Prevalence of oral cancer and pre-cancer and associated risk factors among tea estate workers in the central Sri Lanka

BACKGROUND: To screen for oral cancer or not is being debated, but for high-risk populations with minimal access to regular dental care systematic oral examinations could provide some benefit. METHODS: We undertook oral mucosal examinations of labourers employed in tea estate plantations in Sri Lanka. In a two-stage screening procedure, first by estate medical officers and then by visiting specialists, we examined 12 716 persons at their workplaces achieving a coverage of one-sixth of the total workforce. RESULTS: Fourteen oral cancers and 848 subjects with oral pre-cancer (6.7%) were detected giving population prevalences of 46.1 per 1000 for leukoplakia and 16.4 per 1000 for oral submucous fibrosis. Among subjects with any oral mucosal disorder (n = 1159) proportions of current users of betel quid, smokers and alcohol use was recorded at 92%, 31% and 61% respectively. The synergistic effect of these three risk habits on the development of oral leukoplakia was evident in mixed habit groups. CONCLUSIONS: The prevalence of oral pre-cancer in tea estate labourers was higher than estimates reported in previous studies. In the absence of state-sponsored preventive activities, it is necessary to improve the capacity of individual health practitioners and small medical centres to participate in oral health promotion and oral cancer/pre-cancer screening.     

The permeability of oral leukoplakia

The significant increase in oral cancer mortality necessitates further research on the mechanisms of tumorigenesis. It was the aim of this study to compare the permeability, lipid composition and histopathological characteristics of oral leukoplakia with non-lesional specimens of the same region in 30 cases as well as 11 specimens originating from healthy control buccal mucosa. The permeability (Kp) of tissue biopsies to tritiated nitrosonornicotine was determined in a continuous through-flow perfusion system, lipids were extracted and identified by thin-layer chromatography, and thickness of epithelium and keratin layer assessed by histopathological methods. Results of the measurements showed that the permeability to the tobacco carcinogen, nitrosonornicotine for leukoplakic tissue was higher than for normal control buccal specimens. Non-lesional areas of buccal mucosa, adjacent to leukoplakias, showed hyperplasia and significantly higher permeability values than both leukoplakic and normal buccal control mucosa. The lipid content of the non-lesional sites was intermediate between the increased values of the leukoplakic lesion and of normal control mucosa. The data strongly suggest that the presence of tobacco in the oral cavity may bring about generalized changes even in regions that do not show leukoplakia.     

Epidemiologic study of the association between alcohol habits and oral leukoplakia

In a house-to-house survey in Ernakulam district, Kerala State, 10914 individuals were interviewed for their tobacco and alcohol habits and examined for the presence of oral leukoplakia. Very few females (1.6%) were found to be alcohol users and they were excluded from further analysis. Among 7604 males, 30.4% used alcohol regularly, 25.4% occasionally and 44.2% were non-users. The prevalence of leukoplakia was significantly higher among regular (5.7%) and occasional (3.9%) users than among non-users (2.9%) of alcohol. Alcohol usage was found to be related to age as well as tobacco habits. The prevalence of leukoplakia was higher among alcohol users in each age-group as well as in each tobacco habit category. After age-adjustment the difference between alcohol users and non-users, although reduced, remained significant. For most tobacco habit categories the trend remained similar after age-adjustment except for the mixed habits group, for which there was a reversal of the trend. The alcohol habit may, perhaps, produce discernible effects only in association with other 'weak' etiological risk factors, such as a single tobacco habit of smoking or chewing rather than a 'strong' etiologic factor such as the mixed habits of chewing and smoking.     

The role of ascorbic acid in oral cancer and carcinogenesis

L-ascorbic acid is an essential dietary vitamin in humans, primates and certain mammals and is endogenously syn-thesised in some species. Epidemiological and ecological studies have shown that L-ascorbic acid has a protective effect against cancer, in particular non-hormone-dependent malignancies, such as oropharyngeal neoplasms. Experimental in vivo and in vitro studies, however, have yielded more controversial results, suggesting that the effects of L-ascorbic acid are dose- and perhaps, time-dependent with different effects depending on the species or organ studied. An update of the epidemiological and experimental evidence linking L-ascorbic acid to oral cancer and carcinogenesis is discussed together with a brief review of the possible mechanisms of action of L-ascorbic acid.     

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口腔黏膜白斑(oral leukoplakia)是一种临床表现为口腔黏膜出现白色增生斑块,病理学表现以上皮过角化为特点的疾病。世界卫生组织已将其列为癌前病变,是需高度监控的口腔疾病。     

ALDH1在OLP和LK组织中的表达及其意义

目的：通过检测干细胞标记物ALDH1在口腔扁平苔藓（OLP）和白斑（LK）中的表达水平,评价其与癌变的关系。方法：采用免疫组织化学SP法检测ALDH1在10例正常口腔黏膜,30例OLP,60例LK,10例口腔鳞癌（OS－CC）中表达水平;再检测ALDH1在30例癌变与30例未癌变LK中的表达差异。结果：ALDH1在正常口腔黏膜中不表达,在OLP、LK和OSCC中的表达率分别为26．7％,63．3％和90．0％（P＜0．05）;ALDH1在未癌变和癌变LK中的表达率分别是43．3％和83．3％（P＜0．01）。结论：ALDH1与口腔黏膜恶性潜能程度相关,可能是预测癌变的分子标记物。     

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目的研究鸟氨酸脱羧酶（ODC）与口腔白斑的发生、发展乃至癌变潜能的关系。方法选取2009—2010年大连医科大学附属第一医院口腔科收治且经病理确诊的口腔白斑患者22例,以其病变黏膜组织为研究对象,同时以11例正常口腔黏膜、22例口腔扁平苔藓组织和22例口腔鳞癌组织为对照。采用免疫组化法检测ODC在各种组织中的表达,并对阳性率进行比较分析。结果在口腔正常黏膜、扁平苔藓、白斑和鳞癌组织中ODC的阳性率依次增加;ODC在口腔扁平苔藓中的阳性率高于正常黏膜,但差异无统计学意义（P〉0.05）,ODC在口腔白斑中的阳性率与正常黏膜和扁平苔藓的差异均有统计学意义（P〈0.05）,口腔鳞癌组织中ODC的阳性率显著高于其余组（P〈0.05）。结论 ODC表达程度可用于判断口腔白斑的恶变倾向及口腔鳞癌的恶性程度。     

Associations between clinical and histopathological characteristics in oral leukoplakia

Objectives

To identify possible associations between patients’ demographics and habits and the clinical aspects and histopathological characteristics of oral leukoplakia (OL) at patients’ first visit.

Method

A total of 140 consecutive patients with OL at a single institute between 1997 and 2019. All biopsies were microscopically examined for classic dysplasia (CD) (WHO definition oral epithelial dysplasia) and differentiated dysplasia (DD) known from differentiated vulvar intraepithelial neoplasia. Clinical characteristics were correlated to histopathological diagnosis and odds ratios (OR) were calculated.

Results

A total of 96 females and 44 males, mean age 58 years, were presented. OLs were found mainly on the tongue (41%) and floor of mouth (FOM) (18%). Homogeneous OLs (58%) were associated with smoking, FOM and size <2cm and non-homogeneous OLs (42%) with non-smokers. No dysplasia was present in 40% and any dysplasia (AD) in 60%. Tongue OLs were correlated with AD (OR:6.0) and CD (OR:5.7). FOM OLs were correlated with CD (OR:4.5). DD was correlated with non-homogeneous OLs (OR:2.6).

Conclusions

CD was most frequently observed in tongue and FOM OLs, while DD was associated with non-homogeneous OLs. In this series of patients, there was no consistent reliable association between the clinical and histopathological features and clinical characteristics can therefore not substitute microscopic examination of biopsies.     

Midkine expression in oral squamous cell carcinoma and leukoplakia

J Oral Pathol Med (2012) 41 : 21–26 Background: Midkine (MK), a 13‐kDa heparin‐binding growth factor, is overexpressed in various human cancers. However, its role in the development and progression of oral cavity squamous cell carcinoma (OCSCC) is still unclear. Thus, the aim of this study was to evaluate the expression of MK in samples of OCSCC, leukoplakia, and healthy oral mucosa (control). Methods: Surgically excised specimens from patients with primary OCSCC (n = 28) were immunostained for MK, Ki‐67, PCNA, p53, bcl‐2, Bax, and CD31. Besides this, MK expression was also investigated in leukoplakia and normal oral mucosa. The relationship of MK⁺ cells with clinical parameters (tumor location, tumor size, lymph node metastasis, and survival) and microscopic parameters (WHO histological grading, intensity of inflammation, proliferation index, apoptosis, and angiogenesis) was also evaluated. Results: The results showed that MK expression was increased in OCSCC in relation to leukoplakia and normal mucosa. Furthermore, MK expression was increased in late‐stage tumors (T3/T4) compared with early‐stage lesions (T1/T2). MK‐positive lesions also showed increased expression of the anti‐apoptotic protein bcl‐2. Conclusion: OCSCC, particularly late‐stage tumors, exhibits increased MK expression, which may be involved in tumor progression via upregulation of anti‐apoptotic genes, as shown by the augmented bcl‐2 positivity in MK‐positive tumors.     

Occurrence of oral leukoplakia and lichen planus in diabetes mellitus

The occurrence of oral leukoplakia and lichen planus in 1600 patients with diabetes mellitus (815 type 1: insulin-dependent, 761 type 2: non-insulin-dependent)-under care at the International Medicine Department-was studied. Precancerous lesions and conditions were diagnosed and grouped according to internationally accepted criteria. The prevalence of oral leukoplakia in diabetic patients was 6.2%, as compared to 2.2% in the healthy controls, that of oral lichen was 1.0% in the test-, and 0.0% in the control group. Leukoplakia and lichen both showed the highest occurrence in the second year of established diabetes, and their prevalence was higher among insulin-treated diabetics. Smokers were more often affected, by both kind of lesions, oral lichen showed a more frequent association with candidiasis. The prevalence of oral leukoplakia and lichen in diabetes mellitus patients was higher, than average ratios in population samples from the same country.     

乙醇与口腔癌临床流行病学的研究进展

口腔癌是人类最常见的恶性肿瘤之一,其中2/3的患者来自发展中国家.虽然治疗方法在进步,但口腔癌的预后较差,5年生存率仍低于50%.研究口腔癌的危险因素十分重要,明确危险因素可制定有效的预防措施,以减少口腔癌的发生.乙醇是导致口腔癌的危险因素之一,流行病学调查提示乙醇可导致口腔癌,但此结论在动物试验中尚未被证实.研究乙醇因素与口腔癌的关系需要同时分析饮酒量、酒的类型、饮酒习惯以及乙醇对不同性别的影响和烟酒的联合作用.饮酒和吸烟与口腔癌的发生密切相关,但同时吸烟和饮酒者因乙醇致癌的具体机制难以明确,然而戒除烟酒却是获得口腔癌有效预防的关键因素.     

Incidence rates for oral leukoplakia and lichen planus in a Japanese population

BACKGROUND: Data on the incidence rates of potentially malignant diseases of the oral cavity in different populations is meagre. This is the first study to report on the age-specific incidence of oral leukoplakia and oral lichen planus from an industrialized country. METHODS: Annual screening for oral cancer and pre-cancer was undertaken in Municipal Health Centres in Tokoname city, Japan from 1995 to 1998. A total of 9536 volunteers aged 40-95 years participated in this programme. A cohort of 6340 (67%) subjects attended annual mouth examinations following a negative screen result at entry, allowing 13 072 person-years of observations. Some associated risk factors (tobacco and alcohol misuse) and health-related variables were also evaluated. RESULTS: Over a 4-year follow-up period, 18 new oral leukoplakias (all homogenous; 11 idiopathic and seven tobacco-associated) and 24 oral lichen planus (22 reticular, one erythematous and one ulcerative) were detected at screening and confirmed by re-examination at specialist units. The age-adjusted incidence rate for leukoplakia was 409.2 (95% CI: 90.6-727.9) in male and 70.0 (95% CI: 17.9-121.8) in female per 100,000 person-years observations. For lichen planus, the corresponding rates were 59.7 (95% CI: 7.4-112.1) and 188.0 (95% CI: 96.0-280.1). The age-adjusted incidence rate for tobacco-associated leukoplakia in males was almost 12 times compared with female (560.3 vs. 45.2 per 100,000). Age-specific incidence rates for oral leukoplakia varied by age groups. New oral leukoplakias were more prevalent on gingival/alveolar ridge (33.3%) than in other oral sites, and lichen planus at buccal site (33.3%). Prevalence of smoking habits among those positive for leukoplakia (38.9%) was higher compared with the screen-negatives (26.4%) but these differences did not reach statistical significance (P = 0.232). Regular drinking was not related to occurrence of either oral leukoplakia or oral lichen planus. In cases with diabetes mellitus, relative risk for oral lichen planus adjusted by logistic regression was 6.4 (95% CI: 2.4-17.6), suggesting an association. CONCLUSIONS: The reported incidence rates for oral leukoplakia in this Japanese population are somewhat higher to those reported from India, the risk habits of the two groups being markedly different. The reported rates for oral leukoplakia and lichen planus allow estimation of service needs in specialist oral medicine clinics and for the training of primary care dentists. A high incidence of idiopathic leukoplakia found in this study raises challenges to the strategy of screening high-risk populations aimed at conserving resources.     

The expression of the Epstein-Barr virus nuclear antigen (EBNA-I) in oral hairy leukoplakia

OBJECTIVE: Oral hairy leukoplakia (OHL) is characterised by the presence of a replicative Epstein-Barr virus (EBV) in the superficial layers of the epithelium. There is some doubt, however, whether this reflects activation of a latent infection of the basal epithelial cells. EBV latency is associated with the expression of the viral gene product EBNA-I and the aim of this study was to investigate EBNA-I expression in OHL. METHODS: 22 biopsies of clinically suspicious OHL and three cases of normal mucosa were available as fresh frozen or paraffin embedded material. EBNA-I was detected immunocytochemically using a rat monoclonal antibody (IH4-I) following microwave irradiation. Lytic EBV infection was confirmed by the identification of the BZLF-I protein. RESULTS: 16 of the 22 cases displayed focal replicative EBV meeting the criteria for OHL, and in 13 of these, EBNA-I expression was restricted to the nuclei of epithelial cells in the upper layers of the epithelium. EBNA-I expression was absent from the basal cells in all cases and in the nine BZLF-I negative mucosal biopsies. CONCLUSION: These findings suggest that lytic EBV infection in OHL is not the result of activation of a latent infection of basal cells and suggests a role for EBNA-I, not only in latent EBV infection, but also in virus replication.     

Prevalence of oral leukoplakia in Havana City, Cuba

Abstract A survey related to the detection of precancerous lesions of the oral cavity has been done in Cuba for the first time. The sample comprised 749 randomly selected workers from Havana City Province, taking into account the censal records of the Cuban population up to 1979. Prevalence of lesions and their relation to age, sex and predisposing factors, such as smoking, alcohol habits and mechanical trauma were studied. 4.4% of leukoplakia and preleukoplakia considered together and 2.1 % leukoplakia alone, and two cases of oral lichen planus and leukokeratosis nicotina palati (0.1 % of each) were found. The former lesions were more frequently encountered in people above 50 years old, specially in males and specifically among those who had smoked for more than 10 years. Sites of location most frequently encountered were the buccal mucosa and the labial commissures.     

Increased salivary lipid peroxidation in human subjects with oral lichen planus

Abstract: Background: Oral lichen planus (OLP) is a chronic inflammatory mucosal disease of unknown aetiology. Recently, increased oxidative stress has been implicated in the pathogenesis of various diseases. The aim of this study was to evaluate the total antioxidant capacity (TAC) and lipid peroxidation level, in the saliva of patients with OLP. Method: Thirty patients with OLP (15 men, 15 women; mean age 44.0, SD ± 11.4 years) and 30 control subjects (16 men, 14 women; aged 23–67 years), matched for age and gender, were enrolled in this case and control study. This study was conducted at the Clinic of Oral Medicine of Tehran University of Medical Sciences in 2007. The unstimulated whole saliva malondialdehyde (MDA), as an indicator of lipid peroxidation and TAC levels were assayed by thiobarbituric acid and ferric reducing antioxidant potential (FRAP), respectively, in both groups. Results: Mean levels of saliva MDA, but not TAC, in patients with OLP was significantly higher than those of the control group. Conclusion: We conclude that OLP patients have more cellular lipid peroxidation than healthy subjects.