Smoking, alcohol, dentition and diet in the epidemiology of oral cancer

Dental Caries and Periodontal Disease Status in Patients with Oral Squamous Cell Carcinoma: A Screening Study in Urban and Semiurban Population of Karnataka

OBJECTIVES

To test the validity of numerous anecdotal claims of poor oral hygiene status being a contributory or etiology for Oral Squamous Cell Carcinoma (OSCC) and to isolate the microorganisms associated with oral cancer, to elucidate their role if any, in oral cancer.

MATERIALS AND METHODS

A total of 242 OSCC patients and 254 controls were screened. Questionnaires were used to inquire about the past condition of the oral health. Dental caries, oral hygiene status and periodontal disease status were assessed using indices. Microorganisms were identified by bacterial culture methods.

RESULTS

Majority of cases (Group-1) (57.85 %) never visited the dentist compared to controls (Group-2) (46.06 %). Group-1 brushed once in a day (93.4 %) and less often twice a day (6.6 %) compared to Group-2 (81.1 % and 18.9 %). There was no significant difference in caries experience in both groups. Teeth missing due to periodontal reasons were more in Group-1 (40 %) than Group-2 (26 %) (p < 0.002). Poor oral hygiene and increased pocket depth were seen in Group-1 than in Group-2 (p < 0.001). Streptococcus species (α-hemolytic) followed by Staphylococcus species were the predominant microorganisms isolated from Group-1 compared to Group-2 with (62 % vs. 66 %) and without habits (40 % vs. 66 %).

CONCLUSION

Tobacco consumption, lack of dental visits and infrequent brushing are significantly associated with increased risk of oral cancer. There seems to be no association between dental caries and OSCC. However, periodontal disease experience is directly proportional to OSCC. Increased pathogenic flora may produce carcinogenic metabolites or post-operative infections.

Poor oral Hygiene may be the Sole Cause of Oral Cancer

PURPOSE

The purpose of this case-control study was to draw attention to the possibility that poor oral hygiene resulting from infrequent and inadequate use of chewing sticks might be the sole cause of oral cancer in 60 patients investigated in the maxillofacial units of two specialist hospitals in eastern Nigeria.

METHODS

Sixty cases and 60 controls made up the study population. We matched them for age, gender, period of admission and study site. The interview of all the participants contained data on demographic factors, family history of cancer, tobacco habits, oral hygiene, dietary habits and use of alcohol. We took biopsies of the lesions for histo-pathological examination. We entered the collected data into Microsoft excel package and transported it to Stata for generation of statistical test.

RESULT

Poor oral hygiene due to infrequent tooth brushing was associated with primary oral cancer in this patient sample. On the other hand, frequent tooth brushing was related to healthy status.

CONCLUSION

In the absence of other known carcinogens, poor oral hygiene may be the single factor that caused oral cancer in these subjects. Research is needed to investigate the pathological mechanism that is associated with this risk factor.

Interaction between Chronic Inflammation and Oral HPV Infection in the Etiology of Head and Neck Cancers

Incidences of oral tongue, base of the tongue, and tonsil cancers have been increasing steadily in many parts of the world in spite of declining rates of tobacco use over the last four decades. A better understanding of the etiology, interactions between risk factors, and new approaches to prevention and treatment are necessary to change this course. This paper will present evidence supporting a potential role of chronic inflammation in the etiologies of oral human papillomavirus infection and head and neck squamous cell carcinoma, and it will discuss the implications for prevention and treatment.

Niacin requirements for genomic stability

Through its involvement in over 400 NAD(P)-dependent reactions, niacin status has the potential to influence every area of metabolism. Niacin deficiency has been linked to genomic instability largely through impaired function of the poly ADP-ribose polymerase (PARP) family of enzymes. In various models, niacin deficiency has been found to cause impaired cell cycle arrest and apoptosis, delayed DNA excision repair, accumulation of single and double strand breaks, chromosomal breakage, telomere erosion and cancer development. Rat models suggest that most aspects of genomic instability are minimized by the recommended levels of niacin found in AIN-93 formulations; however, some beneficial responses do occur in the range from adequate up to pharmacological niacin intakes. Mouse models show a wide range of protection against UV-induced skin cancer well into pharmacological levels of niacin intake. It is currently a challenge to compare animal and human data to estimate the role of niacin status in the risk of genomic instability in human populations. It seems fairly certain that some portion of even affluent populations will benefit from niacin supplementation, and some subpopulations are likely well below an optimal intake of this vitamin. With exposure to stressors, like chemotherapy or excess sunlight, suraphysiological doses of niacin may be beneficial.

Streptococci-human papilloma virus interaction with ethanol exposure leads to keratinocyte damage

PURPOSE

Ethanol, human papilloma virus (HPV), and poor oral hygiene are risk factors that have been attributed to oral carcinogenesis. Streptococci sp and HPV infections are common in the head and neck, often associated with sexual activity. Although HPV is linked to head and neck squamous cell carcinoma, it is unclear whether there is a similar role for Streptococci sp. This cell study examines whether Streptococci sp and HPV-16 with exposure to ethyl alcohol (ETOH) can act as cofactors in the malignant transformation of oral keratinocytes.

MATERIALS AND METHODS

ETOH (0.1%-20% vol/vol) was used to investigate Streptococci sp attachment with immortalized E6-expressing HPV/HOK-16B cells, human oral buccal keratinocytes, and foreskin keratinocytes. Streptococci sp (Streptococci mutans [LT11]) and various strains of acetaldehyde (AA) producer and nonproducer Streptococcus salivarius (110-1, 109-2, 101-7, and 107-1) and a lactic acid producer bacterium, Lactobacillus rhamnosus (24-1 and 25-2), were examined for interactions with keratinocytes by use of a green dye (percent of cells with colonies after 24 hours). Carcinogens, AA, malondialdehyde, DNA damage, and proliferation (5'-bromo-2-deoxyuridine) among keratinocytes were also quantified.

RESULTS

AA and malondialdehyde production from permissible Streptococci sp significantly increased with attachment to keratinocytes, whereas L rhamnosus did not significantly attach to keratinocytes. This attachment was associated with enhanced levels of AA adduct formation, proliferation (5'-bromo-2-deoxyuridine incorporation), and enhanced migration through integrin-coated basement membrane by HPV oral keratinocytes, which are characteristics of a malignant phenotype.

CONCLUSIONS

These cell studies suggest that oral Streptococci sp and HPV (HPV-16) cooperate to transform oral keratinocytes after low-level ETOH (1%) exposure. These results appear to suggest a significant clinical interaction, but further validation is warranted.

Are oral and dental diseases linked to cancer?

OBJECTIVE

Infection and inflammation play a role in carcinogenesis, and highly prevalent oral and dental diseases have been significantly linked to some types of cancer. This article reviews current literature in this area.

MATERIALS AND METHODS

Open literature review using the PubMed database and focused on publications from 2000 to 2010.

RESULTS

Numerous potential mechanisms are implicated in the oral disease/carcinogenesis paradigm, including infection- and inflammation-associated cell pathology and microbial carcinogen metabolism. Poor oral hygiene is associated with oral cancer, but there is also evidence of a possible link between oral or dental infections and malignancies in general.

CONCLUSION

Oral infections may trigger malignant transformation in tissues of the mouth and other organs. However, scientific evidence to date remains weak and further well-conducted studies are warranted before cancer can be properly added to the list of oral infection-related systemic diseases.

Chloride intracellular channel 1 identified using proteomic analysis plays an important role in the radiosensitivity of HEp-2 cells via reactive oxygen species production

The nature of the molecules underlying the radioresistance phenotype of laryngeal cancer cells remains to be established. We initially generated radioresistant laryngeal cancer cell lines from human HEp-2 cells with fractionated radiation. These RR-HEp-2 cells and isolated clones displayed more radioresistant and anti-apoptotic phenotypes than parental HEp-2 cells after radiation. Characteristics of RR-Hep-2 cell lines were confirmed by upregulation of radioresistance-related genes, such as epidermal growth factor receptor, Hsp90, and Bcl-xl. Subsequently, we examined proteome changes between HEp-2 and RR-HEp-2 cells and identified 16 proteins showing significantly altered expression levels. Interestingly, protein expression of chloride intracellular channel 1 (CLIC1) was markedly suppressed in RR-HEp-2 cells, compared with non-irradiated control cells. Suppression of CLIC1 with an indanyloxyacetic acid-94 or small interfering RNA led to radioresistance in HEp-2 cells by suppressing the radiation-induced cellular ROS level. However, ectopic overexpression of CLIC1 induced radiosensitivity in RR-HEp-2 cells via induction of ROS level after radiation, suggesting that the protein acts as a positive regulator of ROS production. Our results collectively indicate that suppression of CLIC1 contributes to acquisition of the radioresistance phenotype of laryngeal cancer cells via inhibition of ROS production, implying that this protein is an important candidate molecule for radiotherapy in radioresistant laryngeal cancer cells.

Alcohol consumption and cancers of the oral cavity and pharynx from 1988 to 2009: an update

Evidence for the human carcinogenic effects of alcohol consumption on the risk of cancers of the oral cavity and pharynx has been considered sufficient in the International Agency for Research on Cancer Monograph 44 on alcohol and cancer in 1988. We evaluated human carcinogenic evidence related to the risk of oral and pharyngeal cancers based on cohort and case-control studies published from 1988 to 2009. A large body of evidence from epidemiological studies of different designs and conducted in different populations has consistently supported the fact that alcohol consumption is strongly associated with an increase in the risk of oral and pharyngeal cancers. The relative risks are 3.2-9.2 for more than 60 g/day (or more than four drinks/day) when adjusted for tobacco smoking and other potential confounders. A strong dose-response effect on the intensity of alcohol use is reported in most of the studies. However, no apparent association is observed for the duration of alcohol use. Compared with current alcoholics, a decreased risk of approximately 10 to 15 years is associated with alcohol cessation. Similar associations have been observed among nonsmokers in over 20 studies. In general, the dominant type of alcohol consumption in each population is associated with the greatest increase in risk. A large number of studies on joint exposure to alcohol and tobacco consumption show a greater than multiplicative synergistic effect.

Oral health and risk for head and neck squamous cell carcinoma: the Carolina Head and Neck Cancer Study

OBJECTIVE

Recent reports have linked oral health and periodontal disease indicators with increased risk of squamous cell carcinoma of head and neck (SCCHN). Thus far, evidence has been inconclusive; our objective was to study the association between oral health and SCCHN risk in the context of a large population-based study.

METHODS

A population-based case-control study of incident SCCHN, the Carolina Head and Neck Cancer Study was carried out in 2002-2006 in 46 counties in North Carolina. Controls (n = 1,361) were frequency matched with cases (n = 1,289) on age, race, and gender. Oral health was assessed using interview data on tooth loss and mobility, mouthwash use, and frequency of dental visits.

RESULTS

Subjects were 26-80 years old (median age = 61). The distribution of tooth loss among controls was 0-5 teeth = 60%; 5-14 = 15%; and 16-28 = 25%. After controlling for covariates, tooth loss did not yield any notable association with SCCHN (16-28 vs. 0-5 lost teeth: OR: 1.21, 95% CI: 0.94, 1.56). Self-reported history of tooth mobility was moderately associated with increased SCCHN risk (OR: 1.33, 95% CI: 1.07, 1.65); however, the association did not persist among never smokers. Routine dental visits were associated with 30% risk reduction (OR: 0.68, 95% CI: 0.53, 0.87).

CONCLUSIONS

These data provide support for a possible modest association of periodontal disease, as measured by self-reported tooth loss indicators, but not tooth loss per se, with SCCHN risk.

Feline head and neck squamous cell carcinoma: a natural model for the human disease and development of a mouse model

Head and neck squamous cell carcinoma (H/N SCC) is a devastating disease in humans and cats, and shares similar features between the two species. The large population of pet cats in the United States, along with the high incidence of oral SCC in the cat, makes the cat an attractive candidate as a natural model for the human disease. There are similarities in pathology, progression, outcome, resistance to treatment, possible aetiologies and p53 expression, and we discuss the benefits of the cat as a natural model. We describe the development of a nude mouse xenograft model of feline oral SCC using the SCCF1 cell line transfected with a luciferase expression construct. In vivo tumour growth and metastasis were measured using serial bioluminescent imaging, and tumours grew best in the subcutis. The cat and nude mouse models will be useful to investigate the pathogenesis and the molecular basis of H/N SCC, and for preclinical drug screening.

Chronic periodontitis and the incidence of head and neck squamous cell carcinoma

Substantial evidence supports an association between chronic infections/inflammation, and cancer. The aim of this study was to assess the effect of chronic periodontitis on head and neck squamous cell carcinoma (HNSCC). The study population consisted of new patients at the Department of Dentistry and Maxillofacial Prosthetics, Roswell Park Cancer Institute between 1999 and 2005. Cases were patients diagnosed with primary HNSCC. Controls were all patients seen during the same time period but negative for malignancy. Patients age <21 years, edentulous, immunocompromised, and those with history of cancer were excluded. Periodontitis was measured by alveolar bone loss (ABL) from panoramic radiographs by one examiner blind to cancer status. A total of 473 patients (266 cases and 207 controls) were included in the study. Each millimeter of ABL was associated with >4-fold increased risk of HNSCC (odds ratio, 4.36; 95% confidence interval, 3.16-6.01) after adjustment for age, gender, race/ethnicity, marital status, smoking status, alcohol use, and missing teeth. The strength of the association was greatest in the oral cavity, followed by oropharynx and larynx. The association persisted in subjects who never used tobacco and alcohol. There was a significant interaction between smoking and ABL (P = 0.03). Patients with periodontitis were more likely to have poorly differentiated oral cavity SCC than those without periodontitis (32.8% versus 11.5%; P = 0.038). This study suggests that chronic periodontitis is an independent risk factor for HNSCC and smoking modifies this association. These results have implications for practical and safe strategies for prevention, diagnosis, and treatment of HNSCC.

Causes of oral cancer--an appraisal of controversies

Major risk factors for oral cancer are cigarette smoking and alcohol misuse. Among Asian populations, regular use of betel quid (with or without added tobacco) increases oral cancer risks. Dentists should be aware of some emerging risk factors for oral, and particularly oropharyngeal cancer such as the role of the human papillomavirus infection (HPV). Decreases in risk could be achieved by encouraging high fruit and vegetable consumption. Some controversies related to the aetiology of this disease also need clarification. The objective of this paper is to provide an opinion on these debated controversies.

Human papillomavirus in early laryngeal carcinoma

OBJECTIVES/HYPOTHESIS

To examine the role of HPV status in the etiology, prognosis, and treatment of head and neck squamous cell carcinoma in early larynx malignancies.

STUDY DESIGN

Retrospective.

METHODS

Thirty-eight cases of T1 or carcinoma in situ (CIS) laryngeal lesions were examined for the presence of human papilloma virus (HPV) using an inclusive polymerase chain reaction (PCR)/hybridization technique capable of identifying 37 HPV subtypes.

RESULTS

HPV DNA was detected in 6 (16%) of the 38 lesions, representing HPV types 16, 26, 31, 39, and 52, and p16 tumor suppressor protein expression was confirmed in 10 representative cases. This HPV prevalence is higher than that noted in many previous laryngeal cancer studies, possibly due to the relatively large panel of subtypes screened for in this study. Identification of HPV-26, which has been associated with uterine cervical cancer, in an early laryngeal cancer specimen represents the first evidence of this subtype in a laryngeal carcinoma. Consistent with reports focusing on head and neck squamous cell carcinoma (HNSCC) arising from other subsites within the upper aerodigestive tract, patients with HPV-positive laryngeal carcinomas were of younger age and were somewhat less likely to have a history of tobacco use, although the latter of the two findings did not reach statistical significance.

CONCLUSIONS

Our findings emphasize the presence of a broad spectrum of HPV types in a relevant proportion of early laryngeal cancers, and together with evidence of an association of HPV tumor status with a more favorable clinical course, provide a rationale for the routine HPV testing of small larynx lesions.

Systematic review of the relation between smokeless tobacco and cancer in Europe and North America

BACKGROUND

Interest is rising in smokeless tobacco as a safer alternative to smoking, but published reviews on smokeless tobacco and cancer are limited. We review North American and European studies and compare effects of smokeless tobacco and smoking.

METHODS

We obtained papers from MEDLINE searches, published reviews and secondary references describing epidemiological cohort and case-control studies relating any form of cancer to smokeless tobacco use. For each study, details were abstracted on design, smokeless tobacco exposure, cancers studied, analysis methods and adjustment for smoking and other factors. For each cancer, relative risks or odds ratios with 95% confidence intervals were tabulated. Overall, and also for USA and Scandinavia separately, meta-analyses were conducted using all available estimates, smoking-adjusted estimates, or estimates for never smokers. For seven cancers, smoking-attributable deaths in US men in 2005 were compared with deaths attributable to introducing smokeless tobacco into a population of never-smoking men.

RESULTS

Eighty-nine studies were identified; 62 US and 18 Scandinavian. Forty-six (52%) controlled for smoking. Random-effects meta-analysis estimates for most sites showed little association. Smoking-adjusted estimates were only significant for oropharyngeal cancer (1.36, CI 1.04-1.77, n = 19) and prostate cancer (1.29, 1.07-1.55, n = 4). The oropharyngeal association disappeared for estimates published since 1990 (1.00, 0.83-1.20, n = 14), for Scandinavia (0.97, 0.68-1.37, n = 7), and for alcohol-adjusted estimates (1.07, 0.84-1.37, n = 10). Any effect of current US products or Scandinavian snuff seems very limited. The prostate cancer data are inadequate for a clear conclusion.Some meta-analyses suggest a possible effect for oesophagus, pancreas, larynx and kidney cancer, but other cancers show no effect of smokeless tobacco. Any possible effects are not evident in Scandinavia. Of 142,205 smoking-related male US cancer deaths in 2005, 104,737 are smoking-attributable. Smokeless tobacco-attributable deaths would be 1,102 (1.1%) if as many used smokeless tobacco as had smoked, and 2,081 (2.0%) if everyone used smokeless tobacco.

CONCLUSION

An increased risk of oropharyngeal cancer is evident most clearly for past smokeless tobacco use in the USA, but not for Scandinavian snuff. Effects of smokeless tobacco use on other cancers are not clearly demonstrated. Risk from modern products is much less than for smoking.

Is the presence of Helicobacter pylori in dental plaque of patients with chronic periodontitis a risk factor for gastric infection?

BACKGROUND

Helicobacter pylori is considered to be a pathogen responsible for gastritis and peptic ulcers, and a risk factor for gastric cancer. A periodontal pocket in the teeth of individuals with chronic periodontitis may function as a reservoir for H pylori.

OBJECTIVE

The present study was undertaken to evaluate whether the presence of H pylori in the dental plaque of patients with and without periodontitis correlates with gastric involvement.

METHODS

A total of 101 patients with dyspepsia were included in the present study. Subjects were divided into periodontitis and nonperiodontitis groups. For the detection of H pylori in dental plaque, samples were collected from two teeth using a periodontal curette. Subgingival plaque was obtained by inserting two sterile paper points into periodontal pockets for 20 s. This was followed by an upper gastrointestinal endoscopy and antral biopsies.

RESULTS

Sixty-five per cent of patients had dental plaque positive for H pylori and more than 50% harboured the bacteria in their stomach. Periodontitis patients had a significantly higher percentage of H pylori in their dental plaque (79% versus 43%; P<0.05) and the stomach (60% versus 33%; P<0.05) than patients with no periodontitis. Additionally, 78% of patients from the periodontitis group versus only 30% from the nonperiodontitis group had a positive test result for the coexistence of H pylori in both dental plaque and the stomach.

CONCLUSION

Patients with poor oral hygiene have a higher prevalence of H pylori in dental plaque and in the stomach. This finding suggests that the oral cavity may be a reservoir for H pylori, and potentially a source of transmission or reinfection.

Alcohol intake and oral cavity cancer risk among men in a prospective study in Kerala, India

OBJECTIVE

The aim of the study was to evaluate the role of alcohol drinking and patterns of consumption in oral cancer incidence and mortality in a cohort study using data from the Trivandrum Oral Cancer Screening Study, India.

METHODS

At baseline, the study participants completed a lifestyle questionnaire including items on frequency and duration of alcohol consumption. They were followed up for oral cancer incidence and mortality. Data from 32 347 subjects, of whom 134 eventually developed oral cancer, were analysed to estimate risk of oral cancer incidence and mortality according to drinking patterns, using a Cox regression model adjusted for age, religion, education, occupation, body mass index (BMI), standard of living index, chewing habits, smoking habits, and vegetable and fruit intake.

RESULTS

Current and past drinkers were each associated with significantly increased risk of developing oral cancer. The hazard ratio increased significantly by 49% (95% CI = 1-121%) among current drinkers and 90% (95% CI = 13-218%) among past drinkers. A significant dose-response relationship between intake frequency, duration and oral cancer risk (incidence and mortality) was observed.

CONCLUSIONS

As with other lifestyle factors, alcohol intake plays an important role in oral carcinogenesis in this population, and understanding this role is relevant to developing public health policies targeting at-risk population.

Dairy products, leanness, and head and neck squamous cell carcinoma

BACKGROUND

As part of a population-based case-control study, we investigated the association of food groups and micronutrients estimated from a validated food frequency questionnaire (FFQ) with the risk of development of head and neck squamous cell carcinoma (HNSCC).

METHODS

Incident cases were accrued through Boston area hospitals from 1999 to 2003, and neighborhood controls were selected and matched by location, age, and sex. There were 504 cases and 717 controls enrolled, who completed the FFQ.

RESULTS

We observed a positive association between the consumption of dairy products and HNSCC. The odds of HNSCC in the highest quintile of dairy intake was 1.64 (95% CI: 1.09-2.46), compared with subjects in the lowest quintile. There was a significant association between leanness with HNSCC. The odds of cancer among the leanest subjects was 5.8 (95%CI: 3.2-10.6) compared with a healthy BMI. Finally, intake of animal fat was positively associated with an elevation in cancer risk. The odds of HNSCC for high animal fat intake were 1.50 (0.99-2.27).

CONCLUSIONS

Our data suggest that consumption of fruits and vegetables is not universally protective for HNSCC and that other food groups and nutrients may influence the risk for developing this disease.

A review of the relationship between tooth loss, periodontal disease, and cancer

Recent studies have investigated the association between periodontal disease, tooth loss, and several systemic diseases including cancer, cardiovascular disease, and preterm birth. Periodontal disease, a chronic inflammatory condition, is highly prevalent in adult populations around the world, and may be preventable. Estimates of prevalence vary between races and geographic regions, with a marked increase in the occurrence of periodontal disease with advancing age. Worldwide estimates for the prevalence of severe periodontal disease generally range from 10 to 15%. The relationship between oral health and cancer has been examined for a number of specific cancer sites. Several studies have reported associations between periodontal disease or tooth loss and risk of oral, upper gastrointestinal, lung, and pancreatic cancer in different populations. In a number of studies, these associations persisted after adjustment for major risk factors, including cigarette smoking and socioeconomic status. This review provides a summary of these findings, discusses possible biological mechanisms involved, and raises methodological issues related to studying these relationships.

Periodontal disease, tooth loss, and cancer risk in male health professionals: a prospective cohort study

BACKGROUND

Studies suggest that tooth loss and periodontal disease might increase the risk of developing various cancers; however, smoking might have confounded the reported associations. We aimed to assess whether periodontal disease or tooth loss is associated with cancer risk.

METHODS

The analysis was done in a prospective study (the Health Professionals Follow-Up Study [HPFS]), which was initiated in 1986 when US male health professionals aged 40-75 years responded to questionnaires posted by the Department of Nutrition, Harvard University School of Public Health, Boston, MA, USA. In addition to the baseline questionnaires, follow-up questionnaires were posted to all living participants every 2 years and dietary questionnaires every 4 years. At baseline, participants were asked whether they had a history of periodontal disease with bone loss. Participants also reported number of natural teeth at baseline and any tooth loss during the previous 2 years was reported on the follow-up questionnaires. Smoking status and history of smoking were obtained at baseline and in all subsequent questionnaires. Additionally at baseline, participants reported their mean frequency of food intake over the previous year on a 131-item semiquantitative food-frequency questionnaire. Participants reported any new cancer diagnosis on the follow-up questionnaires. Endpoints for this study were risk of total cancer and individual cancers with more than 100 cases. Multivariate hazard ratios (HRs) and 95% CIs were calculated by use of Cox proportional hazard models according to periodontal disease status and number of teeth at baseline.

FINDINGS

In the main analyses, 48 375 men with median follow-up of 17.7 years (1986 to Jan 31, 2004) were eligible after excluding participants diagnosed with cancer before 1986 (other than non-melanoma skin cancer, n=2076) and those with missing data on periodontal disease (n=1078). 5720 incident cancer cases were documented (excluding non-melanoma skin cancer and non-aggressive prostate cancer). The five most common cancers were colorectal (n=1043), melanoma of the skin (n=698), lung (n=678), bladder (n=543), and advanced prostate (n=541). After adjusting for known risk factors, including detailed smoking history and dietary factors, participants with a history of periodontal disease had an increased risk of total cancer (HR 1.14 [95% CI 1.07-1.22]) compared with those with no history of periodontal disease. By cancer site, significant associations for those with a history of periodontal disease were noted for lung (1.36 [1.15-1.60]), kidney (1.49 [1.12-1.97]), pancreas (1.54 [1.16-2.04]; findings previously published), and haematological cancers (1.30 [1.11-1.53]). Fewer teeth at baseline (0-16) was associated with an increase in risk of lung cancer (1.70 [1.37-2.11]) for those with 0-16 teeth versus those with 25-32 teeth. In never-smokers, periodontal disease was associated with significant increases in total (1.21 [1.06-1.39]) and haematological cancers (1.35 [1.01-1.81]). By contrast, no association was noted for lung cancer (0.96 [0.46-1.98]).

INTERPRETATION

Periodontal disease was associated with a small, but significant, increase in overall cancer risk, which persisted in never-smokers. The associations recorded for lung cancer are probably because of residual confounding by smoking. The increased risks noted for haematological, kidney, and pancreatic cancers need confirmation, but suggest that periodontal disease might be a marker of a susceptible immune system or might directly affect cancer risk.

Current topics in the epidemiology of oral cavity and oropharyngeal cancers

Oral cancer incidence rates rose dramatically during the twentieth century in the United States and Europe, especially among individuals under the age of 60 years. Although influenced by age, sex, and country of origin, incidence trends were most strongly affected by elevated risk among individuals born after approximately 1915. This cohort effect was indicative of strong behavioral influences on oral cancer risk. In this article, associations between oral cancer risk and established behavioral risk factors including alcohol and tobacco use are reviewed. Additionally, possible associations between oral cancer risk and oral hygiene, diet, nutritional status, and sexual behavior as well as the influence of genetic factors on oral cancer risk are considered. Special emphasis is placed on evaluating possible risk differences in individuals above and below the age of 45 and in users and nonusers of alcohol and tobacco.

Utility of toluidine blue in oral premalignant lesions and squamous cell carcinoma: Continuing research and implications for clinical practice

Toluidine blue (TB) has been shown to aid in the detection and diagnosis of oropharyngeal squamous cell carcinoma (OSCC) and oral premalignant lesions (OPLs). TB has been shown to enhance visualization of oral lesions and assist in identifying sites of increased risk of dysplastic/malignant change and promote biopsy. TB has been shown to identify lesions with molecular changes associated with risk of progression of OPLs to OSCC. A recent prospective longitudinal study showed TB retention in histologic benign lesions and lesions with mild dysplasia that are at increased risk of progression to cancer. Clinical trials show that TB is useful in identifying asymptomatic OSCC and premalignant lesions at risk of progressing to SCC, which might otherwise be undetected until lesions become more advanced. The data supports TB use in oral examination of patients at risk of OSCC.

Role of nitric oxide in the development of distant metastasis from squamous cell carcinoma

BACKGROUND

Metastasis, the dissemination of malignant cells to distant sites, remains one of the most significant factors responsible for death from cancer. Recent studies have shown some improvement in the rate of distant metastasis (DM) with the addition of chemotherapy to surgery and radiation for treatment of head and neck squamous cell carcinoma (HNSCC). However, diagnosis and treatment at an early stage ultimately leads to a better prognosis. The prediction of which patients will develop metastasis and the selection of treatment most effective at preventing and treating metastasis remains dependent on an incomplete understanding of prognostic factors and the biological and molecular basis for metastatic development. This study was undertaken using an in vivo model to investigate the possible role of nitric oxide (NO) in the development of metastasis from HNSCC. The findings will result in better understanding of the metastatic process for HNSCC, with the potential to develop and implement therapies that could prevent and treat metastasis in patients.

OBJECTIVES/HYPOTHESIS

1) To analyze whether in vivo videomicroscopy (IVVM) is useful for the study of DM from squamous cell carcinoma of the head and neck; 2) with use of IVVM, investigate the effect of the biological mediators NO and interleukin (IL)-1 on the adhesion of circulating human HNSCC cells in the hepatic microcirculation.

STUDY DESIGN

Prospective study using an animal model.

METHODS

Phase 1: athymic nude rats and mice were used for IVVM experiments. The cremaster muscle and liver, used as arterial and venous flow models, were tested to determine whether IVVM was useful for the study of human HNSCC interactions with the microcirculation. A human squamous cell carcinoma cell line (FaDu) labeled with the intracytoplasmic fluorescent marker BCECF-am. was used for all experiments. Videomicroscopic images of FaDu cells in the microcirculation were analyzed for cell adhesion, morphology, deformation, circulation, location of adhesion within the microcirculation, and alteration of microvascular circulation. Phase 2: the effect of IL-1, NO, and NO inhibitors on HNSCC cell adhesion in the hepatic microcirculation of nude mice was analyzed by IVVM. This was followed by histologic determination of the ratio of FaDu cells present for liver area analyzed. Nude mice were treated with 1) IL-1; 2) L-arginine (an NO substrate); or 3) L-N-monomethyl-L-arginine (an NO synthase inhibitor) alone or in combination. These data were analyzed statistically to determine the effect on cell adhesion in the liver.

RESULTS

IVVM provided a method for the study of circulating HNSCC with the microcirculation in both the cremaster and liver models. FaDu cells were arrested at the inflow side of the circulation, with maintenance of cell integrity. L-arginine and IL-1 both increased FaDu cell arrest in the liver above baseline (P = .00008 and P = .03), and the combination of these agents potentiated the effect (P = .000009).

CONCLUSIONS

IVVM allows direct assessment of circulating HNSCC with the microcirculation and is a powerful model for the study of DM. NO and IL-1 play a role in increasing the arrest of HNSCC in the liver and are important in the generation of DM in patients with HNSCC.

Mouthrinses containing alcohol and oral cancer: revision of epidemiological studies

The strong association between alcohol usage and the development of oral cancer (OC) has been reported in numerous papers. As some mouthrinses contain significant amounts of ethanol, a possible relationship to this pathology has been considered. The purpose of the present paper is to analyze several epidemiological studies which evaluated the association between commercial mouthrinses and the etiology of OC. Although some authors report an association, most of the studies are unclear and sometimes contradictory. The controversial aspects regarding the role of alcohol in OC may also make difficult to find a clear relationship between the use of mouthrinses containing alcohol and OC.

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

CONCLUSION

Our results show that average and poor oral hygiene and inadequate dental status are independent risk factors for oral and oropharyngeal squamous cell carcinoma (OOSCC), irrespective of tobacco and alcohol consumption.

OBJECTIVE

To evaluate a possible relationship between oral cancer, oral hygiene, dental status, oral mucosal lesions and some lifestyle factors in a population-based case-control study.

MATERIAL AND METHODS

Between September 2000 and January 2004, 132/165 (80%) of all incident cases of OOSCC and 320/396 (81%) of the intended eligible matched controls participated in the study. Cases and controls were subjected to an identical oral examination. A standardized protocol specially designed for the study was used.

RESULTS

After adjusting for tobacco and alcohol consumption, average oral hygiene (OR 2.0; 95% CI 1.1-3.6) and poor oral hygiene (OR 5.3; 95% CI 2.5-11.3) emerged as significant risk factors for OOSCC. More than 20 lost teeth (OR 3.4; 95% CI 1.4-8.5), >5 defective teeth (OR 3.1; 95% CI 1.2-8.2) and poorly fitting or defective complete dentures (OR 3.8; 95% CI 1.3-11.4) were significant risk factors. Regular dental check-ups were associated with a decreased risk of OOSCC (OR 0.4; 95% CI 0.2-0.6).

Use of Swedish moist snuff, smoking and alcohol consumption in the aetiology of oral and oropharyngeal squamous cell carcinoma. A population-based case-control study in southern Sweden

CONCLUSIONS

The results of this study confirm that both smoking of tobacco and alcohol consumption are risk factors for oral and oropharyngeal squamous cell carcinoma (OOSCC). The use of moist snuff had no effect on the risk of OOSCC, probably due to the low levels of tobacco-specific N-nitrosamines in Swedish moist snuff.

OBJECTIVE

The aims of this population-based case-control study in southern Sweden were to establish risk estimates for cigarette and alcohol consumption and to evaluate whether Swedish moist snuff is a risk factor for OOSCC.

MATERIAL AND METHODS

Between September 2000 and January 2004, 132/165 consecutive cases (80%) diagnosed with OOSCC and 320/396 matched controls (81%) were investigated. All subjects were interviewed and examined according to a standardized protocol.

RESULTS

Individuals who drank > or =350 g of alcohol/week showed an increased risk of OOSCC (OR 2.6; 95% CI 1.3-5.4). Total lifetime consumption of tobacco for smoking (>250 kg) had a dose-response effect on the risk of OOSCC (OR 4.7; 95% CI 2.4-9.1). We found no increased risk of OOSCC associated with the use of Swedish moist snuff (OR 1.1; 95% CI 0.5-2.5).

Dietary Patterns and Risk of Cancer of the Oral Cavity and Pharynx in Uruguay

From 1995 to 2002, a case-control study on food groups and risk of cancer of the oral cavity and pharynx was conducted in Montevideo, Uruguay. Two hundred thirty cases were frequency-matched to 460 controls on age, residence, and urban/rural status. The study was restricted to men. The relationship between foods and risk of oral and pharyngeal squamous cell carcinoma was examined through: 1) individual food group analysis, 2) factor analysis, and 3) determination of empirical scores. The results were similar. Factor analysis generated 2 patterns, which were labeled as "stew" and "vegetables and fruits." The stew pattern loaded positively on boiled meat, cooked vegetables, potato, and sweet potato. This pattern was directly associated with risk of oral and pharyngeal cancer [odds ratio (OR), 3.75; 95% confidence interval (CI), 1.99-7.06; P value for trend=0.0002]. The vegetables and fruits factor loaded positively on raw vegetables, citrus fruits, other fruits, liver, fish, and desserts. This pattern was inversely associated with risk of oropharyngeal carcinoma (OR, 0.34; 95% CI, 0.18-0.64; P value for trend=0.0008). Joint effects of high intake of risk foods and low intake of protective foods were associated with a risk of 12.0 (95% CI, 4.1-34.6). Our study confirms the important role of dietary factors in oral and pharyngeal cancer risk and suggests that the analysis of dietary patterns is a powerful tool to investigate the links between nutrition and cancer.

Is Periodontitis Associated With Oral Neoplasms?

BACKGROUND

Infections have been suggested in the etiology of oral cancer. This study was carried out to evaluate the effect of periodontal disease on oral soft tissue lesions.

METHODS

A total of 13,798 subjects aged 20 years and older with at least six natural teeth and who participated in the Third National Health and Nutrition Examination Survey (NHANES III) constituted the study population. Severity of periodontal disease was represented by clinical attachment loss (CAL) and was dichotomized as < or =1.5 mm versus >1.5 mm according to its distributions in the NHANES III population. Three separate dependent variables were employed: 1) tumor (non-specific); 2) precancerous lesions; and 3) any oral soft tissue lesion. The independent effect of CAL on those three dependent variables was assessed by weighted multiple logistic regression analyses adjusting for the effects of number of filled teeth, number of decayed teeth, presence of prosthesis, age, gender, race/ethnicity, education, tobacco, alcohol, occupational hazard, and interaction term "tobacco*occupational hazard." Odds ratios (OR) and their 95% confidence intervals (CI) were calculated.

RESULTS

CAL was not related to the presence of any soft tissue lesion (OR = 1.09, 95% CI: 0.91 to 1.31), but was specifically related to the presence of tumor (OR = 4.57, 95% CI: 2.25 to 9.30) and precancerous lesions (OR = 1.55, 95% CI: 1.06 to 2.27).

CONCLUSION

This study suggests associations between periodontal disease and the risk for precancerous lesions and tumors generating a hypothesis about a possible relationship between periodontal disease and oral neoplasms. Prospective or well-designed case-control studies with histologically confirmed incident oral cancer cases are necessary to confirm this relationship.

Is the incidence of oral and pharyngeal cancer increasing in Finland? An epidemiological study of 17 383 cases in 1953-1999

OBJECTIVE

The aim of this study was to describe the occurrence of oral and pharyngeal cancer in Finland over the last half century.

MATERIALS AND METHODS

The study included all lip, oral and pharyngeal cancer cases diagnosed in Finland and reported to the nation-wide Finnish Cancer Registry between 1953 and 1999.

RESULTS

The study comprised 17,383 new cancer cases: 11,666 in males and 5717 in females. Of these, 83% were squamous cell carcinomas. By the end of the study, 1999, the mean age at diagnosis had increased to 63 years for males and 67 for females. The age-adjusted incidence of oral and pharyngeal cancer decreased in males from 12.5 per 10(5) to 8.4 per 10(5) while it increased in females from 3.0 per 10(5) to 3.9 per 10(5). This was because of a decrease in lip cancer incidence in males, while the incidence of tongue, mouth and salivary gland cancers increased in both genders. The annual number of new oral cancer cases increased, however, in both genders.

CONCLUSION

The incidence of lip cancer decreased in males, probably because of a decrease in smoking and in outdoor work. The incidence of intra-oral cancers increased in both genders, possibly because of increased alcohol consumption.

p53-Positive Tumor-Distant Squamous Epithelia of the Head and Neck Reveal Selective Loss of Chromosome 17

OBJECTIVES/HYPOTHESIS

The progression of clinically manifest premalignant lesions in the head and neck region to primary or second primary cancer is characterized by numerical and structural chromosomal aberrations. However, many tumors arise from histologically inconspicuous mucosal sites. The objective was to investigate whether chromosomal aberrations can be detected in tumor-distant mucosa and whether they can help predict the risk of second primary malignancy.

STUDY DESIGN

A retrospective series of 72 clinically healthy, arbitrarily taken mucosal samples from 53 patients with squamous cell carcinoma of the head and neck was studied. A previous analysis of the p53 protein status had revealed both p53-positive and p53-negative samples.

METHODS

The samples were analyzed by fluorescence in situ hybridization (FISH) using centromeric probes specific for the chromosomes 1, 10, 17, and 18.

RESULTS

Tumor-distant mucosa generally showed increased numerical chromosomal aberrations, which consisted mainly of monosomies. In the group of patients with p53-positive epithelia, all aberrations including gains of chromosomes (trisomies, tetrasomies) were more frequent. Monosomy for chromosome 17 was most significantly and selectively enhanced in this group (Wilcoxon Scores [rank sum] test, P =.0002).

CONCLUSION

Detectable chromosomal aberrations occur in clinically healthy epithelia in patients at risk for secondary head and neck cancer. Specifically, unbalanced chromosome 17 monosomy in conjunction with p53 protein overexpression may constitute a valuable biomarker for progressive "field cancerization."

Diet and oral, pharyngeal, and esophageal cancer

Cancers of the upper digestive tract, including those arising in the oral cavity, pharynx, and esophagus, present a significant public health problem worldwide. These cancers are associated with high morbidity and mortality, and identification of protective factors is very important. A number of epidemiological studies have examined the association between vegetables, fruits, carotene, vitamin A, vitamin C, and vitamin E and oral, pharyngeal, and esophageal cancers. The results of 35 epidemiological studies, including one prospective cohort study, one nested case-control study, two randomized controlled trials, nine population-based case-control studies, and 22 hospital-based case-control studies, in addition to in vitro and animal studies, were examined to determine whether the criteria for causal assumption were satisfied for a protective role of these dietary components against development of oral, pharyngeal, and esophageal cancers. There is enough evidence to point to a preventive role of vegetable intake, including green vegetables, cruciferous vegetables, and yellow vegetables, total fruit intake, and citrus fruit intake. Yellow fruits are likely to be protective. Carotene, vitamin C, and vitamin E are protective, most likely in combination with each other and other micronutrients. The role of vitamin A is not clear because of conflicting findings in the studies reviewed.

The utility of tolonium chloride rinse in the diagnosis of recurrent or second primary cancers in patients with prior upper aerodigestive tract cancer

BACKGROUND

The clinical utility of tolonium chloride rinse was compared with unaided visual examination alone in the diagnosis of oral carcinoma in patients previously treated for carcinoma of the upper aerodigestive tract.

METHODS

A total of 668 patients were enrolled in this multicenter study. At each site, an oral clinical visual examination was completed by one investigator followed by tolonium chloride rinse and examination by a second investigator blinded to the examination findings of the first investigator. If a lesion was considered suspicious (urgent biopsy required at the first visit), the lesion was biopsied after tolonium chloride rinsing. Patients with lesions characterized at the first visit as not suspicious (biopsy not urgent) or that stained with tolonium chloride were asked to return for a second visit. At the second visit, any residual lesion or lesions that retained tolonium chloride were biopsied.

RESULTS

A total of 96 biopsies was performed in 81 of the 668 patients (12.1%), of which 30 (31.3%) were diagnosed histologically as carcinoma/carcinoma in situ (CIS) and the remainder as inflammation (31.3%), keratosis (26.6%), dysplasia (21.9%), ulcer (2.1%), other (3.1%), or no abnormality (1.0%). Of the 30 lesions with the diagnosis of carcinoma/CIS, 12 (sensitivity 40.0%) were considered to be clinically suspicious (CS+), whereas 29 (sensitivity 96.7%) retained tolonium chloride (p =.0002). The predictive values of a positive test for clinical examination and tolonium chloride staining were similar (36.4% vs 32.6%; p =.5871), indicating that the greater sensitivity of tolonium chloride was not associated with an excessive number of unnecessary biopsies (false positives).

CONCLUSIONS

Tolonium chloride rinse is more sensitive than clinical examination alone in detecting lesions that might be found on biopsy to be carcinoma or CIS. The increased sensitivity is largely attributed to lesions that stain but were not detected clinically on visual examination.

New revival of an old biomarker: characterisation of buccal cells and determination of genetic damage in the isolated fraction of viable leucocytes

Buccal cells serve as targets to assess oral exposures. We have refined isolation methods to characterise yield, viabilities, types of cells and baseline levels of genetic damage. Buccal cells were isolated from mouthwashes of 27 volunteers. They were characterised microscopically and different methods (using antibody-labelled magnetic beads, filtration and gradient centrifugation) were compared to separate epithelial cells from leucocytes. Viability of cells, DNA damage, and activity of glutathione S-transferase (GST) were measured with dye exclusion, microgelelectrophoresis, and biochemically. Mouthwashes contained approximately equal amounts of epithelial cells and leucocytes with detectable GST-activities. Repetitive determinations with mouthwashes from four individuals yielded per sample (3.5+/-1.4)x10(6) epithelial cells and (4.7+/-3.9)x10(6) leucocytes with viabilities of 8 and 94%, respectively. Epithelial cells could not be isolated using antibody-labelled beads, but cell separation with the leukocyte-specific antibody CD45 succeeded, yielding 37% leucocytes with a purity of 95% and viability of 65%. Filtering the mouthwash through a 10 microm filter yielded 57% leucocytes, with 86% purity and 94% viability. When using density gradient centrifugation as the separation method, the recovery of leucocytes was low (22%), but good results were scored for purity (95%) and cell viability (88%). This method was used to isolate leucocytes, which were then subjected to a micro-scale comet assay-modification. It was found that buccal leucocytes obtained from smokers had more DNA damage than cells from non-smokers. In conclusion, suspensions of buccal cells consist in approximately equal parts of epithelial cells and leucocytes. Only leucocytes are sufficiently viable for measuring parameters of cytotoxicity and genotoxicity or for studying modulation of gene expression. The cells are useful targets of non-invasive biomarkers, which could be incorporated as tools in many types of intervention studies.

Outcomes of oral squamous cell carcinoma in Taiwan after surgical therapy: factors affecting survival

PURPOSE

The study goal was to determine which clinical features correlated with 5-year survival in patients surgically treated for oral squamous cell carcinoma (OSCC) in Taiwan.

PATIENTS AND METHODS

The records of 378 OSCC patients surgically treated with or without chemotherapy and radiotherapy were reviewed retrospectively. Their 5-year survival in relation to age, gender, tumor site, lymph node involvement, presence of distant metastasis, staging, differentiation, and risk factors, including betel quid (BQ) chewing, cigarette smoking, and alcohol consumption, was analyzed.

RESULTS

The majority of the patients were men (male-to-female ratio, 5.87:1) with the mean age of 57.1 +/-11.7 years. Tumors occurred mainly at the buccal mucosa (BM) (100 of 378, 26.5%), gingiva (105 of 378, 27.8%), and tongue (103 of 378, 27.2%). Neck nodal metastasis occurred frequently at the floor of the mouth (in >60% of cases), followed by the gingiva (45.7%), buccal mucosa (34%), and tongue (20.4%), whereas early distant metastasis was rare (5.3%). There were 104 (27.5%) stage 1, 96 (25.4%) stage 2, 98 (25.9%) stage 3, and 80 (21.2%) stage 4 patients. OSCC at the BM and gingiva was most (and at the tongue least) associated with risk factors of BQ use and smoking. The 5-year survival was 75%, 65.6%, 49%, and 30% for patients with stage I, II, III, and IV, respectively. The size, nodal involvement, distant metastasis, staging, differentiation, and BQ use significantly affected the survival (P <.05, Kaplan-Meier analysis). BQ use also correlated most significantly with the younger age of occurrence of OSCC patients.

CONCLUSIONS

Our data suggest that early treatment is the key to increasing the survival of OSCC patients. Periodic screening of high-risk populations for OSCC represents an urgent need in Taiwan.

Tooth loss, pancreatic cancer, and Helicobacter pylori

BACKGROUND

Poor dental health has been associated with increased risks of oral, esophageal, and gastric cancer and may also be associated with pancreatic cancer. In addition, Helicobacter pylori has been found in dental plaque and has been associated with periodontal disease and pancreatic cancer.

OBJECTIVE

The objective was to investigate prospectively the relation between dentition history and pancreatic cancer in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort in Finland and the association between dentition history and H. pylori seropositivity in a cross-sectional sample of subjects without cancer (n = 475) from the same cohort.

DESIGN

Of the 29,104 male smokers aged 50-69 y in the cohort for whom there were complete data, 174 developed pancreatic cancer from 1985 to 1997. Cox proportional hazard models were used to estimate age-, smoking-, education-, urban living-, and height-adjusted hazard ratios and 95% CIs for pancreatic cancer, and logistic regression models were used to estimate age- and education-adjusted odds ratios for H. pylori carriage.

RESULTS

Tooth loss was positively associated with pancreatic cancer (edentulous compared with missing 0-10 teeth: hazard ratio = 1.63; 95% CI: 1.09, 2.46; P for trend = 0.02) but was not significantly associated with H. pylori seropositivity (edentulous compared with missing 0-10 teeth: odds ratio = 1.30; 95% CI: 0.73, 2.32; P for trend = 0.37).

CONCLUSION

Additional studies are needed to evaluate the association between tooth loss and pancreatic cancer, as well as cancers at other gastrointestinal sites, particularly with respect to possible biological mechanisms.

Oral cancer in Southern India: the influence of body size, diet, infections and sexual practices

Between 1996 and 1999, we carried out a study in Southern India on risk factors for oral cancer. The study included 591 incident cases of cancer of the oral cavity (282 women) and 582 hospital controls (290 women). Height was unrelated to oral cancer risk. Body mass index (weight in kilograms/height in metres squared) was inversely associated with risk (P for trend<0.001). Paan chewers with low BMI were at particularly high risk. Risk was increased among subjects consuming meat (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.00-2.37), ham and salami (OR 4.40, 95% CI 2.88-6.71) two or more times per week. Frequent consumption of fish, eggs, raw green vegetables, cruciferous vegetables, carrots, pulses, apples or pears, citrus fruit, and overall consumption of vegetables and fruit decreased oral cancer risk (P for trend for each of these items less than or equal to 0.001). The risk associated with low consumption of vegetables was higher among smokers than among non-smokers. Men, but not women, who practised oral sex had an increased oral cancer risk (OR 3.14, 95% CI 1.15-8.63). Women with more than one sexual partner during life were at increased oral cancer risk (OR 9.93, 95% CI 1.57-62.9).

Smoking, alcohol, diet, dentition and sexual practices in the epidemiology of oral cancer in Poland

The effect of smoking, drinking, diet, dental care and sexual habits on the risk of oral and pharyngeal cancer was investigated in a case-control study conducted in Warsaw, Poland. The study comprised 122 patients (including 44 females) aged 23-80 years with histologically confirmed cancer of oral cavity and pharynx. Controls were 124 subjects (including 52 females) admitted to the hospital for different non-neoplastic conditions unrelated to tobacco and alcohol consumption, with frequency matched to cases by age and sex. Smoking and drinking were strongly associated with an increased risk of oral cancer. Among consumers of both products, risks of oral cancer tended to combine in a multiplicative fashion and were increased more than 14-fold among those who consumed more than 15 cigarettes and seven or more drinks per day. Cessation of smoking was associated with reduced risk of this cancer. The risks varied by type of cigarettes smoked, being lower among those consuming filtered cigarettes only (OR = 1.6) than nonfilter (OR = 6.5) or mixed (OR = 4.2) cigarettes. High fruit intake was associated with significantly decreased risk (OR = 0.4) with the strongest significant inverse association found for fruit juices and citrus fruits ( < 0.01). After adjustment for tobacco smoking and alcohol drinking, poor dentition as evidenced by missing teeth, frequency of dental check-ups and frequency of teeth brushing emerged as a strong risk factor. Number of missing teeth and frequency of dental check-ups and frequency of tooth brushing showed increased ORs of 9.8, 11.9 and 3.2, respectively. Denture wearing did not affect oral cancer risk. No differences were detected in sexual practices (including oral sex and intercourse with prostitutes). In terms of attributable risk, smoking accounted for 57% of oral cancer cases in Poland, alcohol for 31% and low fruit intake for 12%. Attributable risks for low frequency of tooth brushing and dental check-ups were 56% and 47%, respectively. In conclusion, smoking and drinking cessation and increase of fresh fruit intake are likely to be effective preventive measures against oral cancer. These findings indicate also that poor oral hygiene may be an independent risk factor.

Oral and oropharyngeal cancer in Spain: influence of dietary patterns

Cancer of the oral cavity and oropharynx is a major public health problem in Spain. Tobacco and alcohol have been identified as the two major risk factors for oral cancer in most western populations. Other risk factors include diets low in fruits and vegetables, but the impact of dietary habits on the risk of these cancers has never been assessed in Spain. The objective of this study was to elucidate the role of dietary habits in oral and oropharyngeal cancer, a multicentric case-control study was conducted in three areas of Spain (Barcelona, Granada and Sevilla) between 1996 and 1999. Cases were 375 patients (71 women), with incident, histologically confirmed cancer of the oral cavity or oropharynx, and controls were 375 subjects (71 women) admitted to hospitals for conditions unrelated to smoking or alcohol drinking. Data were analysed using multivariate logistic regression procedures. After allowance for education, tobacco and alcohol use, a significant inverse association with the risk of oral and oropharyngeal cancer was found for total consumption of total green vegetables (OR 0.54, 95% CI = 0.34-0.87) and total fruit (OR 0.52, 95% CI = 0.34-0.79) with significant trends in risk. We found that the protective effect of each of these food items was consistently larger among current smokers and among heavy alcohol drinkers, following a multiplicative effect model. In conclusion, this study provides further support to the beneficial effect of high intake of vegetables and fruits on the risk of developing cancers of the oral cavity and oropharynx in Spain, particularly among current smokers and heavy alcohol drinkers.