At a workshop coordinated by the WHO Collaborating Centre for Oral Cancer and Precancer in the UK issues related to terminology, definitions and classification of oral precancer were discussed by an expert group The consensus views of the Working Group are presented here The term, 'potentially malignant disorders', was recommended to refer to precancer as it conveys that not all disorders described under this term may transform into cancer Critically evaluating all definitions proposed so far for oral leukoplakia, the Working Group agreed that the term leukoplakia should be used to recognize 'white plaques of questionable risk having excluded (other) known diseases or disorders that carry no increased risk for cancer' An outline was proposed for diagnosing oral leukoplakia that will prevent other oral white disorders being misclassified as leukoplakia The Working Group discussed the caveats involved in the current use of terminology and classification of oral potentially malignant disorders, deficiencies of these complex systems, and how they have evolved over the past several decades The terminology presented in this report reflects our best understanding of multi-step carcinogenesis in the oral mucosa, and aspires to engender consistency in use

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1600-0714.2007.00582.x

Nomenclature and classification of potentially malignant disorders of the oral mucosa

In the United States, cancers of the oral cavity and oropharynx represent approximately three percent of all malignancies in men and two percent of all malignancies in women. The American Cancer Society estimates that 28,900 new cases of oral cancer will be diagnosed in 2002, and nearly 7,400 people will die from this disease. Over 90 percent of these tumors are squamous cell carcinomas, which arise from the oral mucosal lining. In spite of the ready accessibility of the oral cavity to direct examination, these malignancies still are often not detected until a late stage, and the survival rate for oral cancer has remained essentially unchanged over the past three decades. The purpose of this article is to review the clinical features of oral cancer and premalignant oral lesions, with an emphasis on early detection.

/pdf/oral-cancer-and-precancerous-lesions-1ae8yh9kz7.pdf

Oral cancer and precancerous lesions.

Objective: The purpose of this review is to provide guidance on the development, validation and use of food-frequency questionnaires (FFQs) for different study designs. It does not include any recommendations about the most appropriate method for dietary assessment (e.g. food-frequency questionnaire versus weighed record). Methods: A comprehensive search of electronic databases was carried out for publications from 1980 to 1999. Findings from the review were then commented upon and added to by a group of international experts. Results: Recommendations have been developed to aid in the design, validation and use of FFQs. Specific details of each of these areas are discussed in the text. Conclusions: FFQs are being used in a variety of ways and different study designs. There is no gold standard for directly assessing the validity of FFQs. Nevertheless, the outcome of this review should help those wishing to develop or adapt an FFQ to validate it for its intended use.

/pdf/development-validation-and-utilisation-of-food-frequency-148skc2jci.pdf

Development, validation and utilisation of food-frequency questionnaires - a review.

This 11th edition of the book Modern Nutrition in Health and Disease, featuring the work of more than 190 expert authors and divided into five parts, fully explains and encapsulates the fundamentals of nutrition and its role in contemporary society, from mastering the basic science of nutrient metabolism and function to applying nutritional concepts to combat human disease. Part I comprehensively covers specific dietary components, including major dietary constituents, minerals, vitamins and other Other CABI sites 

Modern Nutrition in Health and Disease

Two hundred fifty-seven patients with oral leukoplakia were studied and followed for an average period of 7.2 years. All lesions were more than one cm in size and had been present and observed for a minimum of 6 months. Of the initial biopsies, 235 revealed a benign hyperkeratosis and 22 others contained some degree of epithelial dysplasia. Seventy-three percent of the patients used tobacco, with cigarette usage being the predominant form. Forty-five patients (17.5%) subsequently developed squamous carcinomas in the hyperkeratotic epithelial site in an average time of 8.1 years. Eight of these malignant transformations came from patients who originally had epithelial dysplasia. High risks for malignant transformation also included non-smoking patients, the clinical presence of erythroplasia (erythroleukoplakia), and a clinical verrucous-papillary hyperkeratotic pattern. Duration of the leukoplakia progressively increased the total number of malignant transformations, with the largest rate occurring in the second year. This study confirms that oral leukoplakia is a precancerous lesion and that certain characteristics indicate greater risks and warrant consideration of more aggressive management.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1097-0142%2819840201%2953%3A3%3C563%3A%3AAID-CNCR2820530332%3E3.0.CO%3B2-F

Oral leukoplakia and malignant transformation. A follow-up study of 257 patients.

Incidence rates of oral cancer and natural history of oral precancerous lesions in a 10-year follow-up study of Indian villagers.

Sixty-six patients with oral submucous fibrosis were followed-up for a period of 17 yr (median observation 10 yr) in Ernakulam District, Kerala, India. Oral cancer developed in five (7.6%) patients. The malignant transformation rate in the same sample was 4.5% over a 15-yr observation period (median 8 yr). These findings impart a high degree of malignant potential to this condition.

Malignant transformation rate in oral submucous fibrosis over a 17-year period.

Oral submucous fibrosis (OSF) is a high risk precancerous condition, predominantly affecting Indians. Consumption of chilli was hypothesized as an etiologic factor on the basis of ecological observations and a solitary animal experimental study. Subsequent epidemiologic studies that included case-series reports, large cross-sectional surveys, case-control studies, cohort and intervention studies have identified areca nut as the major etiologic agent. Tissue-culture studies involving human fibroblasts, areca nut extracts and areca nut alkaloids supported this etiologic hypothesis by showing fibroblastic proliferation and increased collagen formation. Currently, the role of genetic susceptibility and that of autoimmunity are receiving attention. The influence of nutritional factors, if any, remains unclear.

Etiology of oral submucous fibrosis with special reference to the role of areca nut chewing

A case-control study to elucidate the etiology of oral submucous fibrosis was conducted in Bhavnagar, Gujarat. Sixty consecutively arriving oral submucous fibrosis patients at a dental clinic were selected as cases. An equal number of controls matched for age, sex, religion and socioeconomic status were selected from individuals who did not exhibit any oral mucosal lesion or condition. Among cases, 98% chewed areca nut regularly in one form or the other whereas among controls 35% chewed areca nut, giving an overall relative risk of 109.6. Areca nut chewing was practiced most commonly in the form of mawa: a mixture containing mainly areca nut (over 90% by weight), some tobacco, and a few drops of lime. Mawa chewers and those who chewed mawa along with other chewing habits showed very high relative risks. The relative risks increased with increase in the frequency as well as the duration of chewing habits. In a bivariate analysis the effect of frequency and duration of chewing appeared to be multiplicative. The present findings confirm areca nut as the most important etiologic factor in oral submucous fibrosis.

A case-control study of oral submucous fibrosis with special reference to the etiologic role of areca nut.

An evaluation of the malignant potential of submucous fibrosis, based on observations of 89 patients with the disease in Ernakulam District, Kerala, India was done. Out of the 89 patients, 12 were referred patients and 77 were diagnosed in population based studies. At the time of first examination oral cancer was found to be coexistent in nine (10%) cases. For 66 patients follow-up observations ranging from 4 to 15 yr (median 8 yr) were available. During this period malignant transformation was observed in three patients (4.5%). Considering malignant transformation and coexistence together, oral cancer was observed in 13% of the present material. Leukoplakia was found in 26% of the patients with submucous fibrosis. Out of 42 submucous fibrosis patients biopsied, 12% showed squamous cell carcinoma, 26% epithelial dysplasia, and 76% atrophic epithelium. These findings reinforced the hypothesis that submucous fibrosis is a precancerous condition.

R. B. Bhonsle

Papers

Incidence rates of oral cancer and natural history of oral precancerous lesions in a 10-year follow-up study of Indian villagers.

Malignant transformation rate in oral submucous fibrosis over a 17-year period.

Etiology of oral submucous fibrosis with special reference to the role of areca nut chewing

A case-control study of oral submucous fibrosis with special reference to the etiologic role of areca nut.

Oral submucous fibrosis as a precancerous condition.