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

The relationship between periodontal disease and cancer: Insights from a Systematic Literature Network Analysis

This paper investigates the relationship between periodontal disease and various cancer types. It provides a comprehensive overview of the existing knowledge about the interaction between periodontal disease and carcinogenesis, explores the underlying biological mechanisms of this connection, and consider the impact of these findings on healthcare practices and future research directions. Utilizing Systematic Literature Network Analysis, which combines bibliometric analysis with Systematic Literature Review, this study analyzes 164 documents from 2000 to 2023. Focus is placed on the 38 most globally cited papers, enabling a targeted and comprehensive analysis of the predominant research within this scope. This review highlights that colorectal, oral, pancreatic, lung, and gastrointestinal cancers have consistent associations with periodontal disease. On the other hand, hematological, breast and prostate cancers show associations with periodontal disease, but these links are less pronounced and more variable, indicating the need for targeted research in these domains. These insights emphasize the necessity for a multidisciplinary healthcare approach, recognizing the systemic implications of periodontal disease.

The role of periodontitis in cancer development, with a focus on oral cancers

Periodontitis is a severe gum infection that begins as gingivitis and can lead to gum recession, bone loss, and tooth loss if left untreated. It is primarily caused by bacterial infection, which triggers inflammation and the formation of periodontal pockets. Notably, periodontitis is associated with systemic health issues and has been linked to heart disease, diabetes, respiratory diseases, adverse pregnancy outcomes, and cancers. Accordingly, the presence of chronic inflammation and immune system dysregulation in individuals with periodontitis significantly contributes to the initiation and progression of various cancers, particularly oral cancers. These processes promote genetic mutations, impair DNA repair mechanisms, and create a tumor-supportive environment. Moreover, the bacteria associated with periodontitis produce harmful byproducts and toxins that directly damage the DNA within oral cells, exacerbating cancer development. In addition, chronic inflammation not only stimulates cell proliferation but also inhibits apoptosis, causes DNA damage, and triggers the release of pro-inflammatory cytokines. Collectively, these factors play a crucial role in the progression of cancer in individuals affected by periodontitis. Further, specific viral and bacterial agents, such as hepatitis B and C viruses, human papillomavirus (HPV), Helicobacter pylori (H. pylori), and Porphyromonas gingivalis, contribute to cancer development through distinct mechanisms. Bacterial infections have systemic implications for cancer development, while viral infections provoke immune and inflammatory responses that can lead to genetic mutations. This review will elucidate the link between periodontitis and cancers, particularly oral cancers, exploring their underlying mechanisms to provide insights for future research and treatment advancements.

Two-sample Mendelian randomization analysis of the relationship between periodontitis and risk of upper gastrointestinal cancers

PURPOSE

The aim of the present study is to explore the possible association between periodontitis and upper gastrointestinal (UGI) cancers, including esophageal and gastric cancers, utilizing the Mendelian randomization method.

METHODS

In this research, we utilized the Mendelian randomization method to examine the causal association between periodontitis and UGI cancers. Genome-wide association studies data for periodontitis were obtained from the Gene-Lifestyle Interactions in Dental Endpoints consortium, while UGI cancers' data were accessed from FinnGen's Biobank. After rigorously screening instrumental variables for periodontitis, we analyzed them with UGI cancers primarily using the inverse variance weighted. Finally, to identify outliers, the results were subjected to a leave-one-out sensitivity analysis.

RESULTS

Inverse variance weighted (fixed effect) results revealed that periodontitis is a risk factor for gastric cancer (OR = 1.7735, 95% CI: 1.1576 to 2.7170, P = 0.0085). As for esophageal cancer, no statistically significant correlation was observed. Furthermore, no outliers were detected in any of the results.

CONCLUSION

Our two-sample Mendelian randomization study obviously demonstrates a significant positive association between periodontitis and gastric cancer, while no statistically significant correlation was found for esophageal cancer.

Periodontitis and non-communicable diseases in a Brazilian population, a cross-sectional study, Vila Velha-ES, Brazil

BACKGROUND

The objective of this study was to examine the hypothesis that periodontal disease is associated with chronic non-communicable diseases.

METHODS

In this cross-sectional study, we evaluated the periodontal health condition of the population, based on the community periodontal index, as well as the number of missing teeth and the presence of systemic health conditions. We quantified the association between oral health and the presence of chronic diseases using simple logistic regression, adjusting for confounding factors including age, smoking, and overweight.

RESULTS

The study population consisted of 334 volunteers, aged between 19 and 81 years. In patients over 45 years old, periodontal disease was found to be significantly associated with hypertension and diabetes. Furthermore, in female patients, periodontal disease was significantly associated with hypertension, diabetes, and cancer.

CONCLUSION

Our findings indicate that periodontal disease is positively and significantly associated with both arterial hypertension and diabetes, independent of potential confounding factors.

Genetic and environmental contributions for the relationship between tooth loss and oral potentially malignant disorders and oral squamous cell carcinoma

BACKGROUND

To investigate the association between tooth loss and oral potentially malignant disorders and oral squamous cell carcinoma, focusing on epidemiological factors and genetic variants.

METHODS

Case-control study, including histologically confirmed oral potentially malignant disorders and oral squamous cell carcinoma cases and healthy controls. Unadjusted and adjusted odds ratios for this association were calculated. Single-nucleotides polymorphisms were tested for individuals with and without missing teeth.

RESULTS

Case individuals were more edentulous while controls had fewer missing teeth (p = 0.006). There was an increased risk for the outcomes associated with edentulism (OR = 6.95, p = 0.000), even after adjustments for educational level (OR = 4.7, p = 0.034) and smoking habits (OR = 5.01, p = 0.022). Among individuals with tooth loss, rs1533767 (WNT11), rs3923087, and rs11867417 (AXIN2) were associated with the outcomes (OR = 1.67, p = 0.03, OR = 0.53, p = 0.05, and OR = 0.42, p = 0.00, respectively).

CONCLUSIONS

Tooth loss could increase the risk for oral potentially malignant disorders and oral squamous cell carcinoma.

Oral anaerobe bacteria-a common risk for cardiovascular disease and mortality and some forms of cancer?

This review explores the results of research on oral health concerning cardiovascular diseases and some forms of cancer and is based on results from published systematic reviews and some studies. The research results will have a strong focus on exploring the relationship between different aspects of oral infections. The relationship between oral health parameters, cardiovascular diseases (CVD), and certain cancers was examined from different angles, including prospective analyses, in a population-based health study in Oslo from the year 2000 (Oslo II study). A major finding was that low levels of antibodies to the oral anaerobe Tannerella forsythia predict both CVD mortality in men with a history of myocardial infarction and incidence of bladder cancer in a random sample of men in the study. Low levels of antibodies to Treponea denticola predict the incidence of bladder and colon cancer in a random sample of men in the study. Both anaerobe bacteria are part of the so-called red complex of bacteria in chronic periodontitis together with Pophyromonas gingivalis. These three bacteria have different properties and are causal in chronic periodontitis. They migrate into the local tissues by adhering to the oral epithelium, break down soft and hard tissues, and spread via the circulation to organs distant from the mouth. This paper will give an overview of which oral health measures have been explored and associated with different CVD and cancer diagnoses and what scientific literature supports or contravenes our hypothesis. The oral microbiome is described with the most relevant bacteria related to microbiology, serum, autopsies, and associated causes such as alcohol. There will be a mention of the possibilities and limitations of different study designs. There seems to be a causal relationship between oral anaerobe bacteria and systemic diseases regulated by the immune system. This is seen alongside other well-known risk factors, especially for CVD. The prospective finding of a relation to the incidence of certain cancers and CVD is particularly intriguing. However, further research is needed to determine the biological mechanisms underpinning these associations.

Development and initial validation of the Comprehensive Geriatric Oral Health Assessment Tool

OBJECTIVES

Improving the oral health of the elderly is crucial to improving their general health and quality of life. To reach this goal, it is necessary to start with a comprehensive oral health assessment and a detailed treatment plan. The aim of this study was, therefore, to develop a comprehensive Oral Health Assessment Tool for the geriatric population.

MATERIAL AND METHODS

Following a panel of experts' consultation, a clinical form and a self-assessment questionnaire were developed, encompassing eight domains: dental caries, periodontal diseases, partial and complete edentulism, oral soft tissue lesions, occlusion, xerostomia, temporomandibular joints, and oral or oral prostheses hygiene. Subsequently, a pilot study was conducted to appraise the clinical form and questionnaire involving 84 residents of an Iranian nursing home. After securing ethics approval, both the qualitative and quantitative aspects of the self-assessment questions' validity and reliability were assessed, and specificity and sensitivity were calculated.

RESULTS

The mean age of the participants was 69.8 (±4.1) years, and 86% had less than 12 years of education. The questions regarding the number of remaining teeth and the number of decayed teeth had the highest sensitivity (97% and 88%), respectively. Questions regarding the presence of periodontitis and gingivitis had the highest specificity (both 100%).

CONCLUSIONS

A Comprehensive Geriatric Oral Health Assessment Tool has been developed and its validity and reliability evaluated in a pilot study. It should now be further evaluated in larger studies.

ASSOCIATION OF ORAL MICROBIOTA AND PERIODONTAL DISEASE WITH LUNG CANCER: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVES

Evidence of oral microbiota perturbations has been accumulated for lung cancers. This review focused on the oral microbiota alterations in population suffering from lung cancer. In addition, we also discussed conflicting data about the association between oral microbiota dysbiosis and risk of lung cancer.

METHODS

A systematic search was conducted in Medline, Embase, PubMed, and Cochrane Library databases. The studies evaluated diversity and abundance of oral microbes in healthy and lung cancer individuals as well as association of periodontal disease and pathogens with lung cancer. Of 3559 studies, 28 included studies were performed in qualitative analysis, and 25 studies were used in meta-analyses for quantitative assessment. Heterogeneity was analyzed by using I² and chi-squared Q test statistics. Statistical analyses were performed by using the RevMan 5.4 software.

RESULTS

Compared with the control, lung cancer patients had lower alpha diversity (Shannon: SMD = -0.54; 95% CI, -0.90 to -0.19; P < .01, I2 = 71%). In nested case-control studies, individuals with decreased alpha diversity tended to have an increased risk of lung cancer (observed species: HR = 0.90; 95% CI, 0.85-0.96; P < .01, I2 = 0%; Shannon: HR = 0.89; 95% CI, 0.83-0.95; P < .01, I2 = 0%). Overall, no strong evidence of association of relative abundance with specific oral microbes with lung cancers was found because of inconsistent data. No associations were found between periodontal pathogens and lung cancer risk (red complex: HR = 1.12, 95% CI: 0.42-3.02, P = .82, I2 = 62%; orange complex: HR =1.77, 95% CI: 0.78-3.98, P = .17, I2 = 36%), expect for Fusobacterium nucleatum (HR = 2.27, 95% CI: 1.13-4.58, P = .02, I2 = 0%). The positive association of periodontal disease with lung cancer risk was found (HR = 1.58, 95% CI: 1.25-2.00, P < .001, I2= 0%) with increase of periodontal diseases severity (HR = 2.39, 95% CI: 1.57-3.66, P < .001, I2 = 0%). However, such association was not found in never-smoker participants (HR = 1.00, 95% CI: 0.76-1.31, P = .37, I2= 7%).

CONCLUSIONS

Lower alpha diversity of oral microbiome may be associated with a greater risk of lung cancer and might serve as a predictive signal of lung cancer risk. There was no strong evidence of relative abundance of oral microbial taxa and periodontal pathogens in lung cancer patients. Fusobacterium nucleatum might be a potential microbial candidate of biomarkers in lung cancer. Periodontal disease may be positively associated with lung cancer risk by confounding of smoking, but not an independent risk factor.

Phyllanthus emblica fruits: a polyphenol-rich fruit with potential benefits for oral management

The fruit of Phyllanthus emblica Linn., which mainly grows in tropical and subtropical regions, is well-known for its medicine and food homology properties. It has a distinctive flavor, great nutritional content, and potent antioxidant, anti-inflammatory, anti-cancer and immunoregulatory effects. According to an increasing amount of scientific and clinical evidence, this fruit shows significant potential for application and development in the field of oral health management. Through the supplementation of vitamins, superoxide dismutase (SOD) and other nutrients reduce virulence expression of various oral pathogens, prevent tissue and mucosal damage caused by oxidative stress, etc. Phyllanthus emblica fruit can promote saliva secretion, regulate the balance of the oral microecology, prevent and treat oral cancer early, promote alveolar bone remodeling and aid mucosal wound healing. Thus, it plays a specific role in the prevention and treatment of common oral disorders, producing surprising results. For instance, enhancing the effectiveness of scaling and root planing in the treatment of periodontitis, relieving mucosal inflammation caused by radiotherapy for oral cancer, and regulating the blood glucose metabolism to alleviate oral discomfort. Herein, we systematically review the latest research on the use of Phyllanthus emblica fruit in the management of oral health and examine the challenges and future research directions based on its chemical composition and characteristics.

2022 Update on Prostate Cancer Epidemiology and Risk Factors-A Systematic Review

CONTEXT

Prostate cancer (PCa) is one of the most common cancers worldwide. Understanding the epidemiology and risk factors of the disease is paramount to improve primary and secondary prevention strategies.

OBJECTIVE

To systematically review and summarize the current evidence on the descriptive epidemiology, large screening studies, diagnostic techniques, and risk factors of PCa.

EVIDENCE ACQUISITION

PCa incidence and mortality rates for 2020 were obtained from the GLOBOCAN database of the International Agency for Research on Cancer. A systematic search was performed in July 2022 using PubMed/MEDLINE and EMBASE biomedical databases. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and was registered in PROSPERO (CRD42022359728).

EVIDENCE SYNTHESIS

Globally, PCa is the second most common cancer, with the highest incidence in North and South America, Europe, Australia, and the Caribbean. Risk factors include age, family history, and genetic predisposition. Additional factors may include smoking, diet, physical activity, specific medications, and occupational factors. As PCa screening has become more accepted, newer approaches such as magnetic resonance imaging (MRI) and biomarkers have been implemented to identify patients who are likely to harbor significant tumors. Limitations of this review include the evidence being derived from meta-analyses of mostly retrospective studies.

CONCLUSIONS

PCa remains the second most common cancer among men worldwide. PCa screening is gaining acceptance and will likely reduce PCa mortality at the cost of overdiagnosis and overtreatment. Increasing use of MRI and biomarkers for the detection of PCa may mitigate some of the negative consequences of screening.

PATIENT SUMMARY

Prostate cancer (PCa) remains the second most common cancer among men, and screening for PCa is likely to increase in the future. Improved diagnostic techniques can help reduce the number of men who need to be diagnosed and treated to save one life. Avoidable risk factors for PCa may include factors such as smoking, diet, physical activity, specific medications, and certain occupations.

The effect of oral bacterial infection on DNA damage response in host cells

Maintaining and transferring intact genomes from one generation to another plays a pivotal role in all living organisms. DNA damage caused by numerous endogenous and exogenous factors must be adequately repaired, as unrepaired and accumulated DNA mutations can cause severe deleterious effects, such as cell death and cancer. To prevent adverse consequences, cells have established DNA damage response mechanisms that address different forms of DNA damage, including DNA double-strand breaks, mismatches, nucleotide excision, and base excision. Among several sources of exogenous DNA damage, bacterial infections cause inflammation in the host, generating reactive oxygen species (ROS) and causing oxidative DNA damage. Recent studies have revealed the importance of the oral microbiome in inflammation and several systemic host diseases. Dysbiosis of oral bacteria can induce chronic inflammation, which enhances ROS-induced DNA damage, and improperly repaired damage can lead to carcinogenesis. This review describes the various DNA repair pathways that are affected by chronic inflammation and the discovery of the DNA damage response induced by oral bacteria such as Porphyromonas gingivalis and Fusobacterium nucleatum.

Insights into the Human Microbiome and Its Connections with Prostate Cancer

The human microbiome represents the diversity of microorganisms that live together at different organ sites, influencing various physiological processes and leading to pathological conditions, even carcinogenesis, in case of a chronic imbalance. Additionally, the link between organ-specific microbiota and cancer has attracted the interest of numerous studies and projects. In this review article, we address the important aspects regarding the role of gut, prostate, urinary and reproductive system, skin, and oral cavity colonizing microorganisms in prostate cancer development. Various bacteria, fungi, virus species, and other relevant agents with major implications in cancer occurrence and progression are also described. Some of them are assessed based on their values of prognostic or diagnostic biomarkers, while others are presented for their anti-cancer properties.

Exploring the oral microbiome: an updated multidisciplinary oral healthcare perspective

The oral cavity is home to diverse microbial content, collectively called as the oral microbiome. The latest technological advancements have unraveled the intricacies of the oral microbiome.  It can be of great importance for oral health care givers to know the fundamentals and latest developments in the field of the oral microbiome, as oral dysbiosis is associated with many common diseases frequently seen and managed by them. These diseases include dental caries, periodontitis, mucosal diseases (such as oral leukoplakia, oral lichen planus, and systemic lupus erythematosus), oral cancers, and even co-infections related to the current COVID-19 pandemic. The emergence of new genomic and molecular biology methodologies has been pivotal for understanding the role of the human microbiome in health and disease. The current review compiles oral microbiome in health and disease with a multidisciplinary dental approach. The insight into the oral microbiome, which is provided dental specialty wise in the current article will initiate and guide researchers of various disciplines in developing microbiome-based therapeutic or prophylactic management strategies, managing public health challenges by microbiome-based boarder interventions and divert resources for preserving and achieving a balanced oral microbiome.

Could there be an interplay between periodontal changes and pancreatic malignancies?

The term "periodontal disease" refers to a group of chronic inflammatory illnesses caused by specific microorganisms from subgingival biofilm, that affect the tooth-supporting tissues. Recent research has also shown that periodontal infection plays a role in aggravating systemic disease states at distal sites, reinforcing the significance of the oral cavity for general health. Additionally, it has been suggested that gastroenterological malignancies may be promoted by hematogenous, enteral or lymphatic translocation of periopathogens. In the past 25 years, the global burden of pancreatic cancer (PC) has more than doubled, making it one of the major causes of cancer-related mortality. Periodontitis has been linked to at least 50% increased risk of PC and it could be considered a risk factor for this malignancy. A recent study performed on 59000 African American women with a follow up of 21 years showed that participants who had poor dental health had higher chances of PC. The findings, according to researchers, might be related to the inflammation that some oral bacteria trigger. Regarding the mortality of PC, periodontitis considerably raises the chance of dying from PC. Microbiome alterations in the gut, oral cavity and pancreatic tissues of PC patients occur when compared to healthy flora, demonstrating a link between PC and microecology. Inflammation may also contribute to PC development, although the underlying pathway is not yet known. The function of the microbiome in PC risk has drawn more focus over the last decade. Future risk of PC has been linked to the oral microbiome, specifically increased levels of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans and decreased relative abundance of Leptotrichia and Fusobacteria, suggesting that it may have an impact on the inflammatory condition by expanding, altering, and regulating the commensal microbiome. Patients who received periodontal treatment had significantly decreased incidence rate ratios for PC. By analyzing patterns in the microbiome composition throughout PC development and establishing strategies to enhance the cancer-associated microbial system, we can increase the efficacy of therapy and eventually find an application for the microbial system. The development of immunogenomics and gut micro-genomics in the life sciences will result in a significant advancement in our understanding of how microbial systems and immunotherapy interact, and it may also have intriguing therapeutic implications for extending the lifetime of PC patients.

Association between tooth loss and risk of occurrence of oral cancer - A systematic review and meta-analysis

Background

Periodontitis, the second most common reason for tooth loss in adults, is a chronic inflammatory condition that increases the prevalence of cancer by inhibiting apoptosis and promoting tumor cell growth. However, it is still debatable if tooth loss is an important risk factor in oral cancer (OC). The aim of this systematic review is to analyze the relationship between tooth loss and the probability of developing head-and-neck cancer and also to see if there is an association between tooth loss, periodontitis, and the risk of OC.

Materials and Methods

Studies that depicted a link between tooth loss and OC (till 2017) were searched from online databases accompanied by a thorough manual search of relevant journals. Data were collected from eligible studies, and meta-analysis was carried out using the Meta-Analysis software. The effect of various inclusions was assessed by sensitivity and subgroup analysis. Publication bias was also evaluated.

Results

The meta-analysis consisted of 15 publications. When the number of teeth lost was counted, there was significant variability (I2 = 98.7%, P = 0.0001). When more than 15 teeth were missing in a subgroup analysis, there was a 2.4 times greater risk of OC (odds ratio: 2.496, 95% confidence interval [CI] = 2.067-3.015, P = 0.001) with no heterogeneity (I2 = 0.00%, 95% CI for I2 = 0.00-68.98). Subgroup analysis revealed that there was no evidence of publication bias.

Conclusion

It was concluded that tooth loss can increase the OC risk by nearly 2 folds. However, large-scale population-based studies are needed to substantiate the findings.

Modifiable risk factors for the development and progression of periodontal tissue diseases

In this review, an analysis of modifiable risk factors for the development and progression of periodontal tissue diseases was carried out. The review highlights the data on the relationship of periodontal infection, tobacco smoking, diabetes mellitus, cardiovascular disease, drug-induced periodontal tissue damage, stress, and obesity with the risk of developing and progression of periodontal tissue diseases. A rather detailed analysis of the mechanisms of pathogenic influence of the microflora of the oral cavity, including in the subgingival plaque, was carried out. The mechanisms of the pathological effect of smoking on the state of periodontal tissues are described. Data on the effect of periodontal treatment on glycemic control in patients with diabetes mellitus are presented. The article emphasizes the importance of the presence of periodontal diseases as a risk factor for cardiovascular and cerebrovascular diseases, describes the mechanisms of the mutual influence of cardiovascular pathology and the inflammatory process in the periodontium. In addition, the article presents the possibilities of the iatrogenic effect of systemic drugs on the state of periodontal tissues. The data on the influence of stress loads on the development of dental diseases are presented. The review article describes in detail the mechanisms of influence of overweight and obesity on the risks of development and progression of periodontal tissue diseases. Based on the results of the scientific research publications presented in the article, it can be stated that not only the dentist, but also doctors of other specialties need to work to change the modifiable risk factors for the development and progression of periodontal diseases.

Prevalence of cancer in relation to signs of periodontal inflammation

We investigated the associations between periodontal inflammation (gingivitis and periodontitis) and all-kind malignancies, specifically breast and prostate cancer, in a cohort followed-up for 30 years. The study hypothesis was based on the oral inflammation vs. systemic health paradigm. A sample of 2,168 subjects from an original cohort of 105,718 individuals from the greater Stockholm area in Sweden that had been followed since 1985 was investigated. Swedish national health registers were used in the study. Chi-square tests and logistic multiple regression analyses were conducted. The results showed that periodontitis was significantly associated with any cancer after adjusting for gender, age, income, and education (p = 0.015). The probability of getting cancer increased on average by 38% if the patient had periodontitis vs. had not; the odds ratio was 1.380 (95% confidence interval l.066-1.786). No significant association was observed between periodontitis and breast cancer (p = 0.608), while the association between periodontitis and prostate cancer tended towards significance (p = 0.082). However, no statistically significant difference was found between the observed and the calculated distribution of any cancer in gingivitis groups (p = 0.079). Thus, the study hypothesis was partly confirmed by showing a statistically significant association between periodontitis and any cancer.

Evolving evidence for relationships between periodontitis and systemic diseases: Position paper from the Canadian Dental Hygienists Association

AIM

The aim of this position paper is to investigate the current state of the evidence for proposed associations between periodontitis and rheumatoid arthritis, Alzheimer's disease, obesity, inflammatory cancers, and renal disease using a narrative review approach. This is the last of a series of 5 position papers from the Canadian Dental Hygienists Association (CDHA) on the relationship between periodontitis and systemic conditions.

METHODS

Individual literature searches were conducted for each of the 5 proposed linkages and limited to human studies, with a preference for systematic reviews (SRs) and prospective studies, in the English language, published between 2015 and 2021, focused on associations between 1) periodontitis and rheumatoid arthritis; 2) periodontitis and Alzheimer's disease/cognitive impairment; 3) periodontitis and obesity; 4) periodontitis and inflammatory cancers; and 5) periodontitis and chronic kidney disease. Databases searched were PubMed, MEDLINE/OVID, CINAHL, Scopus, Cochrane Registry of Systematic Reviews, and Web of Science.

RESULTS

A total of 39 papers were selected for discussion, including 6 SRs for rheumatoid arthritis; 7 SRs for Alzheimer's disease/cognitive impairment; 11 SRs, 1 meta-review of SRs, and 1 population-based cohort study for obesity; 9 SRs for inflammatory cancers; and 4 SRs for kidney disease.

CONCLUSIONS

The evidence for the 5 proposed associations varied in strength, with obesity being most strongly associated with periodontal disease. More robust studies are recommended to clarify the exact nature of these associations.

Is Periodontitis a Risk Factor for Lung Cancer? A Meta-Analysis and Detailed Review of Mechanisms of Association

Background

Numerous studies have explored the correlation of periodontal disease (PD) with the risk of lung cancers, but the findings were inconsistent. Therefore, we did a meta-analysis to ascertain the correlation of PD with the risk of incident lung cancer.

Methods

The authors searched relevant studies in databases (PubMed, Web of Science, Scopus, Embase, and MEDLINE) till November 2020. We registered the study at the International database of Prospectively Registered Systemic Reviews under the CRD42020198119. The summary relative risk (RR) along with a 95% confidence interval (CI) was calculated using fixed-effects models.

Results

Twelve studies were included in the qualitative synthesis. The pooled analysis revealed that PD was significantly associated with an increased risk of lung cancer (RR 1.71; 95%CI 1.61-1.81; P < 0.01). Subgroup analysis was performed based on gender distribution, geographic location, and type of studies.

Conclusion

From this current evidence, PD is a potential risk factor for the development of lung cancer. The risk for incidence of lung cancer is surged twice in the patients with PD, even though age and smoking are controlled in the studies.

Oral microbiota in oropharyngeal cancers: Friend or foe?

Oral microbiome is a complex population of micro-organisms, which by cross-talking with the local immune system, plays a major role in the immune homeostasis of the oral cavity, further contributing in the physiology of the gastro-intestinal microbiota. Understanding their involvement in the onset and pathogenesis of oropharyngeal cancers is paramount, despite very few reports deal with the fundamental role exerted by oral microbiota disorders, such as dysbiosis and impairment in the oral microbiome composition as causative factors in the development of oropharyngeal tumors. Current research, via metabolomic or meta-transcriptomic analyses, is wondering how this complex microbial population regulates the immune homeostasis in oral and pharyngeal mucosa and whether changes in bacterial composition may give insights on the role of oral microbiome in the development of oropharyngeal tumors, so to prevent their occurrence.

Low level of antibodies to the oral bacterium Tannerella forsythia predicts bladder cancers and Treponema denticola predicts colon and bladder cancers: A prospective cohort study

This study explores the risk for cancer by level of antibodies to the anaerobe oral bacteria of periodontitis Tannerella forsythia (TF), Porphyromonas gingivalis (PG), and Treponema denticola (TD) all three collectively termed the red complex, and the facultative anaerobe bacterium Aggregatibacter actinomycetemcomitans (AA). The prospective cohort, the Oslo II-study from 2000, the second screening of the Oslo study of 1972/73, has been followed for 17 ½ years with regard to cancer incidence and mortality. A random sample of 697 elderly men comprised the study cohort. The antibody results measured by enzyme linked immunosorbent assay (ELISA) were used in the Cox proportional hazards analyses, and quartile risk on cancer incidence in a 17 ½ years follow-up. Among the 621 participants with no prior cancer diagnoses, 221 men developed cancer. The incidence trend was inverse, and the results are shown as 1^st quartile of highest value and 4^th as lowest of antibody levels. The results of the Cox proportional regression analyses showed that TF inversely predicts bladder cancer (n = 22) by Hazard Ratio (HR) = 1.71 (95% CI: 1.12, 2.61). TD inversely predicts colon cancer (n = 26) by HR = 1.52 (95% CI: 1.06, 2.19) and bladder cancer (n = 22) by HR = 1.60 (95% CI: 1.05, 2.43). Antibodies to two oral bacteria, TF and TD, showed an inverse risk relationship with incidence of specific cancers: TF bladder cancer, TD bladder and colon cancer. Lowered immunological response to the oral infection, periodontitis, is shown to be a risk factor in terms of cancer aetiology.

Presence of periodontitis may synergistically contribute to cancer progression via Treg and IL-6

A close causal relationship has been suggested to exist between cancer and periodontitis. We hypothesized that the immune surveillance system is impaired in patients with periodontitis, which contributes to cancer development and growth. Therefore, the present study investigated the relationship between immune surveillance mechanisms and periodontitis in cancer patients. The presence or absence of periodontitis was assessed and the peripheral blood (PB) concentrations of IL-6, immunosuppressive cytokines (VEGF, TGF-β1, and CCL22) and proportion of T regulatory cells (Treg, CD3 + CD4 + CD25 + Foxp3 +) were measured. Subjects were classified into the following four groups: non-cancer patients without periodontitis (C − P −), non-cancer patients with periodontitis (C − P +), cancer patients without periodontitis (C + P −), and cancer patients with periodontitis (C + P +). The results of a multivariate analysis showed that the PB concentration of IL-6 was significantly higher in C + than in C- and higher in C + P + than in C + P −. The PB proportion of Treg was significantly higher in C + P + than in C + P −, C − P + , and C − P −. The results of this study suggested that the presence of periodontitis and cancer synergistically increased Treg in PB, which may be one of the underlying causes of immunosuppression and immune evasion in cancer. It was also suggested that the presence of periodontal disease and/or cancer also increases IL-6 in PB, which would be associated with cancer progression. These results suggest the possibility that the presence of periodontitis might synergistically contribute to cancer progression.

Periodontal Pathogens: A Crucial Link Between Periodontal Diseases and Oral Cancer

Emerging evidence shows a striking link between periodontal diseases and various human cancers including oral cancer. And periodontal pathogens, leading to periodontal diseases development, may serve a crucial role in oral cancer. This review elucidated the molecular mechanisms of periodontal pathogens in oral cancer. The pathogens directly engage in their own unique molecular dialogue with the host epithelium to acquire cancer phenotypes, and indirectly induce a proinflammatory environment and carcinogenic substance in favor of cancer development. And functional, rather than compositional, properties of oral microbial community correlated with cancer development are discussed. The effect of periodontal pathogens on periodontal diseases and oral cancer will further detail the pathogenesis of oral cancer and intensify the need of maintaining oral hygiene for the prevention of oral diseases including oral cancer.

It Takes Two to Tango: A Review of Oncogenic Virus and Host Microbiome Associated Inflammation in Head and Neck Cancer

Simple Summary

Certain viruses, specifically, human papillomavirus (HPV) and Epstein–Barr virus (EBV), have been linked with the development of head and neck cancer. In this study, we review the mechanisms by which (these) viruses lead to cellular transformation and a chronic inflammatory state. Given that the head and neck host a rich microbiome (which itself is intrinsically linked to inflammation), we scrutinize the literature to highlight the interplay between viruses, cellular transformation, inflammation, and the local host microbiome in head and neck cancer.

Abstract

While the two primary risk factors for head and neck squamous cell carcinoma (HNSCC) are alcohol and tobacco, viruses account for an important and significant upward trend in HNSCC incidence. Human papillomavirus (HPV) is the causative agent for a subset of oropharyngeal squamous cell carcinoma (OPSCC)—a cancer that is impacting a rapidly growing group of typically middle-aged non-smoking white males. While HPV is a ubiquitously present (with about 1% of the population having high-risk oral HPV infection at any one time), less than 1% of those infected with high-risk strains develop OPSCC—suggesting that additional cofactors or coinfections may be required. Epstein–Barr virus (EBV) is a similarly ubiquitous virus that is strongly linked to nasopharyngeal carcinoma (NPC). Both of these viruses cause cellular transformation and chronic inflammation. While dysbiosis of the human microbiome has been associated with similar chronic inflammation and the pathogenesis of mucosal diseases (including OPSCC and NPC), a significant knowledge gap remains in understanding the role of bacterial-viral interactions in the initiation, development, and progression of head and neck cancers. In this review, we utilize the known associations of HPV with OPSCC and EBV with NPC to investigate these interactions. We thoroughly review the literature and highlight how perturbations of the pharyngeal microbiome may impact host-microbiome-tumor-viral interactions—leading to tumor growth.

The Crossroads of Periodontitis and Oral Squamous Cell Carcinoma: Immune Implications and Tumor Promoting Capacities

Periodontitis (PD) is increasingly considered to interact with and promote a number of inflammatory diseases, including cancer. In the case of oral squamous cell carcinoma (OSCC) the local inflammatory response associated with PD is capable of triggering altered cellular events that can promote cancer cell invasion and proliferation of existing primary oral carcinomas as well as supporting the seeding of metastatic tumor cells into the gingival tissue giving rise to secondary tumors. Both the immune and stromal components of the periodontium exhibit phenotypic alterations and functional differences during PD that result in a microenvironment that favors cancer progression. The inflammatory milieu in PD is ideal for cancer cell seeding, migration, proliferation and immune escape. Understanding the interactions governing this attenuated anti-tumor immune response is vital to unveil unexplored preventive or therapeutic possibilities. Here we review the many commonalities between the oral-inflammatory microenvironment in PD and oral-inflammatory responses that are associated with OSCC progression, and how these conditions can act to promote and sustain the hallmarks of cancer.

Periodontitis, Helicobacter pylori infection, and gastrointestinal tract cancer mortality

AIM

Periodontitis has been proposed to lead to Helicobacter pylori infection, which could cause many gastrointestinal tract cancers. This study aimed to determine the association or otherwise between periodontitis and survival outcomes in individuals with respect to H. pylori infection.

MATERIALS AND METHODS

The study population comprised 4955 subjects aged 20-90 who had received both periodontal examination and H. pylori serum test in the Third National Health and Nutrition Examination Survey (NHANES III) database. Logistic regression models were used to analyse the association between periodontitis and H. pylori seropositivity (H. pylori infection). Survival analysis was performed using the NHANES III linked to mortality data. Cox proportional hazard regression was carried out to investigate the association between periodontitis and gastrointestinal tract cancer mortality in individuals with/without H. pylori infection.

RESULTS

Compared to periodontal health, periodontitis was significantly associated with increased odds of H. pylori infection (OR = 1.271, 95% CI = 1.177-1.372). Periodontitis significantly increased the mortality risk from all causes (HR = 1.574, 95% CI = 1.327-1.866) and all cancers (HR = 1.948, 95% CI = 1.701-2.232), including gastrointestinal (GI) tract cancer (HR = 4.140, 95% CI = 3.656-4.687), gastric cancer (HR = 4.288, 95% CI = 3.969-4.632), and colorectal cancer (HR = 4.814, 95% CI = 3.849-6.020) in subjects with H. pylori infection after adjusting for health-related factors. Periodontitis was significantly related to the decreased survival time in subjects with GI tract (p = .001) or colorectal cancer (p = .002) and H. pylori infection.

CONCLUSION

Our study demonstrated that periodontitis was significantly associated with higher mortality risk of GI tract, gastric, and colorectal cancer in subjects with H. pylori infection. Owing to an interactive effect between periodontitis and H. pylori infection on cancer mortality, H. pylori infection has a significant moderating effect in regulating the association between periodontitis and mortality due to all cancers, including GI tract cancer and colorectal cancer.

Bacterial and Parasitic Pathogens as Risk Factors for Cancers in the Gastrointestinal Tract: A Review of Current Epidemiological Knowledge

The oncogenic potential of viral infections is well established and documented for many years already. However, the contribution of (commensal) bacteria and parasites to the development and progression of cancers has only recently gained momentum, resulting in a rapid growth of publications on the topic. Indeed, various bacteria and parasites have been suggested to play a role in the development of gastrointestinal cancer in particular. Therefore, an overview of the current epidemiological knowledge on the association between infections with bacteria and parasites and cancers of the gastrointestinal tract is needed. In this review, we summarized the methodological characteristics and main results of epidemiological studies investigating the association of 10 different bacteria (Bacteroides fragilis, Campylobacter spp., Clostridium spp., Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Porphyromonas gingivalis, non-typhoidal Salmonella, Salmonella Typhi, and Streptococcus spp.) and three parasites (Cryptosporidium spp., Schistosoma spp., and Strongyloides stercoralis) with gastrointestinal cancer. While the large body of studies based on microbiome sequencing provides valuable insights into the relative abundance of different bacterial taxa in cancer patients as compared to individuals with pre-malignant conditions or healthy controls, more research is needed to fulfill Koch's postulates, possibly making use of follow-up data, to assess the complex role of bacterial and parasitic infections in cancer epidemiology. Studies incorporating follow-up time between detection of the bacterium or parasite and cancer diagnosis remain valuable as these allow for estimation of cause-effect relationships.

Periodontal Inflammation and Systemic Diseases: An Overview

Periodontitis is a common inflammatory disease of infectious origins that often evolves into a chronic condition. Aside from its importance as a stomatologic ailment, chronic periodontitis has gained relevance since it has been shown that it can develop into a systemic condition characterized by unresolved hyper-inflammation, disruption of the innate and adaptive immune system, dysbiosis of the oral, gut and other location's microbiota and other system-wide alterations that may cause, coexist or aggravate other health issues associated to elevated morbi-mortality. The relationships between the infectious, immune, inflammatory, and systemic features of periodontitis and its many related diseases are far from being fully understood and are indeed still debated. However, to date, a large body of evidence on the different biological, clinical, and policy-enabling sources of information, is available. The aim of the present work is to summarize many of these sources of information and contextualize them under a systemic inflammation framework that may set the basis to an integral vision, useful for basic, clinical, and therapeutic goals.

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.

Oral cancer in non-smoker non-drinker patients. Could comparative pet oncology help to understand risk factors and pathogenesis?

During the last decades there has been a progressive increase in proportion of incidence of oral cancer not related to a known etiologic factor, such as the so-called "oral cancer in young", a relevant tumor in non-smoker non-drinker (NSND) patients. The topic is matter of long standing debate, and adequate study models to analyze this entity are lacking. Spontaneous oral cancer in companion animals such as dogs and cats, presents more clinical and biological similarities with the human oral cancer than any other animal model. In our review we analyze how the study of spontaneous oral cancer in common pets can prospectively prove to be of double usefulness in unraveling the question about the origin of oral cancer in NSND patients, allowing both the analysis of environmental and behavioral risk factors, and the study of how carcinogenic viruses, chronic inflammation, and changes in immunity can influence pre-tumoral and tumoral microenvironment.

Dental Care Use, Edentulism, and Systemic Health among Older Adults

Past research suggests there are systematic associations between oral health and chronic illness among older adults. Although causality has not yet been credibly established, periodontitis has been found to be associated with higher risk of both heart disease and stroke. We advance this literature by estimating the direct association between dental care use and systemic health using multiple waves of the 1992 to 2016 Health and Retirement Study. Through the inclusion of individual fixed effects in our regression models, we account for unobservable time-invariant characteristics of individuals that might otherwise bias estimates of the association between dental care use and health. We find statistically significant negative associations between dental care use and the number of health conditions, self-reported overall health, the incidence of heart disease, and the incidence of stroke. In particular, the use of dental care within the past 2 y is associated with a 2.7% reduction in the likelihood of being diagnosed with a heart condition and a reduction in the likelihood of a stroke diagnosis of between 5.3% and 11.6%. We also find large positive correlations between edentulism and the measures of chronic illness. Associations from models estimated separately for men and women are qualitatively similar to one another. These findings provide additional motivation for the consideration of a Medicare dental benefit.

Two-Sample Mendelian Randomization Analysis of Associations Between Periodontal Disease and Risk of Cancer

Background

Observational studies indicate that periodontal disease may increase the risk of colorectal, lung, and pancreatic cancers. Using a 2-sample Mendelian randomization (MR) analysis, we assessed whether a genetic predisposition index for periodontal disease was associated with colorectal, lung, or pancreatic cancer risks.

Methods

Our primary instrument included single nucleotide polymorphisms with strong genome-wide association study evidence for associations with chronic, aggressive, and/or severe periodontal disease (rs729876, rs1537415, rs2738058, rs12461706, rs16870060, rs2521634, rs3826782, and rs7762544). We used summary-level genetic data for colorectal cancer (n = 58 131 cases; Genetics and Epidemiology of Colorectal Cancer Consortium, Colon Cancer Family Registry, and Colorectal Transdisciplinary Study), lung cancer (n = 18 082 cases; International Lung Cancer Consortium), and pancreatic cancer (n = 9254 cases; Pancreatic Cancer Consortia). Four MR approaches were employed for this analysis: random-effects inverse-variance weighted (primary analyses), Mendelian Randomization-Pleiotropy RESidual Sum and Outlier, simple median, and weighted median. We conducted secondary analyses to determine if associations varied by cancer subtype (colorectal cancer location, lung cancer histology), sex (colorectal and pancreatic cancers), or smoking history (lung and pancreatic cancer). All statistical tests were 2-sided.

Results

The genetic predisposition index for chronic or aggressive periodontitis was statistically significantly associated with a 3% increased risk of colorectal cancer (per unit increase in genetic index of periodontal disease; P = .03), 3% increased risk of colon cancer (P = .02), 4% increased risk of proximal colon cancer (P = .01), and 3% increased risk of colorectal cancer among females (P = .04); however, it was not statistically significantly associated with the risk of lung cancer or pancreatic cancer, overall or within most subgroups.

Conclusions

Genetic predisposition to periodontitis may be associated with colorectal cancer risk. Further research should determine whether increased periodontitis prevention and increased cancer surveillance of patients with periodontitis is warranted.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Preoperative C-reactive protein to albumin ratio and oral health in oral squamous cell carcinoma patients

Background

The C-reactive protein to albumin (CRP/alb) ratio can predict early survival of a hospitalized patient. We evaluated factors that influence the preoperative CRP/alb ratio in oral squamous cell carcinoma (OSCC) patients and in particular clarified the role of oral health to this ratio.

Materials and methods

Data from surgically treated OSCC patients were collected retrospectively. The outcome variables were preoperative CRP/alb ratio, CRP level, and alb level. The studied predictors were total number of teeth, periodontal stability, marginal bone loss, tumour stage, T-class, lymph node status, and site. The statistical significance of age, sex, comorbidity combination of age and disease history (Charlson Comorbidity Index [CCI]), smoking, and alcohol history for outcome variables were evaluated. Patient 3-month mortality and occurrence of postoperative infections were recorded.

Results

A total of 159 patients were included in the study. The early mortality was 3.8%. CRP/alb was higher in these patients than in those who survived. The only independent variables for CRP/alb changes were CCI and heavy alcohol use. The CRP/alb ratio was significantly lower in non-heavy alcohol users (odds ratio [OR] 0.114, 95% confidence interval [CI] 0.024–0.541; adjusted p = 0.006) than in other patients. Patients with CCI 0–1 were more likely to have a lower CRP/alb ratio than patients with CCI ≥ 5 (OR 0.033, 95% CI 0.004–0.284; adjusted p = 0.002). In addition, high CRP/alb ratio associated with postoperative infections (p = 0.026).

Conclusions

The CRP/alb ratio was high in OSCC patients with combined comorbities of age and disease history and in patients with heavy alcohol use. Oral health or tumour-related variables did not independently affect the CRP/alb ratio. The CRP/alb ratio appears suitable for prediction of OSCC patient early survival.

Periodontal disease and the risk of prostate cancer: a meta-analysis of cohort studies

Background:

Periodontal disease is reportedly associated with the risk of various systemic diseases, including pancreatic and lung cancers. However, its association with prostate cancer remains inconclusive. Herein, we explored the association of periodontal disease with the risk of prostate cancer through a meta-analysis.

Materials and Methods:

MEDLINE, Embase, Web of Sciences and Cochrane Library databases were searched for eligible publications up to April 2020. Multivariate adjusted risk estimates with corresponding 95% confidence intervals (CIs) were extracted and calculated using random- or fixed-effect models.

Results:

Nine cohort studies involving 3.353 prostate cancer cases with 440.911 participants were identified and included in the meta-analysis. We found that periodontal disease significantly increased the risk of prostate cancer by 1.40-fold (hazard ratio [HR]=1.40, 95% CI: 1.16-1.70; P=0.001; I2=76.1%) compared with normal condition. Interestingly, the risk of developing prostate cancer was not significant in patients treated with periodontal therapy (HR=1.22, 95% CI: 0.86-1.73; P=0.272; I2=65.2%). The results of subgroup analyses were also consistent and significant when stratified by study design and follow-up period, whereas conflicting results were observed in periodontal disease ascertainment stratification. These findings were robust as indicated by sensitivity analyses.

Conclusions:

Periodontal disease was associated with the increased risk of prostate cancer, whereas no significant association was observed in patients treated with periodontal therapy. Hence, the awareness and importance for maintaining oral health should be improved, and the underlying mechanisms linking periodontal disease and prostate cancer should be fully explored in future research.

Association of periodontitis and tooth loss with liver cancer: A systematic review

A number of epidemiological studies have suggested a positive association between periodontal diseases and oro-digestive cancers, including liver cancer. The purpose of the present systematic review was to analyze the current evidence regarding the potential association between periodontitis and/or tooth loss and the risk of liver cancer. A comprehensive search of PubMed, Scopus and Web of Science databases was conducted in August 2019. The inclusion criteria comprised all observational studies that assessed the relationship between periodontitis or tooth loss and liver cancer. Case reports, animal studies, experimental studies, and reviews were excluded. Due to great heterogeneity among the included studies, no meta-analysis was conducted. Six studies (five prospective cohorts and one case-control) comprising 619,834 subjects (including 916 liver cancer cases) were included. The studies were conducted in the United States, Europe, and Asia. Three large-scale cohort studies reported a positive association between periodontitis or tooth loss and the risk of liver cancer. One case-control study found some association between liver cancer and loss of 12-23 teeth, but such association was not replicated in patients with greater number of tooth loss. Contrarily, two studies failed to report any association between periodontitis and/or tooth loss and the risk of liver cancer. The available evidence suggests a possible link between tooth loss/periodontitis and the risk of liver cancer. However, the evidence is not conclusive enough, a fact that drives to conduct more, well-designed, prospective cohort studies to further explore the potential association between periodontitis and the risk of liver cancer.

Nutrition as a Key Modifiable Factor for Periodontitis and Main Chronic Diseases

Nutrition is recognized as an essential component in the prevention of a number of chronic diseases, including periodontal disease. Based on these considerations, a better understanding is required regarding how the diet, and more particularly the intake of macronutrients and micronutrients, could impact the potential relationship between nutrition and periodontal diseases, periodontal diseases and chronic diseases, nutrition and chronic diseases. To overcome this complexity, an up-to-date literature review on the nutriments related to periodontal and chronic diseases was performed. High-sugar, high-saturated fat, low-polyols, low-fiber and low-polyunsaturated-fat intake causes an increased risk of periodontal diseases. This pattern of nutrients is classically found in the Western diet, which is considered as an ‘unhealthy’ diet that causes cardiovascular diseases, diabetes and cancers. Conversely, low-sugar, high-fiber and high-omega-6-to-omega-3 fatty acid ratio intake reduces the risk of periodontal diseases. The Mediterranean, DASH, vegetarian and Okinawa diets that correspond to these nutritional intakes are considered as ‘healthy’ diets, reducing this risk of cardiovascular diseases, diabetes and cancers. The role of micronutrients, such as vitamin D, E, K and magnesium, remains unclear, while others, such as vitamin A, B, C, calcium, zinc and polyphenols have been shown to prevent PDs. Some evidence suggests that probiotics and prebiotics could promote periodontal health. Periodontal and chronic diseases share, with a time delay, nutrition as a risk factor. Thus, any change in periodontal health should be considered as a warning signal to control the dietary quality of patients and thus reduce the risk of developing chronic diseases later on.

Effect of Periodontitis and Scaling and Root Planing on Risk of Pharyngeal Cancer: A Nested Case-Control Study

This study investigated the association between periodontitis and the risk of pharyngeal cancer in Taiwan. For this population-based nested case–control study using the Longitudinal Health Insurance Database derived from Taiwan’s National Health Insurance Research Database, we identified patients (n = 1292) who were newly diagnosed with pharyngeal cancer between 2005 and 2013 and exactly paired them with propensity score matched control subjects (n = 2584). Periodontitis and scaling and root planing (SRP) were identified before the index date. Pharyngeal cancer was subdivided into 3 subgroups on the basis of anatomic location: nasopharyngeal cancer, oropharyngeal cancer, and hypopharyngeal cancer. A multiple conditional logistic regression model was applied to analyze the adjusted odds ratio (aOR). Periodontitis was associated with an increased risk of pharyngeal cancer (aOR, 1.57; 95% confidence interval (CI), 1.17 to 2.10), especially oropharyngeal cancer (aOR, 2.22; 95% CI, 1.07 to 4.60). We found a decreased risk of pharyngeal cancer in patients who had undergone SRP (aOR, 0.77; 95% CI, 0.61 to 0.96). In conclusion, this study showed that periodontitis was associated with an increased risk of pharyngeal cancer and SRP exerted a protective effect against pharyngeal cancer. Our results suggest that treating periodontitis and performing SRP, which are modifiable factors in oral health, in clinical practice may provide an opportunity to decrease the disease burden of pharyngeal cancer in Taiwan.

Oral Microbiota and Cancer Development

Oral microbiota are among the most diverse in the human body. More than 700 species have been identified in the mouth, and new sequencing methods are allowing us to discover even more species. The anatomy of the oral cavity is different from that of other body sites. The oral cavity has mucosal surfaces (the tongue, the buccal mucosa, the gingiva, and the palate), hard tissues (the teeth), and exocrine gland tissue (major and minor salivary glands), all of which present unique features for microbiota composition. The connection between oral microbiota and diseases of the human body has been under intensive research in the past years. Furthermore, oral microbiota have been associated with cancer development. Patients suffering from periodontitis, a common advanced gingival disease caused by bacterial dysbiosis, have a 2-5 times higher risk of acquiring any cancer compared to healthy individuals. Some oral taxa, especially Porphyromonas gingivalis and Fusobacterium nucleatum, have been shown to have carcinogenic potential by several different mechanisms. They can inhibit apoptosis, activate cell proliferation, promote cellular invasion, induce chronic inflammation, and directly produce carcinogens. These microbiota changes can already be seen with potentially malignant lesions of the oral cavity. The causal relationship between microbiota and cancer is complex. It is difficult to accurately study the impact of specific bacteria on carcinoma development in humans. This review focuses on the elucidating the interactions between oral cavity bacterial microbiota and cancer. We gather literature on the current knowledge of the bacterial contribution to cancer development and the mechanisms behind it.

The Oral Microbiome and Cancer

There is mounting evidence that members of the human microbiome are highly associated with a wide variety of cancer types. Among oral cancers, oral squamous cell carcinoma (OSCC) is the most prevalent and most commonly studied, and it is the most common malignancy of the head and neck worldwide. However, there is a void regarding the role that the oral microbiome may play in OSCC. Previous studies have not consistently found a characteristic oral microbiome composition associated with OSCC. Although a direct causality has not been proven, individual members of the oral microbiome are capable of promoting various tumorigenic functions related to cancer development. Two prominent oral pathogens, Porphyromonas gingivalis, and Fusobacterium nucleatum can promote tumor progression in mice. P. gingivalis infection has been associated with oro-digestive cancer, increased oral cancer invasion, and proliferation of oral cancer stem cells. The microbiome can influence the evolution of the disease by directly interacting with the human body and significantly altering the response and toxicity to various forms of cancer therapy. Recent studies have shown an association of certain phylogenetic groups with the immunotherapy treatment outcomes of certain tumors. On the other side of the coin, recently it has been a resurgence in interest on the potential use of bacteria to cure cancer. These kinds of treatments were used in the late nineteenth and early twentieth centuries as the first line of defense against cancer in some hospitals but later displaced by other types of treatments such as radiotherapy. Currently, organisms such as Salmonella typhimurium and Clostridium spp. have been used for targeted strategies as potential vectors to treat cancer. In this review, we briefly summarize our current knowledge of the role of the oral microbiome, focusing on its bacterial fraction, in cancer in general and in OSCC more precisely, and a brief description of the potential use of bacteria to target tumors.

A systematic review and meta-analysis of the association between periodontitis and oral high-risk human papillomavirus infection

BACKGROUND

The incidence of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinomas (OPSCCs) is increasing globally. Common oral conditions such as periodontitis may contribute. We undertook a meta-analysis to quantify the association between periodontitis, oral HPV and OPSCCs.

METHODS

Multiple electronic databases were searched until 12 February 2020. Studies conducted in males and/or females aged ≥ 18 years that examined periodontitis, periodontal procedures, oral HPV infection, and where possible, oral cancers, were eligible. Meta-analyses were conducted and the GRADE approach was used to examine the quality of evidence.

RESULTS

Of 2709 studies identified, 13 met the eligibility criteria. Five studies could be included in the meta-analyses. There was no significant increase in the odds of high-risk oral HPV infection among individuals with confirmed periodontitis (odds ratio 4.71, 95% confidence interval 0.57-38.97). Individuals with periodontitis had a 3.65 times higher odds of having any type of oral HPV infection compared with those without periodontitis (95% confidence interval 1.67-8.01). The overall body of evidence was rated as low to very-low certainty.

CONCLUSION

Meta-analysis confirms there is a positive association between periodontitis and oral HPV infection, although the overall quality of this evidence is low. Evidence for an association between periodontitis and high-risk oral HPV infection is inconclusive.

Association of chronic periodontitis with prostatic hyperplasia and prostatitis: A population-based cohort study in Taiwan

BACKGROUND

Association between periodontitis and prostate diseases of benign prostatic hyperplasia (BPH) and prostatitis is uncertain.

METHODS

From the National Health Insurance Research Database of Taiwan, 5,510 patients with newly diagnosed chronic periodontitis and participated in therapies were selected from 2000 to 2015 as cohort 1. Matched with age and index year, 5,510 patients with periodontitis diagnosis without therapy were selected as cohort 2, and 5,510 participants without diagnosis were used as control. Cox proportional hazard and survival analysis were performed to compare the risks and the survival probabilities among cohorts.

RESULTS

In two periodontitis cohorts, 636 and 638 participants compared with 550 in control (1,174 and 1,187 versus 989 per 100,000 person-years) had prostate disorder. Difference was identified for prostatitis (n = 68, 70 versus 34; rate = 125, 130 versus 61 /100,000 person-years; P <0.001) but not for BPH (n = 577, 575, versus 529; rate = 1,065, 1,070 versus 951 /100,000 person-years, respectively). Different survival probabilities for prostate disorder and prostatitis, but not for BPH, were observed among cohorts. Periodontitis patients were more likely to develop prostate disorder after adjustment (adjusted hazard ratio [aHR] of 2.590 to 2.641 by competing model). With stratification, risks between two periodontitis cohorts exhibited no difference. When BPH cases were excluded, the aHRs for prostatitis were 4.611 to 4.798.

CONCLUSIONS

Despite treatment, the patients with periodontitis had higher risk of developing prostatitis than patients without periodontitis.

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.

Breast cancer colonization by Fusobacterium nucleatum accelerates tumor growth and metastatic progression

Fusobacterium nucleatum is an oral anaerobe recently found to be prevalent in human colorectal cancer (CRC) where it is associated with poor treatment outcome. In mice, hematogenous F. nucleatum can colonize CRC tissue using its lectin Fap2, which attaches to tumor-displayed Gal-GalNAc. Here, we show that Gal-GalNAc levels increase as human breast cancer progresses, and that occurrence of F. nucleatum gDNA in breast cancer samples correlates with high Gal-GalNAc levels. We demonstrate Fap2-dependent binding of the bacterium to breast cancer samples, which is inhibited by GalNAc. Intravascularly inoculated Fap2-expressing F. nucleatum ATCC 23726 specifically colonize mice mammary tumors, whereas Fap2-deficient bacteria are impaired in tumor colonization. Inoculation with F. nucleatum suppresses accumulation of tumor infiltrating T cells and promotes tumor growth and metastatic progression, the latter two of which can be counteracted by antibiotic treatment. Thus, targeting F. nucleatum or Fap2 might be beneficial during treatment of breast cancer.

High levels of Fusobacterium nucleatum have been associated with poor overall survival in patients with colorectal and esophageal cancer. Here, the authors show that F. nucleatum is abundant in breast cancer samples and that the colonization by F. nucleatum accelerates tumor growth and metastasis in preclinical breast cancer models.

Periodontitis in tonsil cancer patients-A comparative study in accordance with tumour p16 status

OBJECTIVES

We assessed the periodontal situation radiologically according to tumour p16 status.

MATERIALS AND METHODS

Patients with a diagnosis of tonsillar cancer and availability of a digital panoramic radiograph (DPR) during a 5-year period were included in this retrospective study. The predictor variables were periodontal stability, marginal bone loss, marginal bone loss without periodontal stability and total number of teeth. Periodontal status was compared with p16 status, age, gender, smoking and alcohol use.

RESULTS

Among 115 patients included in the analyses (p16-negative, n = 24; p16-positive, n = 91), smoking (p < .0001), heavy alcohol use (p < .0001) and total number of teeth (p = .0001) were significantly associated with p16 status. Current smoking (OR = 7.3) and heavy alcohol use (OR = 10.1) increased the risk of p16-negative cancer.

CONCLUSIONS

Patients with p16-negative tonsillar carcinoma had less teeth than patients with p16-positive tumours. Other periodontal findings were common in both groups without statistical significance. Heavy alcohol use and smoking were the most important risk factors for p16-negative tonsillar carcinoma.