Risk factors for multiple oral premalignant lesions

Oral leukoplakia, oral submucous fibrosis and erythroplakia are 3 major types of oral premalignant lesions. Multiple oral premalignant lesions may possibly develop due to field cancerization, where carcinogenic exposures can cause simultaneous genetic defects to the upper aerodigestive tract epithelium, putting the epithelium at high risk for development of premalignant lesions at different stages of carcinogenesis. There have been no epidemiological studies on risk or protective factors of the disease. A case-control study was conducted with data from the baseline screening of a randomized oral cancer screening trial in Kerala, India. A total of 115 subjects with multiple oral premalignant lesions (8-10% of oral premalignant lesions in our case series) were included: 64 subjects with oral leukoplakia and oral submucous fibrosis, 19 subjects with oral leukoplakia and erythroplakia, 22 subjects with oral submucous fibrosis and erythroplakia and 10 subjects with all 3 lesions. Individuals without oral lesions were considered controls (n=47,773). The odds ratio (OR) for ever tobacco chewers was 37.8 (95% confidence interval (CI)=16.2-88.1) when adjusted for age, sex, education, BMI, smoking, drinking and fruit/vegetable intake. Dose-response relationships were seen for the frequency (p<0.0001) and duration of tobacco chewing (p<0.0001) with the risk of multiple oral premalignant lesions. Whereas alcohol drinking may possibly be a risk factor for multiple oral premalignant lesions, smoking was not associated with the risk of multiple oral premalignant lesions (OR=0.9, 95%CI=0.5-1.7). The results suggest that tobacco chewing was the most important risk factor for multiple oral premalignant lesions and may be a major source of field cancerization on the oral epithelium in the Indian population.     

The use of artificial dermis for surgical defects in the treatment of oral premalignant lesions

BACKGROUND: This study investigated the application of an artificial dermis as a substitute for split-thickness skin graft in an oral mucosal defect after excision of a premalignant lesion. METHODS: We examined a total of 125 sites repaired with artificial dermis in 84 patients. Forty-one of 84 patients had two different defects and 43 had a single defect. Of 84 patients, there were 52 oral leukoplakia and 32 oral submucous fibrosis. RESULTS: Most patients chewed betel nuts (97.6%). Most of the premalignant lesions were located in the buccal mucosa (94%). The overall success rate was 100% without any or partial graft loss. The minor wound oozing occurred in three grafts (2.4%). No patient had an immunologic reaction or experienced with significant pain. CONCLUSIONS: Therefore, an artificial dermis may be an alterative to a split-thickness skin graft for patients with oral mucosal defects after removal of premalignant lesions.     

Oral leukoplakia: a Clinicopathological review

Leukoplakia is the most common premalignant or potentially malignant lesion of the oral mucosa. It seems preferable to use the term leukoplakia as a clinical term only. When a biopsy is taken, the term leukoplakia should be replaced by the diagnosis obtained histologically. The annual percentage of malignant transformation varies in different parts of the world, probably as a result of differences in tobacco and dietary habits. Although epithelial dysplasia is an important predictive factor of malignant transformation, it should be realized that not all dysplastic lesions will become malignant. On the other hand non-dysplastic lesions may become malignant as well. In some parts of the world the tongue and the floor of the mouth can be considered to be high-risk sites with regard to malignant transformation of leukoplakia, while this does not have to be the case in other parts of the world. The cessation of tobacco habits, being the most common known aetiological factor of oral leukoplakia, has been shown to be an effective measure with regard to the incidence of leukoplakia and, thereby, the incidence of oral cancer as well. Screening for oral precancer may be indicated in individuals at risk.     

头颈部肿瘤化疗引起口腔黏膜炎的危险因素分析

目的:探讨影响头颈部肿瘤化疗引起口腔黏膜炎的危险因素。方法:研究对象为2011年5月-2013年6月我市三甲医院315例头颈部接受化疗的肿瘤患者,分析引起头颈部肿瘤化疗患者口腔黏膜炎症的影响因素。结果:随着患者年龄的增大,口腔黏膜炎的发病率有逐渐升高的趋势,有吸烟史的患者以及有义齿的患者口腔黏膜的发病率较高,性别对于口腔黏膜炎症的发病率没有影响;口腔pH、白细胞数与患者口腔黏膜炎症的发病率没有显著性的关系（P＜0.05）,含5-FU、口腔疾患、预防漱口等与患者口腔黏膜炎症的发病率有显著性的关系（P＜0.05);具有恶心、呕吐患者的口腔黏膜炎症的发病率较高,使用抗生素患者的口腔黏膜炎症的发病率要显著性低于未使用抗生素的患者,具有焦虑抑郁的患者发生口腔黏膜炎症的发病率会显著性的增加,随着住院天数的增加,患者发生口腔黏膜炎症的发病率会显著性的升高,两组比较均具有显著性的差异（P＜0.05）。结论:年龄、口腔疾患、含5-FU、抗生素、住院天数、焦虑抑郁等与头颈部的肿瘤化疗患者引起口腔黏膜炎症的发生率有一定的相关性。     

Risk of the Contralateral Mucosa in Patients with Oral Potentially Malignant Disorders

Background: It is known that abnormal changes may occur in any part of the oral mucous membraneexposed to a carcinogen. Therefore patients with oral potentially malignant disorders (PMDs) are at risk ofdeveloping similar lesions at multiple sites. Objectives: To determine the risk of the contralateral mucosa inpatients presenting with oral PMDs. Materials and methods: Sixty individuals with PMDs were selected for thisstudy. These comprised 32 (53.3%) Indians, 23 (38.3%) Chinese, four (6.7%) Malays and one (1.7%) Nepalese.All selected cases had histopathological confirmation of their primary existing lesion as inclusion criteria. Casesthat subsequently presented with a lesion in the corresponding anatomical site also underwent scalpel incisionalbiopsy on this second lesion to verify its diagnosis. The remaining cases that presented with unilateral PMDs atthe time of study were subjected to a cytobrush biopsy on the normal looking contralateral mucosa. Results: Atotal of 70 primary PMDs were detected in 60 patients. The most common PMD found was oral lichen planus(n=40, 57.1%). Of the 60 patients studied, 28 (46.6%) exhibited bilateral lesions either synchronously (n=21,35.0%) or metachronously (n=7, 11.6%). The remaining cases that had undergone cytobrush biopsy on thecorresponding anatomical site yielded normal cytological results. Conclusions: Present findings demonstratedthat patients presenting with PMDs in the upper aerodigestive tract are at a greater risk of developing a secondlesion most probably in the contralateral anatomical site.     

Paracoccidioidomycosis: a series of 66 patients with oral lesions from an endemic area

Paracoccidioidomycosis (PCM) is the most important systemic mycosis in Latin America. It has been regarded as a multifocal disease, with oral lesions as the prominent feature. To provide useful information concerning the diagnosis and management of the disease, this study describes demographic and clinical data from the medical records of a consecutive series of 66 Brazilian patients from an endemic area, evaluated in a referral centre for oral diagnosis. In this sample of patients, there was a predominance of middle‐aged male patients, who were primarily rural workers. Chronic multifocal disease was prevalent, with lesions also detected in the lungs, lymph nodes, skin or adrenal glands. Most of the cases presented with lesions at the gingival mucosa followed by the palate and lips; these conditions occurring in the oral cavity were frequently associated with pain. Importantly, most of the patients sought professional care for oral lesions. The diagnosis was obtained through exfoliative cytology and/or biopsy of the oral lesions. Medical treatment was effective, and there were no mortalities in the sample. The present findings not only confirm the importance of oral lesions in the diagnosis and management of PCM but also illustrate that questions still remain unclear, such as the possibility of direct inoculation of the fungus onto oral tissues.     

Factors influencing the severity of radiation skin and oral mucosal reactions: development of a conceptual framework

Radiation skin and oral mucosa reactions are common side-effects of head and neck radiation therapy caused by damage to normal tissue. This damage can be dose-limiting, meaning that the severity of acute reactions particularly in the oral mucosa may require time off treatment, potentially interfering with the effectiveness of radiation therapy in terms of tumour eradication. The purpose of this paper was to identify potential individual patient factors that may contribute to increasing severity of radiation skin and mucosal reactions. Sufficient literature and clinical observation is available to suggest that the variability in the degree of radiation reaction experienced by the patient is not due solely to the radiation received but that particular individual characteristics contribute to the expression of radiation damage in normal tissue. The identified factors fall into three broad categories: radiation therapy, genetic and personal factors. The research conducted on the predictive value of these factors is discussed. The inclusion of influencing factors in the assessment of people at risk for radiation skin and oral mucosa reactions has particular relevance for individualizing the prevention and management of radiation reactions.     

Relative Frequency of Oral Malignancies and Oral Precancer in the Biopsy Service of Jazan Province, 2009-2014

Background: The objective of this study was to report the types and relative frequency of oral malignancies and precancer in the Jazan region of Saudi Arabia during the period 2009-2014. Materials and Methods: Pathology reports were retrieved from the archives of Histopathology Department, King Fahd hospital in Jazan. Demographic data on tobacco habits, clinical presentation and histologic grading of oral precancer and cancer cases were transcribed from the files. Results: 303 (42.7%) oral pre-malignant and malignant cases were found out of 714 oral biopsy lesions. A pathology diagnosis of squamous cell carcinoma (85.1%) was most frequent, followed by premalignant lesions/epithelial dysplasia (8.6%), verrucous carcinoma (3.3%) and malignancy of other histological types (3%) such as ameloblastic carcinoma, salivary gland malignancy and sarcomas. Oral squamous cell carcinoma was predominant in females with a male to female ratio of 1:1.9. Patient age ranged from 22 to 100 years with a mean of 65±13.9. Almost 44.6% of oral cancer had occurred after 65 years of age. Only 16.3% cases were reported in patients younger than 50 years, predominantly females. The majority of female patients had the habit of using shammah with a long duration of usage for more than 45 years. Buccoalveolar mucosa (52.3%) was the common site of involvement followed by tongue/ floor of the mouth (47.7%) and clinically presented mostly as ulceration/swelling clinically. Moderately differentiated tumours (53.9%) were common followed by well differentiated (32.2%) and poorly differentiated tumours (5.8%). The prevalence of oral verrucous carcinoma (3.3%) was comparatively low with an equal distribution in both males and females. Both bucco-alveolar mucosa and tongue were predominantly affected. Oral precancer/epithelial dysplasia (8.6%) was common in females with a shammah habit. Bucco-alveolar mucosa was commonly involved and clinically presented mostly as white/red patches. Most cases were mild followed by moderate and severe dysplasia. Tumours of other histological types (3%) include 1 ameloblastic carcinoma, 3 malignant salivary gland tumours and 5 sarcomas. Conclusions: In this study, it was found that oral cancers reported in the pathology service to be a common occurrence. This study reconfirms previous reports of the high burden of oral cancer in this population This indicates that conventional preventive programs focused on oral cancer are in need of revision. In addition, further research into identifying new risk factors and molecular markers for oral cancer are needed for screening high risk individuals.     

Comparison of oral health assessments between nursing staff and patients on medical wards

The maintenance of good oral health is essential for nutrition, recovery and well-being. This requires the involvement of the nursing staff, especially in cases where oral care and any necessary dental treatment are vital to ensure medical treatment. The aim of this study was to evaluate the validity of oral assessments performed by nursing staff using the revised oral assessment guide (ROAG), using comparisons with patients' self-assessment of oral problems. When a comparison was made of how the staff and patients assessed their oral status, a high level of agreement was found. In these assessments, with the exception of oral mucosa and teeth, the percentage agreement was >80. The kappa coefficient revealed slight to moderate agreement. When there was a disagreement, the staff assessed the oral health as being significantly poorer than the patients did. In the present study, it was shown that few oral assessments performed by the nursing staff and patient disagreed. The ROAG may therefore be useful for the nursing staff to make the patients' oral health problems visible.     

Differential Expression of Cytokeratin 13 in Non-Neoplastic,Dysplastic and Neoplastic Oral Mucosa in a High Risk Pakistani Population

Background: Gradual loss of cytokeratin 13 (CK13) may be linked with the severity of dysplastic changesand transformation to malignancy. In this study we assessed the differential expression of CK13 in normal,hyperplastic, dysplastic and cancerous oral mucosa. Materials and Methods: A total of 93 oral biopsies werecollected during the 2011-2014 period. The biopsies were characterized as normal (19), hyperplastic (21), severelydysplastic/carcinoma in situ (16) and invasive oral squamous cell carcinoma (OSCC) (37) after morphologicalassessment. Formalin fixed paraffin embedded sections were stained with a monoclonal antibody against CK13using the Envision technique. Immunohistochemically stained slides were then analyzed for CK13 expression.Results: CK13 was consistently and diffusely expressed in all normal and hyperplastic tissue biopsies fromoral mucosa. Severely dysplastic/carcinoma in situ biopsies showed complete loss in 50% of cases, while in theremaining 50% expression was very focal and weak. OSCC cases showed complete or near complete loss ofCK13 in all cases. Few cases showed weak expression in keratin pearls only. Conclusions: This study validates theutility of CK13 IHC as a useful immunohistochemical marker in routine diagnostic practice to make distinctionbetween non-neoplastic from dysplastic and neoplastic (malignant) oral lesions.     

Field cancerisation of the oral cavity: Comparison of the spectrum of molecular alterations in cases presenting with both dysplastic and malignant lesions

Dysplastic lesions and invasive oral squamous cell carcinoma (SCC) from patients with field change were screened by restriction fragment length polymorphism (RFLP) and microsatellite assay. All tumours contained more genetic changes than the matched dysplasia which are likely to represent progression. Four of the 15 dysplastic lesions harboured the same abnormalities detected in the tumour and some paired lesions showed identical novel microsatellite alleles. The finding of identical ‘genetic fingerprints’ in dysplastic lesions and invasive carcinoma from the same patient provides strong evidence that these dysplasias are precursor lesions and that multiple lesions have probably arisen due to transfer of the progeny of an altered cell. Eight of the 15 dysplastic lesions showed alterations which were not present in the matched cancer, showing that evolution of subclones, or fusion of multiple clones also occurs. A further case showed loss of different alleles in the paired samples. These findings highlight the complexity of the genetic abnormalities present in the mucosa of patients with field change and suggests that the origin of these altered foci may be diverse.     

Cyclooxygenase-2 (COX-2) expression in high-risk premalignant oral lesions

Emerging data indicate a link between genetic instability and up-regulation of cyclooxygenase-2 (COX-2). To see if individuals at high risk of oral cancer are candidates for treatment with selective COX-2 inhibitors (coxibs), levels of COX-2 expression in healthy, premalignant and cancerous oral mucosa were compared with the occurrence of DNA ploidy status as a genetic risk marker of oral cancer. COX-2 gene product was evaluated immunohistochemically in 30 healthy persons, in 22 patients with dysplastic lesions without previous or concomitant carcinomas, and in 29 patients with oral carcinomas. The immunohistochemical findings were verified by western blotting. COX-2 expression was correlated to DNA content as a genetic risk marker of oral cancer. COX-2 was up-regulated from healthy to premalignant to cancerous oral mucosa. Thus, COX-2 expression was found in 1 case of healthy oral mucosa (3%). All specimens from healthy mucosa had a normal DNA content. In patients with premalignancies. In 29 patients with oral carcinomas, cyclooxygenase-2 expression was observed in 26 (88%), and aneuploidy was observed in 25 cases (94%, P=0.04). Notably, of 22 patients with dysplastic lesions, COX-2 was exclusively expressed in a subgroup of nine patients (41%) identified to be at high risk of cancer by the aberrant DNA content of their lesions. Seven of these patients were followed for 5 years or more. An oral carcinoma developed in six of them (85%; P=0.02). These findings emphasize the need to determine whether coxibs can reduce the risk of oral cancer in patients with high-risk precancerous lesions.     

Oral Cancer Knowledge,Attitudes and Practices among Primary Oral Health Care Dentists in Kuwait

Background: Oral cancer signifies a public health concern of international importance. Early detection of oral cancercan improve the prognosis and the 5-year survival rate. Objective: The aim of this study was to assess the level of oralcancer knowledge, opinion, attitudes and practices among dentists working at the primary oral health care centers inKuwait. Methods: In this cross-sectional study, self-reported questionnaire was distributed to the dentists working atthe primary oral health care centers in Kuwait. A total of 289 dentists participated in the present study. The questionnaireincluded 23- questions on oral cancer knowledge, opinion, attitudes and practices. Results: The mean age of the dentistswas 35.2 ± 10.9 years. Approximately, all dentists (99.7%) were aware of the major risk factors that were most likelyassociated with oral cancer. Overall, majority of the participants knew the most common form of oral cancer (80.6%),most common site (80.3%) and the likely lesions associated with oral cancer occurrence (87.9%). A large number ofdental practitioners (81%) would routinely refer a patient with a suspicious lesion to a specialist. Nearly one-third (32%)reviewed their patients’ oral cancer risk factors. Approximately two-thirds (62%) assessed the use of tobacco in theirpractice. Almost, all (92.4%) were interested in attending continuing education courses on oral cancer. Conclusions:Majority of the participants presented good knowledge about various aspects of oral cancer. More continuing educationprograms on risk factors and diagnosis of oral cancer should be organized to train the dentists. Oral cancer screeningshould be a routine procedure for the high risk patients at the primary oral health care centers in Kuwait.     

Clinical significance of altered expression of retinoid receptors in oral precancerous and cancerous lesions: relationship with cell cycle regulators

Alterations in expression of retinoid receptors are implicated in human cancers. We hypothesized that altered expression of retinoic acid receptors (RARalpha,beta,gamma) and retinoid X receptor RXRalpha and their relationship with cell cycle regulators (p53, p16, p21) is associated with development, progression and prognosis of oral cancer. Immunohistochemical analysis of RAR alpha, beta, gamma and RXRalpha proteins was carried out on serial sections from 244 oral squamous cell carcinomas (OSCCs), 102 potentially malignant lesions (65 hyperplasias, 37 dysplasias), 83 matched histologically normal oral tissues and 29 normal mucosa from non-exposed individuals without oral lesions and correlated with expression of cell cycle regulators p53, p16 and p21 as well as with clinicopathological parameters. Expression of retinoid receptors RARbeta, RARgamma, RXRalpha and cell cycle regulators p16 and p21 was decreased in majority of oral SCCs as well as in potentially malignant lesions. Multivariate stepwise logistic regression analysis carried out for comparison of non-exposed normal oral mucosa with histologically normal oral tissues from patients with oral lesions showed significant loss of RARbeta or p53 accumulation (RARbeta(-)/p53(+) Odd's ratio, OR = 266.6, p = 0.000); non-exposed normal mucosa from individuals without oral lesions with potentially malignant lesion was RARbeta(-)/p21(-)/p53(+) (OR = 215.7, p = 0.000); matched normal to potentially malignant stage was RARalpha(+)/p21(-) (OR = 4.414, p = 0.005); hyperplasia to dysplasia was RARalpha(+)/p53(+) (OR = 4.72, p = 0.005) and potentially malignant to malignant phenotype was RARalpha(+) (OR = 2.061, p = 0.004). The prognostic relevance of these factors was assessed in 115 of these SCC patients who were followed-up for a maximum period of 94 months (median 21 months). Multivariate analysis using Cox's proportional Hazard's model showed that RARalpha(+)/p21(-) phenotype was associated with shorter disease-free survival (Hazard's ratio, HR = 1.863, p = 0.0471). To our knowledge, this is the first large study showing alterations in expression of retinoid receptors at the protein level at different stages in development and progression of oral SCC. It also underscored the prognostic significance of retinoid receptors and their interactions with cell cycle regulators in multistep oral tumorigenesis.     

CO2 lasers in the management of potentially malignant and malignant oral disorders

The CO₂ laser was invented in 1963 by Kumar Patel. Since the early 1970s, CO₂ laser has proved to be an effective method of treatment for patients with several types of oral lesions, including early squamous cell carcinoma. Laser surgery of oral premalignant disorders is an effective tool in a complete management strategy which includes careful clinical follow-up, patient education to eliminate risk factors, reporting and biopsying of suspicious lesions and any other significant lesions. However, in a number of patients, recurrence and progression to malignancy remains a risk. CO₂ laser resection has become the preferred treatment for small oral and oropharyngeal carcinomas. Laser resection does not require reconstructive surgery. There is minimal scarring and thus, optimum functional results can be expected. New and improved applications of laser surgery in the treatment of oral and maxillofacial/head and neck disorders are being explored. As more surgeons become experienced in the use of lasers and as our knowledge of the capabilities and advantages of this tool expands, lasers may play a significant role in the management of different pathologies.     

Search for correlation between symptoms and signs of changes in the oral mucosa and presence of fungi

The aim of the present study was to determine the relationship between the symptoms and signs of oral mucosal changes and the presence of fungi. The investigation comprised 235 subjects. Fungi were detected in the oral cavities of 196 of these subjects. The fungi belonged to different species of the genus Candida. A significant correlation was found between the presence of fungi in the oral cavity and the existence of burning sensation, xerostomia, dysgeusia and non-idiopathic bleeding from the surface of the oral mucosa. A similar correlation was observed between the fungal colonization and atrophic changes, as well as reddened oral mucosa with lesions, ulceration and keratotic problems.     

p53 Overexpression in Oral Mucosa in Relation to Shisha Smoking in Syria and Lebanon

Introduction: Shisha (waterpipe) smoking is becoming a very prevalent form of tobacco consumption in the Middleeast and use is growing over the world. Smoking-related malignancies have a high genome-wide burden of mutations,including examples in the gene encoding p53. Aims: To investigate alterations in p53 immunohistochemical expressionin the normal, pre-malignant, malignant oral mucosa in relation to Shisha smoking habits. Materials and Methods:A total of 105 paraffin embedded tissue sections of OSCCs (52 smokers,53 non-smokers), 96 of premalignant lesions(48 smokers,48 non-smokers) and 60 normal oral mucosa. Some 30 patients with a history of Shisha smoking dailyfor more than 5 years were also investigated for mutant expression of p53. Tissue samples were considered positivefor p53 staining when any positive cells of epithelial origin could be detected. Results: The majority (74.3%) of oralsquamous cell carcinomas showed positive staining for p53 expression (83.1% and 65.5% with Shisha smokers andnon-smokers, respectively). In the 96 premalignant lesions, about 23% from non-smokers and 41.7% from smokersshowed p53 positivity. In normal epithelium, P53 positive cells were noted in 6.6% of non-smokers and 16.6% ofsmokers. Positive correlations with Shisha smoking were evident for the following groups: WDOSCC, MDOSCC,mild dysplasia G1, moderate dysplasia G2 and in normal mucosa using Student’s t- test, P valueThese results strongly suggest that p53 mutations are associated with Shisha smoking in OSCC, pre-malignant lesionsand normal mucosa of the oral cavity.     

Changed Expression of E-cadherin and Galectin-9 in Oral Squamous Cell Carcinomas but Lack of Potential as Prognostic Markers

Background: The survival rate for oral squamous cell carcinoma (OSCC) has remained generally unchangedin the past three decades, underlining the need for more biomarkers to be developed to aid prognostication andeffective management. The prognostic potential of E-cadherin expression in OSCCs has been variable in previousstudies while galectin-9 expression has been correlated with improved prognosis in other cancers. The aim ofthe present study was to investigate the expression of galectin-9 and E-cadherin in OSCC and their potentialas prognostic biomarkers. Materials and Methods: E-cadherin and Galectin-9 expression was examined byimmunohistochemistry in 32 cases of OSCC of the buccal mucosa (13 with and 19 without lymph node metastasis),as well as 6 samples of reactive lesions and 5 of normal buccal mucosa. Results: The expression of E-cadherin inOSCC was significantly lower than the control tissues but galectin-9 expression was conversely higher. MedianE-cadherin HSCOREs between OSCCs positive and negative for nodal metastasis were not significantly different.Mean HSCOREs for galectin-9 in OSCC without lymph node metastasis (127.7±81.8) was higher than OSCC withlymph node metastasis (97.9±62.9) but this difference was not statistically significant. Conclusions: E-cadherinexpression is reduced whilst galectin-9 expression is increased in OSCC. However, the present results suggestthat E-cadherin and galectin-9 expression may not be useful as prognostic markers for OSCC.     

Use of carbon dioxide laser for the treatment of premalignant lesions of the oral mucosa

The carbon dioxide laser was used for the treatment of 20 lesions of the oral mucosa in 14 patients. These lesions ranged histologically from benign hyperkeratosis to verrucous carcinoma. The patients selected for this treatment were identified at high risk to develop malignant lesions in the oral cavity. Precise vaporization of the affected mucosa were carried out using the Cavitron 40-300-A CO2 Surgical Laser. Destruction of the surface epithelium and submucosa was achieved by using defocused beam at a setting of 10W. Biopsies were taken at 1 cm intervals at the time of laser treatment. Fourteen of the 20 procedures were carried out under local anesthesia on an outpatient basis. Seven procedures were performed under general anesthesia and 2 patients required 24 h postoperative observation. Local control was achieved in 17 of the 20 treated sites. Two of the three treatment failures occurred in patients in whom the final histology revealed either in situ or invasive squamous carcinoma. Only one patient with dysplasia was not controlled after vaporization of the lesion by the carbon dioxide laser. The laser continues to show encouraging results as an alternative to surgical resection of precancerous mucosal lesions of the oral cavity. Vaporization of the dysplastic lesion(s) with carbon dioxide laser is recommended for patients with an identifiable risk for the development of intraoral malignancy. This is an effective, nonmorbid, inexpensive, quick, and relatively painless method of managing this condition.     

DNA ploidy analysis by image cytometry helps to identify oral epithelial dysplasias with a high risk of malignant progression

Abnormal DNA content (aneuploidy) has been associated with malignant and premalignant epithelial lesions. The presence of aneuploidy in tumours at an early stage and in dysplastic lesions suggests that analysis of DNA content may be a useful marker for determination of prognosis in these lesions. The aim of this study was to use DNA image cytometry to evaluate aneuploidy in oral dysplastic lesions and to determine whether aneuploidy is associated with malignant progression. Forty-two lesions of oral epithelial dysplasias (OED) that had progressed to oral squamous cell carcinoma (OSCC) and 44 lesions that did not progress were analysed for DNA ploidy using image cytometry of nuclear monolayers prepared from paraffin-embedded tissue. Forty-two OSCC that had arisen from the OED cases and five samples of normal oral mucosa samples (NOM) were also examined. Aneuploidy was found in 14/42 (33.3%) of the OED that progressed, but in only 5/44 (11.3%) of OED that did not progress (p=0.01). A total of 19 OED were aneuploid of which 74% showed malignant progression compared to only 42% of the diploid lesions. The sensitivity and specificity of DNA image cytometry to detect cases with high risk of malignant progression was 0.33 and 0.88, respectively. The PPV and NPV were 0.74 and 0.58. We conclude that aneuploid oral dysplastic lesions have a high risk of malignant progression and that DNA image cytometry might help to identify those lesions most at risk.