbiosis of oral microbiota has already been established as a major factor contributing to periodontitis. Recent emerging epidemiological evidence and the detection of oral microbiota in genitourinary organs indicate the presence of an oral-genitourinary axis and oral microbiota may be involved in the pathogenesis of genitourinary cancers. Therefore, oral microbiota provides the bridge between periodontitis and genitourinary cancers. We have carried out this narrative review which summarizes epidemiological studies exploring the association between periodontitis and genitourinary cancers. We have also highlighted the current evidence demonstrating the capacity of oral microbiota to regulate almost all hallmarks of cancer, and proposed the potential mechanisms of oral microbiota in the development of genitourinary cancers.

Mouthwash Use and the Risk of Oral, Pharyngeal, and Laryngeal Cancer. A Meta-Analysis

Objective: The main aim of this study was to test whether the use of mouthwash is associated with subtypes of squamous cell carcinoma of the head and neck (SCCHN) and to test the potential risk of SCCHN depending on the mouthwash use duration, frequency, or alcoholic content. Materials and methods: We performed a meta-analysis using Web of Science and Scopus databases to detect the risk change associated with mouthwash use depending on the alcohol content, duration and frequency of use, and anatomical location. We used a random-effects model with the Sidik–Jonkman estimator for effect size model measures. Results: We included 17 studies in the meta-analysis containing 17,085 cases and 20,032 controls. The risk difference for SCCHN between mouthwash users and non-users was minimal, with a value of −0.02 [−0.05, 0.01]. Alcoholic mouthwash use was associated with a minimal decrease in risk (of −0.01 [−0.07, 0.05]). Frequent usage of mouthwash was associated with a statistically significant risk increase for SCCHN but the risk increase was marginal (0.04, [0.01, 0.06]). Conclusions: Overall, our study failed to show a statistically significant correlation between mouthwash use and the risk of SCCHN. The only statistically significant correlation that we could identify was between frequent usage and SCCHN, potentially caused by prolonged contact between some constituents of mouthwash (possibly alcohol) and the oral epithelium.

Periodontitis as a risk factor for head and neck cancer

Background

Periodontitis may be associated with the development of head and neck cancer (HNC). A literature review was conducted to understand the possible association between them.

Material and Methods

Articles published in the PubMed database from January 1999 and May 2020 were retrieved. Limitations of the studies and biological mechanisms were discussed.

Results

A total of 4,232 articles were found. Of these, 13 were analyzed according to inclusion criteria. Most papers found some association between periodontitis and HNC, although differences in periodontal evaluation, sample size, study design and tumor sites were observed. Porphyromonas gingivalis appears to increase the chance of both diseases, and it may be one of their main potential risk factors. Genetic predisposition is increased by exposure to environmental factors which can directly induce epigenetic changes that contribute to these diseases.

Conclusions

Understanding the mechanisms related to periodontitis and HNC has increased, however, well-designed clinical studies are needed for better conclusions. Furthermore, the advent of multiple "omic" technologies will help comprehend their possible association.

Key words:Periodontitis, head and neck cancer, oral cancer, risk factors, biological factors.

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.

Oral and laryngeal HPV infection: Incidence, prevalence and risk factors, with special regard to concurrent infection in head, neck and genitals

This review focuses on the importance of oral and laryngeal HPV infection which is present in majority of sexually active individuals at least once in their lifetime. Despite testing, still little is known about prevalence rates, determinants and, especially, the concurrent HPV infection in head and neck, and genitals. The purpose of this review is to clarify some issues of oral HPV incidence, prevalence, and to demonstrate the difficulties in identification of asymptomatic oral HPV carriers. The main premise to take up this topic is the high and still increasing risk for development of oropharyngeal cancer, and potential benefit from screening strategies, education programs and HPV vaccination. Transmission of HPV to the oral cavity and oropharynx is hypothesized to occur mainly through sexual contact. The exposure of oropharyngeal mucosa to HPV infection with consequence of increased risk for oropharyngeal carcinoma depends on specific sexual behavior. Male gender, older age, race or ethnicity, oral hygiene and current cigarette smoking are independently associated with any prevalent oral HPV infection.

Efficacy of Essential Oil Mouthwashes With and Without Alcohol on the Plaque Formation: A Randomized, Crossover, Double-Blinded, Clinical Trial

BACKGROUND

Essential oil (EO) mouthwash has been considered as one of the effective chemical agents as an adjunct to mechanical plaque control, without adverse effects compared with chlorhexidine (pigmentation, changes of taste, and formation of supragingival calculus), which limits its continuous use. New EO alcohol-based has emerged with questions regarding contraindications for its daily use.

OBJECTIVE

To compare the efficacy of EO mouthwashes with and without alcohol on the early supragingival and subgingival plaque formation using a plaque-free zone score system.

METHODS

This study was a crossover, randomized, double-blind clinical trial. Eleven participants, totaling 396 sites of evaluation, remained 4 days with no mechanical oral hygiene control and only used EO mouthwash with (control) and without alcohol (test) during this period. The presence of the plaque-free zone was recorded every 24 hours. Friedman and Wilcoxon tests were used with a 5% significance level.

RESULTS

The control group showed a more significant number of buccal surfaces free of plaque at 48, 72, and 96 hours compared with the test group. Both groups presented satisfactory efficacy up to 72 hours with a significant difference in favor of the control group. The presence of subgingival plaque on both the proximal and free surfaces was significantly higher in the test group.

CONCLUSION

EO with alcohol presented better results in retarding the early supragingival and subgingival plaque formation compared with EO without alcohol.

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.

Risk factors of head and neck cancer mortality compared with those of all-cause and all-cancer mortalities

This study aimed to clarify the risk factors of head and neck cancer (HNC) mortality, relative to those of all-cause and all-cancer mortalities, using the Korean National Health Insurance Service-Health Screening Cohort (NHIS-HEALS) data set. Data from 238 HNC deaths, 14,769 all-cancer deaths, and 38,086 all-cause deaths were extracted during a median follow-up period of 9.5 years. Baseline characteristics were assessed via chi-square tests, t tests, and multivariable logistic regression. HNC mortality was found to be positively associated with male sex, past and current smoking habits, moderate-to-heavy alcohol consumption, and being underweight. In addition, serum gamma-glutamyltransferase level was found to be significantly elevated in cases of HNC mortality. In contrast, obesity, a history of diabetes, and fasting blood glucose levels were found to be inversely associated with overall HNC mortality. Among the HNC subtypes, mortality due to laryngeal cancer was most strongly associated with past and heavy cigarette smoking, and mortality due to oro-/hypopharyngeal cancer was most strongly associated with heavy alcohol consumption. The present study demonstrates that this nationwide, population-based NHIS-HEALS data set can provide useful information for health research and policy development.

Mouthwash With Alcohol and Oral Carcinogenesis: Systematic Review and Meta-analysis

BACKGROUND

It has been shown that the risk of developing oral cancer is closely related to the intensity and duration of exposure to alcohol and tobacco. Even so, the use of mouthwashes with alcohol in their compositions and the increased risk of oral cancer has been a source of controversy for decades.

OBJECTIVE

This study proposes a systematic review and a meta-analysis of the literature, to assess the possible relationship between the use of mouthwashes with alcohol and the development of oral and pharyngeal cancers.

MATERIALS AND METHODS

A systematic search was done using the Medline and PubMed databases. Exclusion criteria were as follows: articles published in languages other than English or Spanish, systematic reviews, and expert opinions. No limitations were used for publication date.

RESULTS

A total of 14 articles were obtained, 11 case-control studies and 3 clinical trials. Three case-control studies found no statistically significant evidence between the relationship of mouthwash use and oral cancer and the remaining 8 case-control studies found statistically significant evidence. The 3 clinical trials observed a relationship between the use of mouthwashes with alcohol and the possibility of developing cancer due to the genotoxicity and mutagenic capacity of alcohol in chronic contact with oral tissues and mucous membranes. The meta-analysis resulted in an OR = 1.480 and a P-value = .161 (95% CI: 0.855; P-value = 2.561) for the analysis of studies of cancer risk and consumption of mouthwashes with alcohol and OR = 1.057 0.364 (95% CI: 0.951; P-value = 1.174) for studies that related the risk of cancer and mouthwash use without taking into account the presence of alcohol.

CONCLUSIONS

There is no sufficient evidence to accept the proposition that the use of mouthwashes containing alcohol can influence the development of oral cancer.

A review of the influence of periodontal treatment in systemic diseases

The effects and consequences of periodontal diseases might not be confined to the oral cavity. A great body of evidence has arisen supporting the claim demonstrating an association with several systemic conditions and diseases. With different levels of evidence, an association between periodontal disease and cardiovascular disease, diabetes, psoriasis, rheumatoid arthritis, pregnancy outcomes and respiratory diseases has been established. However, the true nature of this association, if it is causal, still remains elusive. For a better understanding of the complex relationships linking different conditions, interventional studies now begin to focus on the possible outcomes of periodontal treatment in relation to the events, symptoms and biomarkers of several systemic disorders, assessing if periodontal treatment has any impact on them, hopefully reducing their severity or prevalence. Therefore, we proceeded to review the recent literature on the subject, attempting to present a brief explanation of the systemic condition or disease, what proposed mechanisms might give biological plausibility to its association with periodontal disease, and finally and more importantly, what data are currently available pertaining to the effects periodontal treatment may have. Raising awareness and discussing the possible benefits of periodontal treatment on overall systemic health is important, in order to change the perception that periodontal diseases are only limited to the oral cavity, and ultimately providing better and comprehensive care to patients.

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.

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.

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.

Transcriptome changes induced in vitro by alcohol-containing mouthwashes in normal and dysplastic oral keratinocytes

BACKGROUND

The role of alcohol-containing mouthwash as a risk factor for the development of oral cancer is a subject of conflicting epidemiological evidence in the literature despite alcohol being a recognised carcinogen. The aim of this study was to use in vitro models to investigate mechanistic and global gene expression effects of exposure to alcohol-containing mouthwash.

METHODS

Two brands of alcohol-containing mouthwash and their alcohol-free counterparts were used to treat two oral cell lines derived from normal (OKF6-TERT) and dysplastic (DOK) tissues. Genotoxicity was determined by Comet assay. RNA-seq was performed using the Ion Torrent platform. Bioinformatics analysis used R/Bioconductor packages with differential expression using DEseq2. Pathway enrichment analysis used EnrichR with the WikiPathways and Kegg databases.

RESULTS

Both cell lines displayed dose-dependent DNA damage in response to acute exposure to ethanol and alcohol-containing mouthwashes as well as alcohol-free mouthwashes reconstituted with ethanol as shown by Comet assay. The transcriptomic effects of alcohol-containing mouthwash exposure were more complex with significant differential gene expression ranging from >2000 genes in dysplastic (DOK) cells to <100 genes in normal (OKF6-TERT) cells. Pathway enrichment analysis in DOK cells revealed alcohol-containing mouthwashes showed common features between the two brands used including DNA damage response as well as cancer-associated pathways. In OKF6-TERT cells, the most significantly enriched pathways involved inflammatory signalling.

CONCLUSIONS

Alcohol-containing mouthwashes are genotoxic in vitro to normal and dysplastic oral keratinocytes and induce widespread changes in gene expression. Dysplastic cells are more susceptible to the transcriptomic effects of mouthwash.

Impact of oral hygiene on head and neck cancer risk in a Chinese population

BACKGROUND

Although the impact of oral hygiene on head and neck cancer risk has been investigated, few studies have been conducted among the Asian population.

METHODS

We conducted a multicenter case-control study to investigate this potential association. We performed unconditional multiple logistic regression models adjusted by potential confounders.

RESULTS

We observed an inverse association of frequency of dental visits with head and neck cancer risk, with an adjusted odds ratio (OR) of 3.70 (95% CI 2.51-5.45) for never dental visits compared with ≥1 time/year (Ptrend < .001). We also observed a positive association between the number of missing teeth and head and neck cancer risk, with an adjusted OR for ≥5 missing teeth compared with <5 missing teeth of 1.49 (95% CI 1.08-2.04). Combining multiple oral hygiene indicators, poor oral hygiene scores increased head and neck cancer risk.

CONCLUSION

Poor oral hygiene may increase head and neck cancer risk in the Chinese population. Therefore, improving oral hygiene may contribute to reducing the head and neck cancer risk in the Chinese population.

Prevalence and determinants of oral infection by Human Papillomavirus in HIV-infected and uninfected men who have sex with men

Background

Oral Human Papillomavirus (HPV) infection is rare in the general population but common in high-risk individuals. Recent data indicate that oral HPV is associated with the development of head and neck carcinomas. HPV16 infection, in particular, increases the risk of oropharyngeal cancer.

Methods

We evaluated oral HPV prevalence and determinants of infection in cancer-free HIV-infected and uninfected men who have sex with men (MSM) recruited among attendees of an STI/HIV centre. Oral rinse and gargles were collected using a mouthwash and analyzed with the Linear Array HPV Genotyping Test. Socio-demographic and behavioral data were collected through face-to-face interviews.

Results

Overall, 170 MSM participated: 98 HIV-uninfected and 72 HIV-infected (91.7% under cART). Oral HPV was detected in 17.3% and 27.8% of the subjects, respectively (p = 0.13). Non-carcinogenic HPVs were significantly more common among HIV-infected MSM (18.1% vs. 5.1%, p = 0.01). Prevalence of the HPV types included in the quadrivalent HPV vaccine was similar (6.1% vs. 8.3% for the HIV-negative and positive MSM, respectively, p = 0.76). HPV16 was the most frequent type in HIV-negative (5.1%), and HIV-positive individuals, in the latter group together with HPV18, 72 and 84 (4.2% each). Older age at first sex (AOR: 4.02, 95% CI: 1.17–13.86 for those older than 18 years of age at first intercourse, p = 0.027) and a higher lifetime number of receptive oral sex partners (AOR: 9.14, 95% CI: 2.49–33.62 for those with >50 compared to ≤50 partners, p<0.001) were determinants of oral HPV among HIV-infected MSM.

Conclusion

Oral HPV infection among MSM attending an urban STI center is very frequent compared to the general population. Sexual behavior appears to be the major determinant of infection among the HIV-infected individuals.

Oral health and human papillomavirus-associated head and neck squamous cell carcinoma

BACKGROUND

Indicators of poor oral health, including smoking, have been associated with increased risk of head and neck squamous cell carcinoma, especially oropharyngeal squamous cell carcinoma (OPSCC), yet few studies have examined whether this association is modified by human papillomavirus (HPV) status.

METHODS

Data from interviews and tumor HPV status from a large population-based case-control study, the Carolina Head and Neck Cancer Study (CHANCE), were used to estimate the association between oral health indicators and smoking among 102 HPV-positive patients and 145 HPV-negative patients with OPSCC and 1396 controls. HPV status was determined by p16INK4a (p16) immunohistochemistry. Unconditional, multinomial logistic regression was used to estimate odds ratios (ORs) for all oral health indictors adjusting for important covariates.

RESULTS

Routine dental examinations were associated with a decreased risk of both HPV-negative OPSCC (OR, 0.52; 95% confidence interval [CI], 0.35-0.76) and HPV-positive OPSCC (OR, 0.55; 95% CI, 0.36-.86). Tooth mobility (a proxy for periodontal disease) increased the risk of HPV-negative disease (OR, 1.70; 95% CI, 1.18-2.43) slightly more than the risk for HPV-positive disease (OR, 1.45; 95% CI, 0.95-2.20). Ten or more pack-years of cigarette smoking were strongly associated with an increased risk of HPV-negative OPSCC (OR, 4.26; 95% CI, 2.85-6.37) and were associated less with an increased risk of HPV-positive OPSCC (OR, 1.62; 95% CI, 1.10-2.38).

CONCLUSIONS

Although HPV-positive and HPV-negative HNSCC differ significantly with respect to etiology and tumorigenesis, the current findings suggest a similar pattern of association between poor oral health, frequency of dental examinations, and both HPV-positive and HPV-negative OPSCC. Future research is required to elucidate interactions between poor oral health, tobacco use, and HPV in the development of OPSCC. Cancer 2017;71-80. © 2016 American Cancer Society.

Pretreatment oral hygiene habits and survival of head and neck squamous cell carcinoma (HNSCC) patients

Background

The survival time of patients with head and neck squamous cell carcinoma (HNSCC) is related to health behavior, such as tobacco smoking and alcohol consumption. Poor oral health (OH), dental care (DC) and the frequent use of mouthwash have been shown to represent independent risk factors for head and neck cancerogenesis, but their impact on the survival of HNSCC patients has not been systematically investigated.

Methods

Two hundred seventy-six incident HNSCC cases recruited for the ARCAGE study were followed through a period of 6–10 years. Interview-based information on wearing of dentures, gum bleeding, teeth brushing, use of floss and dentist visits were grouped into weighted composite scores, i.e. oral health (OH) and dental care (DH). Use of mouthwash was assessed as frequency per day. Also obtained were other types of health behavior, such as smoking, alcohol drinking and diet, appreciated as both confounding and study variables. Endpoints were progression-free survival, overall survival and tumor-specific survival. Prognostic values were estimated using Kaplan-Meier analysis and Cox proportional hazards regression models.

Results

A good dental care score, summarizing annual dental visits, daily teeth cleaning and use of floss was associated with longer overall survival time (p = .001). The results of the Cox regression models similarly suggested a higher risk of tumor progression and shortened overall survival in patients with poor dental care, but the results lost their statistical significance after other types of health behavior had been controlled for. Frequent use of mouthwash (≥ 2 times/day) significantly increased the risk of tumor-specific death (HR = 2.26; CI = 1.19–4.32). Alcohol consumption and tobacco smoking were dose-dependently associated with tumor progression and shorter overall survival.

Conclusion

Frequent mouthwash use of ≥ 2 times/day seems to elevate the risk of tumor-specific death in HNSCC patients. Good dental care scores are associated with longer overall survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-016-0185-0) contains supplementary material, which is available to authorized users.

Periodontal disease and risk of all cancers among male never smokers: an updated analysis of the Health Professionals Follow-up Study

BACKGROUND

Periodontal disease has a direct impact on the immune response and has been linked to several chronic diseases, including atherosclerosis and stroke. Few studies have examined the association between periodontal disease and cancer.

PATIENTS AND METHODS

A total of 19 933 men reported being never smokers (of cigarette, pipes or cigars) in the Health Professionals' Follow-up Study. Periodontal disease status and teeth number were self-reported at baseline and during follow-up. All cancers were ascertained during 26 years of follow-up. Cox's proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) adjusting for risk factors.

RESULTS

A 13% increase in total cancer was observed among men reporting periodontitis at baseline, and a 45% increase in risk was observed among men with advanced periodontitis (periodontitis with <17 remaining teeth). Periodontitis was not associated with prostate cancer, colorectal cancer or melanoma, the three most common cancers in this cohort of never smokers, but a 33% increase in risk was observed for smoking-related cancers (lung, bladder, oropharnygeal, esophageal, kidney, stomach and liver cancers; HR = 1.33, 95% CI 1.07-1.65). Men with advanced periodontitis had an HR of 2.57 (95% CI 1.56-4.21; P = 0.0002) for smoking-related cancers, compared with men who did not have periodontitis and had 17 teeth or more. Advanced periodontitis was associated with elevated risks of esophageal and head and neck cancers (HR = 6.29, 95% CI 2.13-18.6; based on five cases with advanced periodontitis) and bladder cancer (HR = 5.06, 95% CI 2.32-11.0; based on nine cases with advanced periodontitis).

CONCLUSIONS

Advanced periodontitis was associated with a 2.5-fold increase in smoking-related cancers among never smokers. Periodontitis may impact cancer risk through system immune dysregulation. Further studies need to examine the immune impact of advanced periodontitis on cancer, especially for cancers known to be caused by smoking.

Oral health status and dental care behaviours of head and neck cancer patients: a cross-sectional study in an Austrian tertiary hospital

OBJECTIVES

This study aimed to assess the oral health status and dental care behaviours of patients treated for head and neck squamous cell carcinoma (HNSCC) in an Austrian tertiary hospital.

MATERIALS AND METHODS

Dental care behaviours, oral hygiene level, caries, and periodontal parameters were assessed in 48 patients treated for HNSCC >6 months ago.

RESULTS

Only 52 % requested a dental check-up after HNSCC diagnosis and prior to treatment, and of those, 80 % received some type of dental treatment. At time-point of clinical examination, 69 % of the patients had consulted a dentist within the last year, but 88 % still needed dental treatment; 75 % had at least one tooth with caries and 78 % had moderate to severe periodontitis.

CONCLUSION

Although it was recommended, only half of the patients did consult a dentist prior to HNSCC treatment and oral health appeared, in general, low prioritized.

CLINICAL RELEVANCE

About 90 % of the current group of head and neck squamous cell carcinoma cancer patients presented large treatment needs, both in regard with caries and periodontal disease, about 20 months after cancer treatment.

Oral health, dental care and mouthwash associated with upper aerodigestive tract cancer risk in Europe: the ARCAGE study

OBJECTIVE

We aimed to assess the association of oral health (OH), dental care (DC) and mouthwash with upper-aerodigestive tract (UADT) cancer risk, and to examine the extent that enzymes involved in the metabolism of alcohol modify the effect of mouthwash.

MATERIALS AND METHODS

The study included 1963 patients with incident cancer of the oral cavity, oropharynx, hypopharynx, larynx or esophagus and 1993 controls. Subjects were interviewed about their oral health and dental care behaviors (which were converted to scores of OH and DC respectively), as well as smoking, alcohol drinking, diet, occupations, medical conditions and socio-economic status. Blood samples were taken for genetic analyses. Mouthwash use was analyzed in relation to the presence of polymorphisms of alcohol-metabolizing genes known to be associated with UADT. Adjusted odds ratios (ORs) and 95%-confidence intervals [CI] were estimated with multiple logistic regression models adjusting for multiple confounders.

RESULTS

Fully adjusted ORs of low versus high scores of DC and OH were 2.36[CI=1.51-3.67] and 2.22[CI=1.45-3.41], respectively, for all UADT sites combined. The OR for frequent use of mouthwash use (3 or more times/day) was 3.23[CI=1.68-6.19]. The OR for the rare variant ADH7 (coding for fast ethanol metabolism) was lower in mouthwash-users (OR=0.53[CI=0.35-0.81]) as compared to never-users (OR=0.97[CI=0.73-1.29]) indicating effect modification (pheterogeneity=0.065) while no relevant differences were observed between users and non-users for the variant alleles of ADH1B, ADH1C or ALDH2.

CONCLUSIONS

Poor OH and DC seem to be independent risk factors for UADT because corresponding risk estimates remain substantially elevated after detailed adjustment for multiple confounders. Whether mouthwash use may entail some risk through the alcohol content in most formulations on the market remains to be fully clarified.

Relationship between head and neck cancer therapy and some genetic endpoints

Head and neck cancer (HNC) is the sixth most common human malignancy worldwide. The main forms of treatment for HNC are surgery, radiotherapy (RT) and chemotherapy (CT). However, the choice of therapy depends on the tumor staging and approaches, which are aimed at organ preservation. Because of systemic RT and CT genotoxicity, one of the important side effects is a secondary cancer that can result from the activity of radiation and antineoplastic drugs on healthy cells. Ionizing radiation can affect the DNA, causing single and double-strand breaks, DNA-protein crosslinks and oxidative damage. The severity of radiotoxicity can be directly associated with the radiation dosimetry and the dose-volume differences. Regarding CT, cisplatin is still the standard protocol for the treatment of squamous cell carcinoma, the most common cancer located in the oral cavity. However, simultaneous treatment with cisplatin, bleomycin and 5-fluorouracil or treatment with paclitaxel and cisplatin are also used. These drugs can interact with the DNA, causing DNA crosslinks, double and single-strand breaks and changes in gene expression. Currently, the late effects of therapy have become a recurring problem, mainly due to the increased survival of HNC patients. Herein, we present an update of the systemic activity of RT and CT for HNC, with a focus on their toxicogenetic and toxicogenomic effects.

High-risk HPV types and head and neck cancer

Although HPV16 has been strongly implicated in oropharyngeal carcinogenesis, the role of other high-risk HPV types in the etiology of head and neck cancer remains unclear. To date, few data exist addressing the nature of the association between antibodies to oncogenic proteins of non-HPV16 HPVs in relation to head and neck cancer. We examined the relationship between multiple HPV types (HPV6, 11, 16, 18, 31, 33, 45, 52, 58) and head and neck squamous cell carcinoma (HNSCC) in a large population-based case-control study (1069 cases and 1107 controls). Serological measures for HPV types included antibodies to L1, E6 and/or E7. In a secondary analysis, we excluded HPV16 seropositive subjects to examine independent associations with other high-risk HPVs. All analyses were adjusted for age, race, sex, education, smoking and alcohol consumption. Statistically significant associations were observed for HPV16, 18, 33 and 52 and risk of HNSCC after mutually adjusting for HPV types. Among HPV16 seronegative subjects, elevated risks of HNSCC were observed for HPV18 E6 (OR = 4.19, 95% CI = 1.26-14.0), HPV33 E6 (OR = 7.96, 95% CI = 1.56-40.5) and HPV52 E7 (OR = 3.40, 95% CI = 1.16-9.99). When examined by tumor type, associations with HPV18 and HPV33 remained statistically significant for oropharyngeal cancer, and HPV52 was associated with oral cancer. In addition, magnitude of associations for HNSCC increased markedly with increasing number of seropositive high-risk HPV infections. High-risk HPV types, other than HPV16, are likely to be involved in the etiology of HNSCC.