Oral health and risk of colorectal cancer: results from three cohort studies and a meta-analysis

Oral dysbiosis and risk of gastrointestinal cancers: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

Poor oral health and oral dysbiosis were found to be associated with cancers, especially of the gastrointestinal (GI) system. But the cause-and-effect relationship and the effect of the risk are not yet known due to scarcity of literature. Understanding such risk relationship can contribute to an integrated multi-disciplinary approach for GI cancer prevention.

AIM

The aim of the present systematic review and meta-analysis is to assess the role of oral dysbiosis on increasing the risk of digestive system cancers.

OBJECTIVE

To evaluate the effect of poor oral health on increasing the risk of gastrointestinal cancers.

METHODS

We conducted a systematic search following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in databases PubMed, Elsevier, Wiley's online library and Web of Science from inception to February 2023 to include recent cohort studies that assessed the association between poor oral health and the risk of cancer. We assessed bias using the New Castle Ottawa scale. We used inferential statistics to describe the effect of oral dysbiosis on gastrointestinal cancers. We performed a sub-group analysis to assess the effect of oral conditions on individual cancers.

RESULTS

We included 10 longitudinal studies in the meta-analysis. The overall effect size of poor oral health and GI cancer risk was hazard's ratio (HR) =1.30 (95% CI: [1.14, 1.46]) (p<0.001) (I2 = 68.78). Sub-group analysis indicated that poor oral health increases the risk of esophageal cancer HR=1.61 (95% CI: [1.37, 1.85]), stomach cancer HR=1.33 (95% CI: [1.08, 1.58]), pancreatic cancer HR=1.90 (95% CI; [1.29, 2.50]) and colorectal and hepatocellular carcinoma HR=1.16 (95% CI: [1.08, 1.23]).

CONCLUSION

The meta-analysis indicated that poor oral health was significantly associated with increasing the risk of GI cancers.

The Oral Microbiome as Mediator between Oral Hygiene and Its Impact on Nasopharyngeal Carcinoma

Oral hygiene and the alteration of the oral microbiome have been linked to nasopharyngeal carcinoma (NPC). This study aimed to investigate whether the oral microbiome plays a mediating role in the relationship between oral hygiene and NPC, and identify differential microbial taxonomies that potentially mediated this association. We conducted a case–control study that involved 218 NPC patients and 192 healthy controls. The 16S rRNA gene sequencing of the V4 region was performed to evaluate the composition of the oral microbiome. Mediation analysis was applied to explore the relationship among oral hygiene, the oral microbiome and NPC. We found that dental fillings and poor oral hygiene score were associated with increased risks of NPC (OR = 2.51 (1.52–4.25) and OR = 1.54 (1.02–2.33)). Mediation analysis indicated that dental fillings increased the risk of NPC by altering the abundance of Erysipelotrichales, Erysipelotrichaceae, Solobacterium and Leptotrichia wadei. In addition, Leptotrichia wadei also mediated the association between oral hygiene score and the risk of NPC. Our study confirmed that poor oral hygiene increased the risk of NPC, which was partly mediated by the oral microbiome. These findings might help us to understand the potential mechanism of oral hygiene influencing the risk of NPC via the microbiome.

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.

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.

Tooth Loss and Risk of Lung Cancer among Urban Chinese Adults: A Cohort Study with Meta-Analysis

Epidemiological evidence on tooth loss and lung cancer risk remains limited, especially for smoking-specific associations. To investigate the association between tooth loss and lung cancer risk by smoking status, we first analyzed data from the Shanghai Men’s Health Study (n = 49,868) and the Shanghai Women’s Health Study (n = 44,309). Cox regression models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer risk in relation to tooth loss. We also conducted a meta-analysis to summarize epidemiologic findings to date, incorporating results from the current study and six previously published studies. For 7.3 median follow-up years, 973 incident lung cancer cases (613 men and 360 women) were ascertained. After adjustment for major covariates, tooth loss was associated with an increased risk of lung cancer among men (HR [95% CI] for >10 teeth vs. none = 1.59 [1.21−2.11]) but not among women (0.86 [0.50−1.46]). The positive association was stronger among male current smokers (1.75 [1.26−2.45], p-interaction by smoking status = 0.04). In a meta-analysis incorporating 4052 lung cancer cases and 248,126 non-cases, tooth loss was associated with a 1.64-fold increased risk of developing lung cancer (relative risk [RR, 95% CI] for the uppermost with the lowest category = 1.64 [1.44−1.86]). The positive association was more evident among current smokers (1.86 [1.41−2.46]), but no significant associations were found among never or former smokers. Our findings suggest that tooth loss may be associated with an increased risk of lung cancer, and the association could be modified by smoking status.

A Noninvasive Risk Stratification Tool Build Using an Artificial Intelligence Approach for Colorectal Polyps Based on Annual Checkup Data

Colorectal cancer is the leading cause of cancer-related deaths worldwide, and early detection has proven to be an effective method for reducing mortality. The machine learning method can be implemented to build a noninvasive stratifying tool that helps identify patients with potential colorectal precancerous lesions (polyps). This study aimed to develop a noninvasive risk-stratified tool for colorectal polyps in asymptomatic, healthy participants. A total of 20,129 consecutive asymptomatic patients who underwent a health checkup between January 2005 and August 2007 were recruited. Positive relationships between noninvasive risk factors, such as age, Helicobacter pylori infection, hypertension, gallbladder polyps/stone, and BMI and colorectal polyps were observed (p < 0.0001), regardless of sex, whereas significant findings were noted in men with tooth disease (p = 0.0053). A risk stratification tool was developed, for colorectal polyps, that considers annual checkup results from noninvasive examinations. For the noninvasive stratified tool, the area under the receiver operating characteristic curve (AUC) of obese females (males) aged <50 years was 91% (83%). In elderly patients (>50 years old), the AUCs of the stratifying tools were >85%. Our results indicate that the risk stratification tool can be built by using random forest and serve as an efficient noninvasive tool to identify patients requiring colonoscopy.

Relationship between maximum occlusal force and gastrointestinal cancer in community-dwelling older Japanese adults

Globally, the cancer burden is expected to increase as populations are ageing. Therefore, cancer prevention among older age groups is important. This prospective cohort study examined the relationship between the number of remaining teeth, maximum occlusal force, and incidence of gastrointestinal cancer in community-dwelling older Japanese individuals using data from the Tsurugaya project; 847 participants were included. The exposure variables were the number of remaining teeth and the maximum occlusal force, with the outcome being the incidence of gastrointestinal cancer. Covariates were age, sex, medical history, smoking, alcohol consumption, educational attainment, and physical function. The Cox proportional hazard model was used to examine the relationship between the number of remaining teeth, maximum occlusal force, and incidence of gastrointestinal cancer. With a median follow-up of 7.6 years, 63 participants were confirmed to have gastrointestinal cancer. The risk of gastrointestinal cancer was significantly higher in those with an occlusal force lower than the median (hazard ratio, 2.80; 95% confidence interval, 1.54–5.10). No significant risk difference was found according to the number of remaining teeth. Low maximum occlusal force was associated with the incidence of gastrointestinal cancer in community-dwelling older Japanese adults.

The differences between fecal microbiota and intestinal fluid microbiota in colon polyps: An observational study

Generally, intestinal microbiota can be classified into intestinal cavity microbiota and mucosal microbiota, among which, the former is the default type. This study aimed to identify the differences between fecal microbiota and intestinal fluid microbiota in colon polys.This study enrolled patients with colon polys who met the Rome-III criteria to carry out 16s rDNA gene sequencing. Then, both fresh feces as well as intestinal fluid was sampled. Thereafter, α/β diversities, together with the heterogeneities with regard to microbial function and structure were assessed among those intestinal fluid and fresh feces samples collected.According to bioinformatics analysis, difference in α-diversity was not statistically significant between intestinal fluid microbiota and fecal microbiota among patients with colorectal polyps (CPs). Non-metric multidimensional scaling analysis of β-diversity revealed that differences were of statistical significance between both groups. In addition, linear discriminant analysis effect size analysis displayed great heterogeneities in intestinal microbiota of both groups, including Firmicutes, Clostridia, and Phascolarctobacterium. At the phylum level, difference (P = .016) in Spirochaetes was statistically significant between the intestinal fluid group and fecal group. At the family level, differences in Bacteroidaceae, Micrococcaceae, F16, Spirocheatacae, Enterobacteriaceae, Cardiobacteriaceae, Turkish Spirobacteriaceae, Bifidobacteriaceae, and Dethiosulfovibrionaceae were statistically significant between the 2 groups. At the genus level, there were statistical differences between the 2 groups in terms of Bacteroidetes, Rothia, Actinobacillus, F16, Treponema, Oscillospira, Turicibacter, Sharpea, Heamophilus, Veillonella, and Cardiobacterium.There are statistical differences in the composition between intestinal microbiota and fecal microbiota in CP patients, both of which are equally important and indispensable for analyzing the intestinal microbiota in CP patients.

Oral health and gastrointestinal neoplasia: Narrative review

The oral cavity represents the gateway to the complex digestive system, so the knowledge of the exact mechanisms that link them is vitally important. Recently, oral and dental pathologies have been studied as potential risk factors for pathologies linked to lifestyle habits. Therefore, it could be considered as an interesting preventive way. We conducted a narrative review with a thorough bibliographic search on MEDLINE and SCOPUS, including international studies related to oral healthcare and gastrointestinal neoplasms, published between 2015 and 2020. The primary aim of this revision is to analyze the association between oral healthcare and carcinogenic gastrointestinal processes, providing a possible future preventive strategy for dental care. Moreover, we intend to raise awareness about the importance of oral healthcare as a new paradigm and study variable in the global health care system.

Associations between oral health and cancer in a national representative sample of Spanish adults

BACKGROUND

The goal of this study was to investigate the association between several oral health outcomes and cancer in adults living in Spain.

METHODS

Data from the Spanish National Health Survey 2017 were analysed. Seven oral health outcomes (dental caries, dental extraction, dental filling, gingival bleeding, tooth movement, dental material and missing tooth) were assessed with questions with 'yes' and 'no' options. Cancer was assessed and defined with the following yes-no question: 'Have you ever been diagnosed with malignant tumours?'. The relationship of each oral health outcome and the number of poor oral health outcomes with cancer was studied in regression models adjusted for sex, age, marital status, education, smoking and alcohol consumption.

RESULTS

This study included 23 089 participants aged 15-103 years [45.9% of males; mean (standard deviation) age 53.4 (18.9) years]. The prevalence of cancer was 5.0% in the overall population. After adjusting for several potential confounding factors, all oral health outcomes except missing tooth were significantly and positively associated with cancer [odds ratios (ORs) ranging from 1.15 for dental filling to 1.48 for dental extraction]. In addition, there was a positive and significant association between the number of poor oral health outcomes and cancer (OR = 1.16, 95% confidence interval = 1.11-1.22).

CONCLUSIONS

On a nationally representative sample of 23 089 participants in Spain, poorer oral health outcomes were found in participants with history of cancer, with positive associations between several oral health outcomes as well as the number of poor oral health outcomes and cancer.

Oral health and gastrointestinal neoplasia: Narrative review

The oral cavity represents the gateway to the complex digestive system, so the knowledge of the exact mechanisms that link them is vitally important. Recently, oral and dental pathologies have been studied as potential risk factors for pathologies linked to lifestyle habits. Therefore, it could be considered as an interesting preventive way. We conducted a narrative review with a thorough bibliographic search on MEDLINE and SCOPUS, including international studies related to oral healthcare and gastrointestinal neoplasms, published between 2015 and 2020. The primary aim of this revision is to analyze the association between oral healthcare and carcinogenic gastrointestinal processes, providing a possible future preventive strategy for dental care. Moreover, we intend to raise awareness about the importance of oral healthcare as a new paradigm and study variable in the global health care system.

A Likely Role for a Novel Cell Therapeutic Target of Transforming Growth Factor-β1 on Radiation Pneumonitis in Lung and Nasopharyngeal Cancer Patients

The association between the polymorphism of transforming growth factor (TGF)-β1 and risk of radiation pneumonitis has been extensively investigated; however, conclusive results were unavailable. Eligible studies were identified from the database of Medline, Web of Science, EMBASE, and CNKI (China Knowledge Resource Integrated Database) up to September 2019. The odds ratio (OR) and 95% confidence interval (95% CI) were used to assess the strength of the relationship. The results showed that there were associations between TGF 869 T/C (rs1982073) and risks of radiation pneumonitis. Subgroup analyses showed that TGF 869 T/C was associated with risk of radiation pneumonitis in Caucasians (OR [95% CI]: 0.45 [0.31 to 0.67] for C carriers vs. TT). In addition, subgroup analyses also suggested that the C allele was associated with decreased risks of radiation pneumonitis among hospital-based case–control studies (0.56 [0.39 to 0.82] for C carriers vs. TT). Meanwhile, C allele was also suggested to be associated with decreased risk of radiation pneumonitis among PCC (0.60 [0.38 to 0.96] for C carriers vs. TT). Especially, C allele was also found to be associated with decreased risk of radiation pneumonitis from the participants with lung cancer (0.57 [0.37 to 0.90] for C carriers vs. TT). Our meta-analysis shows that T allele in TGF 869 T/C is significantly associated with the increased risk of radiation pneumonitis, especially for Caucasians, and for the participants with lung cancer.

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.

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.

Is periodontal disease a risk indicator for colorectal cancer? A systematic review and meta-analysis

AIMS

Existing epidemiological studies have suggested that periodontal disease (PD) may be a risk indicator for colorectal cancer (CRC). However, no formal systematic review and meta-analysis have been performed. Therefore, we aimed to evaluate the association between PD and CRC risk in this study.

MATERIALS AND METHODS

We used the PubMed, EMBASE, Cochrane Library and Web of Science to search for related articles published from 1 January 1966 to 16 July 2020. Stata (Version 15) software was used to calculate the total risk ratio (RR) and 95% confidence interval (CI) of the included studies through the random-effects model to assess the association between PD and CRC risk.

RESULTS

Nine studies were included in the narrative synthesis, and seven studies were included in the meta-analysis. Results showed that PD significantly increased the risk of CRC by 44% (RR, 1.44; 95% CI, 1.18-1.76; I² , 55.2%).

CONCLUSION

We found an association between PD and CRC. PD can be a potential risk indicator for the occurrence and development of CRC, and further studies are needed to assess causality. Hence, effective periodontal treatment could be a valuable preventive measure for CRC.

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.

The Association between Periodontitis and Human Colorectal Cancer: Genetic and Pathogenic Linkage

Periodontitis has been associated with an increased risk of and mortality associated with human colorectal cancer (CRC). Current evidence attributes such an association to the direct and indirect effects of virulence factors belonging to periodontal pathogens, to inflammatory mediators and to genetic factors. The aims of the study were to assess the existence of a genetic linkage between periodontitis and human CRC, to identify genes considered predominant in such a linkage, thus named leader genes, and to determine pathogenic mechanisms related to the products of leader genes. Genes linking periodontitis and CRC were identified and classified in order of predominance, through an experimental investigation, performed via computer simulation, employing the leader gene approach. Pathogenic mechanisms relating to leader genes were determined through cross-search databases. Of the 83 genes linking periodontitis and CRC, 12 were classified as leader genes and were pathogenically implicated in cell cycle regulation and in the immune-inflammatory response. The current results, obtained via computer simulation and requiring further validation, support the existence of a genetic linkage between periodontitis and CRC. Cell cycle dysregulation and the alteration of the immuno-inflammatory response constitute the pathogenic mechanisms related to the products of leader genes.

Self-reported and clinical periodontal conditions in a group of Eastern European postpartum women

Periodontitis is a highly prevalent condition leading to a continuous destruction of tooth-supporting tissues. It increases the risk for various systemic diseases and adverse pregnancy outcomes. Therefore, screening for periodontitis is important. Screening measures can range from self-reported symptoms to clinical full-mouth periodontal examination. The hypothesis of our study was that self-reported parameters and clinical definition perform equally well in identifying periodontitis patients. The aim of this study was to develop, validate its internal consistency, and evaluate a self-reported instrument against periodontal clinical evaluation for diagnosis of periodontitis in a group of postpartum women, as well as to describe their periodontal status and the risk factors associated with periodontal disease. A cross-sectional study on postpartum women was conducted in a tertiary university hospital, from April 2018 to March 2019. Sociodemographic and behavioral data, periodontal clinical parameters, and self-reported periodontal perception were collected. A 16-item questionnaire was developed to obtain information about perceived periodontal alterations and oral hygiene habits. The utility of the questionnaire was tested against a periodontal diagnosis based on a full-mouth periodontal examination. The questionnaire was applied in 215 postpartum women aged 29.16±5.54 years (mean age (y) ± standard deviation) having the following periodontal status: 16 individuals without periodontal disease (7.44%), 32 individuals with gingivitis (14.88%), 19 individuals with mild periodontitis (8.84%), 132 individuals with moderate periodontitis (61.39%), and 16 individuals with severe periodontitis (7.44%). A significant association was observed between oral hygiene score, smoking status, and periodontal conditions (p<0.05). A significant association between the self-reported items related to “gum swelling”, “halitosis”, “previous periodontal diagnosis” and “previous periodontal treatment” with clinical periodontitis have been identified (p<0.05). Using self-reported questionnaires for detection of periodontal disease was ineffective in our studied population, since self-reported parameters and clinical definition do not appear to perform equally in identifying periodontitis cases. Clinical periodontal examination remains the gold standard for screening. Periodontitis was frequent in our group and the severity was significantly associated with the oral hygiene score and smoking. These results underline the necessity for periodontal clinical examination during pregnancy.

Periodontal Disease, Tooth Loss, and Risk of Serrated Polyps and Conventional Adenomas

Growing data indicate an association between periodontal disease and the development of cancer. However, the evidence for colorectal cancer has been inconsistent and longitudinal study examining its precursor lesions is lacking. We prospectively collected information on periodontal disease and number of tooth loss in the Nurses' Health Study (1992-2002) and the Health Professionals Follow-up Study (1992-2010). Polyp diagnosis was acquired via self-reported questionnaires and confirmed through review of medical records. We used logistic regression to calculate the multivariate-adjusted ORs and 95% confidence intervals (CI) with adjustment for smoking and other known risk factors for periodontal disease and colorectal cancer. In this study, we included 17,904 women and 24,582 men. We documented 2,336 cases of serrated polyps and 4,102 cases of conventional adenomas among 84,714 person-endoscopies throughout follow-up. The ORs of serrated polyps and conventional adenomas comparing individuals with and without periodontal disease were 1.17 (95% CI, 1.06-1.29) and 1.11 (95% CI, 1.02-1.19), respectively. Compared with participants without tooth loss, those who lost ≥4 teeth had 20% (OR, 1.20; 95% CI, 1.03-1.39) greater risk of serrated polyps (P _trend 0.01). Among never smokers, similar associations with periodontal disease were observed for both serrated polyps (OR, 1.20; 95% CI, 1.02-1.41) and conventional adenomas (OR, 1.12; 95% CI, 1.00-1.26). History of periodontal disease and possibly higher number of tooth loss may modestly increase the risk of developing colorectal precursor lesions. Our findings advance our understanding of the interplay between oral health, microbiome, and early colorectal carcinogenesis.

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.

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.

Hematopoietic and lymphatic cancers in patients with periodontitis: a systematic review and meta-analysis

Background

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

Material and Methods

The authors searched relevant studies in databases (PubMed, Web of Science, and MEDLINE). The summary relative risk (RR) along with 95% confidence interval (CI) was calculated by use of random or fixed effects models.

Results

Six studies were included in qualitative synthesis. The pooled analysis revealed that PD was significantly associated with an increased risk of hematopoietic and lymphatic cancers (RR = 1.17; 95% CI = 1.07–1.27; P = 0). Stratified analysis showed the association of PD with hematopoietic and lymphatic cancers remained significant in the never smokers (RR = 1.28; 95% CI = 1.07–1.54; P = 0.007), and in the American population (RR = 1.17; 95% CI = 1.05–1.30; P = 0.003), respectively.

Conclusions

Never smokers population and the American population with PD have a higher risk of developing hematopoietic and lymphatic cancers. PD might be considered as a risk factor for hematopoietic and lymphatic cancers.

Key words:Periodontal disease, hematopoietic and lymphatic cancer, meta-analysis, systematic review.

The association between self-reported poor oral health and gastrointestinal cancer risk in the UK Biobank: A large prospective cohort study

Background

Controversy remains as to whether poor oral health is independently associated with gastrointestinal cancers, due to potential confounding by smoking, alcohol and poor nutrition. The aim of this study was to investigate the association between oral health conditions and gastrointestinal cancer risk.

Methods

Data from the large, prospective UK Biobank cohort, which includes n = 475,766 participants, were analysed. Cox proportional hazard models were applied to estimate the relationship between gastrointestinal cancer risk and self-reported poor oral health (defined as painful gums, bleeding gums and/or having loose teeth), adjusting for confounders.

Results

During an average six years of follow-up, n = 4069 gastrointestinal cancer cases were detected, of which 13% self-reported poor oral health. Overall, there was no association between self-reported poor oral health and risk of gastrointestinal cancer detected (hazard ratio 0.97, 95% confidence interval 0.88-1.07). In site-specific analysis, an increased risk of hepatobiliary cancers was observed in those with self-reported poor oral health (hazard ratio 1.32, 95% confidence interval 0.95-1.80), which was stronger for hepatocellular carcinoma (hazard ratio 1.75, 95% confidence interval 1.04-2.92).

Conclusion

Overall there was no association between self-reported poor oral health and gastrointestinal cancer risk. However, there was a suggestion of an increased risk of hepatobiliary cancer, specifically hepatocellular carcinoma.

Analysis of Fusobacterium nucleatum and Streptococcus gallolyticus in saliva of colorectal cancer patients

Aim: The aim of the study was to examine the prevalence and amount of Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg) and Streptococcus gallolyticus (Sg) in the saliva of colorectal cancer (CRC) patients and controls. Methods: PCR analyses performed in 71 CRC patients and 77 controls. Results: Saliva samples of patients had higher amounts of Fn (p = 0.001) and Sg (p < 0.001) compared with controls. Amount of Fn and Sg were lower in the microsatellite instability (+) group. Evaluation of salivary Sg amount by receiver operating characteristics analysis found to have diagnostic value for CRC (AUC: 0.84, 95% CI: 0.72-0.96). Conclusion: We found higher amounts of Fn and Sg in the saliva of CRC patients. Salivary Sg could helpful in distinction of CRC.

Prospective study of oral microbiome and colorectal cancer risk in low-income and African American populations

Oral microbiome may play an important role in cancer pathogenesis. However, no study has prospectively investigated the association of the oral microbiome with subsequent risk of developing colorectal cancer (CRC). We conducted a nested case-control study including 231 incident CRC cases and 462 controls within the Southern Community Cohort Study with 75% of the subjects being African-Americans. The controls were individually matched to cases based on age, ethnic group, smoking, season-of-study enrollment and recruitment method. Oral microbiota were assessed using 16S rRNA gene sequencing in pre-diagnostic mouth rinse samples. Multiple bacterial taxa showed an association with CRC risk at p <0.05. Oral pathogens Treponema denticola and Prevotella intermedia were associated with an increased risk of CRC, with odds ratios (ORs) and 95% confidence intervals (CIs) of 1.76(1.19-2.60) and 1.55(1.08-2.22), respectively, for the individuals carrying these bacteria compared to non-carriers. In the phylum Actinobacteria, Bifidobacteriaceae was more abundant among CRC patients than among controls. In the phylum Bacteroidetes, Prevotella denticola and Prevotella sp. oral taxon 300 were associated with an increased CRC risk, while Prevotella melaninogenica was associated with a decreased risk of CRC. In the phylum Firmicutes, Carnobacteriaceae, Streptococcaceae, Erysipelotrichaceae, Streptococcus, Solobacterium, Streptococcus sp. oral taxon 058 and Solobacterium moorei showed associations with a decreased risk of CRC. Most of these associations were observed among both African- and European-Americans. Most of the associations were not significant after Bonferroni correction for multiple testing, which may be conservative. Our study suggests that the oral microbiome may play a significant role in CRC etiology.

Association of oral health with lung cancer risk in a low-income population of African Americans and European Americans in the Southeastern United States

OBJECTIVES

Previous studies have suggested that poor oral health might increase the risk of lung cancer among European- and Asian- descendants. The association has not been investigated among African Americans or socially disadvantaged populations. In this nested case-control study, we investigated whether oral health was associated with lung cancer risk among a low-income population of African Americans and European Americans in the Southeastern United States.

MATERIALS AND METHODS

A total of 403 incident lung cancer cases and 1612 matched controls from the Southern Community Cohort Study were included. Multivariate conditional logistic regression models were fitted to evaluate the risk of lung cancer linked to tooth loss, tooth decay, and history of periodontal disease.

RESULTS

Tooth loss was significantly associated with an increased risk of lung cancer: the odds ratio (OR) of more than 10 teeth lost was 1.64 (95% CI: 1.00, 2.69). Tooth decay was also significantly associated with increased lung cancer risk; those with ≥ 6 decaying teeth had an OR of 1.65 (1.18, 2.31). An increased lung cancer risk was significantly associated with a history of periodontal disease among African Americans (OR = 1.56, 95% CI: 1.05, 2.31) and heavy smokers (OR = 2.05, 95% CI: 1.38, 3.05).

CONCLUSION

Poor oral health is associated with increased lung cancer risk, and this association appears to vary by race and smoking behavior among a low-income population of African Americans and European Americans in the Southeastern United States.

Periodontal disease and susceptibility to breast cancer: A meta-analysis of observational studies

OBJECTIVE

While some individual studies have suggested an association between periodontal disease and breast cancer, there has not been a formal meta-analysis that collates the existing evidence supporting the hypothesis that periodontal disease leads to a higher risk of developing breast cancer. Accordingly, this meta-analysis was conducted.

METHODS

Relevant studies published until April 2018 were retrieved and were screened according to established inclusion criteria. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated to assess the association between periodontal disease and the risk of breast cancer and fixed effect models were used according to the results of the heterogeneity test.

RESULTS

Eight studies, involving 168,111 individuals, were identified as having explored the association between periodontal disease and breast cancer. Summary estimates in view of adjusted data showed that periodontal disease did increase susceptibility to breast cancer (RR = 1.18, 95%CI: 1.11-1.26, I²  = 17.6%), with robust results confirmed by sensitivity analysis.

CONCLUSION

Our results provided evidence of a modest positive association between periodontal disease and breast cancer. Implementation of practical measures to prevent and treat periodontal disease is of great public health significance. Moreover, additional studies are recommended to explore this topic in more detail.

Severity of chronic periodontitis and risk of gastrointestinal cancers: A population-based follow-up study from Taiwan

The present study aimed to assess the association between the severity of chronic periodontitis and the risk of gastrointestinal (GI) cancers by investigating whether severe chronic periodontitis (CP), rather than mild CP, correlates with an increased risk of total or individual GI cancers.Adults (≥18 years) with mild and severe CP were identified from a random sample of 2 million insured patients in the National Health Insurance Research Database (2001-2010). After propensity score matching, 25,485 individuals, each with mild or severe CP, were included for comparison. The primary endpoint was the incidence of total or individual GI cancers, including cancers of the esophagus, stomach, small intestine, colon/rectum, and pancreas. Cox proportional hazard models with the robust aggregated sandwich estimator were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) after adjusting for known risk factors.GI cancers occurred in 275 individuals with mild CP and 324 individuals with severe CP. After adjusting for known risk factors, severe CP was not associated with an increased risk of total GI cancer relative to mild CP (HR: 0.99, 95% CI: 0.84-1.16) or individual GI cancers, including esophageal (HR: 1.15, 95% CI: 0.62-2.15), gastric (HR: 1.01, 95% CI: 0.68-1.49), small intestinal (HR: 0.70, 95% CI: 0.22-2.22), colorectal (HR: 0.95, 95% CI: 0.78-1.16), and pancreatic cancers (HR: 0.90, 95% CI: 0.47-1.75).Severe CP was not associated with an increased risk of total or individual GI cancers when compared with mild CP.

Periodontal Disease, Tooth Loss, and Cancer Risk

Periodontal disease, which includes gingivitis and periodontitis, is highly prevalent in adults and disease severity increases with age. The relationship between periodontal disease and oral cancer has been examined for several decades, but there is increasing interest in the link between periodontal disease and overall cancer risk, with systemic inflammation serving as the main focus for biological plausibility. Numerous case-control studies have addressed the role of oral health in head and neck cancer, and several cohort studies have examined associations with other types of cancers over the past decade. For this review, we included studies that were identified from either 11 published reviews on this topic or an updated literature search on PubMed (between 2011 and July 2016). A total of 50 studies from 46 publications were included in this review. Meta-analyses were conducted on cohort and case-control studies separately when at least 4 studies could be included to determine summary estimates of the risk of cancer in relation to 1) periodontal disease or 2) tooth number (a surrogate marker of periodontal disease) with adjustment for smoking. Existing data provide support for a positive association between periodontal disease and risk of oral, lung, and pancreatic cancers; however, additional prospective studies are needed to better inform on the strength of these associations and to determine whether other cancers are associated with periodontal disease. Future studies should include sufficiently large sample sizes, improved measurements for periodontal disease, and thorough adjustment for smoking and other risk factors.

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

Background

Previous studies have indicated that tooth loss is associated with colorectal cancer risk but have presented controversial results.

Methods

We conducted a dose–response meta-analysis in order to investigate the correlation between tooth loss and colorectal cancer risk. Up to August 2017, six eligible studies were included in this meta-analysis.

Results

Our results showed statistically significant association between tooth loss and colorectal cancer (OR =1.08, 95% CI: 1.03–1.15, P<0.001). In addition, we obtained the best fit at an inflection point of every two tooth loss in piecewise regression analysis, and the summary relative risk (RR) of colorectal cancer for an increase of every two tooth loss was 1.06 (95% CI: 1.02–1.11, P<0.001). Furthermore, tooth loss was significantly associated with colorectal cancer risk in Caucasia (RR: 1.18; 95% CI: 1.09–1.28; P<0.001) and Asia (RR: 1.06; 95% CI: 1.02–1.10; P<0.001). Moreover, tooth loss was significantly associated with a higher risk of colon cancer (RR: 1.09; 95% CI: 1.02–1.17; P<0.001) and rectal cancer (RR: 1.08; 95% CI: 1.01–1.17; P<0.001).

Conclusion

Subgroup meta-analyses showed consistency with the primary findings. Considering these promising results, increasing tooth loss may be harmful to our health, and maintenance of our oral health is essential.

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

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

Increased cancer risk in patients with periodontitis

BACKGROUND

Previous studies have noted a possible association between periodontal diseases and the risk of various cancers. We assessed cancer risk in a cohort of patients with moderate to severe periodontitis.

METHODS

Patients diagnosed with moderate to severe periodontitis by a periodontist between 2001 and 2010 were identified from the hospital registry. Patients younger than 35 years of age or with a prior cancer diagnosis were excluded. The age- and gender-standardized incidence rates (SIR) were calculated by dividing the number of observed cases by the number of expected cases from Turkish National Cancer Registry 2013 data.

RESULTS

A total of 280 patients were included (median age 49.6, 54% female). Median follow-up was 12 years. Twenty-five new cancer cases were observed. Patients with periodontitis had 77% increased risk of cancer (SIR 1.77, 95% CI 1.17-2.58, p = .004). Women with periodontitis had significantly higher risk of breast cancer (SIR 2.40, 95% CI 0.88-5.33) and men with periodontitis had significantly higher risk of prostate cancer (SIR 3.75, 95% CI 0.95-10.21) and hematological cancers (SIR 6.97, 95% CI 1.77-18.98).

CONCLUSION

Although showing a causal association necessitates further investigation, our results support the idea that periodontitis might be associated with increased cancer risk, particularly with hematological, breast and prostate cancers.