Observations on the clinical characteristics of oral lesions showing histologic epithelial dysplasia

Oral erythroplakia--a review

Oral erythroplakia (OE) is considered a rare potentially malignant lesion of the oral mucosa. Reports entirely devoted to OE are very few, and only two reviews none of which are of recent date have been published. Only the true, velvety, red homogeneous OE has been clearly defined while the terminology for mixed red and white lesions is complex, ill-defined and confusing. A recent case control study of OE from India reported a prevalence of 0.2%. A range of prevalences between 0.02% and 0.83% from different geographical areas has been documented. OE is predominantly seen in the middle aged and elderly. One study from India showed a female:male ratio of 1:1.04. The soft palate, the floor of the mouth and the buccal mucosa is commonly affected. A specific type of OE occurs in chutta smokers in India. Lesions of OE are typically less than 1.5 cm in diameter. The etiology of OE reveals a strong association with tobacco consumption and the use of alcohol. Histopathologically, it has been documented that in OE of the homogenous type, 51% showed invasive carcinoma, 40% carcinoma in situ and 9% mild or moderate dysplasia. Recently, genomic aberrations with DNA aneuploidy has been demonstrated. p53 mutations with different degrees of dysplasia may play a role in some cases of OE. Transformation rates are considered to be the highest among all precancerous oral lesions and conditions. Surgical excision is the treatment of choice. Data on laser excision are not available. Recurrence rates seem to be high, reliable data are, however, missing. More studies on OE are strongly needed to evaluate a number of so far unanswered questions. The natural history of OE is unknown. Do OEs develop de novo or are they developing from oral leukoplakia through several intermediate stages of white/red lesions? The possible role of fungal infection (Candida micro-organisms) is not clear as is the possible role of HPV co-infection in the development of OE. More data on incidence and prevalence, biological behaviour and adequate treatment are urgently needed.

Bioinformatics in Otolaryngology

This article reviews the recent literature on microarray analysis, bioinformatics techniques, and genomics in relation to the study of carcinogenesis of head and neck cancers.

Overexpression of matrix metalloproteinase-1 and -9 mRNA is associated with progression of oral dysplasia to cancer

PURPOSE

Although an important risk factor for oral cancer is the presence of epithelial dysplasia, many lesions will not progress to malignancy. Matrix metalloproteinases (MMPs) are zinc-dependent proteinases capable of digesting various structural components of the extracellular matrix. Because MMPs are frequently overexpressed in oral squamous cell carcinoma (SCC), we hypothesized that they are also overexpressed in oral dysplasias; we also hypothesized that those dysplasias that progress to oral cancer express higher levels of MMPs than those lesions that do not progress.

EXPERIMENTAL DESIGN

In this retrospective study, we examined changes in MMP-1, -2, and -9 mRNA expression using quantitative TaqMan reverse transcription-polymerase chain reaction in 34 routinely processed oral dysplasias and 15 SCCs obtained from 34 patients. After several years of close follow-up, 19 dysplasias progressed to oral SCC and 15 did not.

RESULTS

Overall, MMP-1 mRNA was overexpressed (>2-fold) in 24 of 34 (71%) dysplasias and 13 of 15 (87%) oral SCCs. MMP-2 overexpression was seen in 11 of 34 (32%) dysplasias and 7 of 15 (47%) cancers; for MMP-9, overexpression was identified in 29 of 34 (85%) dysplasias and 15 of 15 (100%) cancers. MMP-1 and -9 levels were significantly higher in the SCCs compared with all oral dysplasias (P = 0.004 and P = 0.01, respectively). MMP-1 and -9 mRNA levels were significantly higher in the oral dysplasias that progressed to oral cancer compared with those that did not (P = 0.04 and P = 0.002, respectively).

CONCLUSIONS

Levels of MMP-1 and -9 mRNA may be markers of malignant transformation of oral dysplasia to oral cancer.

Cytologic and DNA-cytometric follow-up of oral leukoplakia after CO2- and Er:YAG-laser assisted ablation: A pilot study

BACKGROUND AND OBJECTIVES

The aim of the present pilot study was to determine therapeutic responses to Er:YAG- and CO(2)-laser ablation in patients with oral leukoplakia as evaluated by means of exfoliative cytology (EC) and DNA-image-cytometry (DNA-I).

STUDY DESIGN/MATERIALS AND METHODS

Ten patients exhibiting a total of 16 lesions affecting a variety of intraoral sites were randomly treated with either (1) an Er:YAG laser (300 mJ/pulse, 10 Hz, defocused mode) (ERL), or (2) an CO(2) laser (4-6 W, 20-50 Hz, focused mode) (CO). Brush (B) and incisional (I) biopsies were obtained from the respective lesions immediately before treatment (B, I) as well as 24-96 weeks postoperatively (B). In cases, in which EC revealed suspicious cells, nuclear DNA-contents were measured using a TV image analysis system.

RESULTS

Both treatment approaches resulted in a complete (C) or partial (P) remission of all investigated lesions. In particular, ERL exhibited C(3), P(5), and CO C(5), P(3). However, in the CO group, two of eight lesions showed a recurrence 32-48 weeks following treatment. Among all investigated lesions, both histological and EC/DNA-I diagnosis revealed no sign of malignancy or dysplasia before or following laser assisted ablation.

CONCLUSIONS

Within the limits of the present study, it may be concluded that both treatment approaches seem to have limitations to achieve predictable eradication of oral leukoplakia.

Head and neck cancer: The pursuit of molecular diagnostic markers

From a histopathologic perspective, head and neck squamous cell carcinoma (HNSCC) is a relatively straightforward diagnosis. However, the clinically useful information presently provided by pathologists is embarrassingly limited. Similarly, our ability to accurately identify the earliest premalignant lesions as well as predict which premalignant lesions are likely to progress to HNSCC is limited. Over the last decade, an explosive growth of knowledge related to the molecular biology of this disease has occurred, which is now being used to address these issues. For example, we now appreciate that there are multiple etiologies and multiple molecular mechanisms responsible for the development of HNSCC. New techniques have improved our ability to identify molecularly premalignant, but histologically benign lesions. Similarly, recent studies have been able to predict which premalignant lesions are likely to progress to HNSCC. In addition to having utility in the realm of early diagnosis, molecular diagnostics may have a profound impact on how we diagnose and report HNSCC. While still in the developmental stage, molecular protocols are being used to evaluate surgical margins, determine the location of unknown primary tumors, identify histologically undetectable lymph node metastasis, and predict which tumors are more likely to respond to a particular postsurgical adjuvant therapy.

Smokeless tobacco and oral cancer: a review of the risks and determinants

Smokeless tobacco has been associated with oral cancer for many decades. The purpose of this article is to review research relevant to this association, including epidemiologic studies, studies of putative carcinogens such as tobacco-specific nitrosamines (TSNAs) and other contaminants, and possible cancer inhibitors. Epidemiologic studies addressing this issue primarily consist of case-control studies. They show that the use of chewing tobacco and moist snuff is associated with very low risks for cancers of the oral cavity and related structures (relative risks [RR] from 0.6 to 1.7). The use of dry snuff is associated with higher RRs, ranging from 4 to 13, while the RRs from smokeless tobacco, unspecified as to type, are intermediate (RR = 1.5 to 2.8). With regard to TSNAs, historical levels in American moist snuff products were higher than those in their Swedish counterparts, but levels in contemporary products are uniformly low. TSNA levels in chewing tobacco have always been low, but levels in dry snuff have been higher, including some very high levels in current products. In general, smokeless tobacco users are not exposed to significant levels of cadmium, lead, benzo(a)pyrene, polonium-210, and formaldehyde, when compared with concentrations of these compounds in foods. Finally, low oral cancer risk from smokeless tobacco use may be influenced by the presence of cancer inhibitors, mainly anti-oxidants, in smokeless tobacco products.

Management of oral leukoplakia by laser surgery: relation between recurrence and malignant transformation and clinicopathological features

OBJECTIVE

The aim of the present study was to assess the clinical usefulness of laser surgery for oral leukoplakia.

BACKGROUND

Recurrence and/or malignanT transformation of oral leukoplakia have occasionally been observed following laser surgery. It is reported that the rate of recurrence was 7.7-38.1%, while malignant transformation was 2.6-9%.

MATERIALS AND METHODS

A total of 154 oral leukoplakias from 116 patients were treated in our department. Comparisons with the rate of recurrence, malignant transformation and clinical futures, epithelial dysplasia, location, and treatment procedure were examined. To evaluate recurrence and malignant transformation, the cases were restricted to those with a minimum follow-up of 6 months.

RESULTS

A total of 97 lesions fulfilled this criterion. The rate of recurrence had no association with the location or the epithelial dysplasia, although it differed with the treatment procedure. The rate of recurrence in laser surgery was approximately 29%. Malignant transformation was observed in four of 97 lesions. They were observed in 13.6% of tongue cases and 1.8% of gingival cases. Three of four lesions were treated with excision surgery, and the remaining one treated with laser vaporization. Only 1.2% malignant transformation in laser surgery was revealed.

CONCLUSION

Laser excision is suitable for leukoplakia cases on non-keratinized epithelia (i.e., the tongue and buccal mucosa), while laser vaporization is suitable for the gingival cases. Management of oral leukoplakia prevents not only recurrence and malignant transformation, but also postoperative dysfunction. We believe that laser surgery is an excellent procedure.

The pathology of oral cancer

Oral cancer is a serious public health problem, with over 200,000 new cases reported annually worldwide, two-thirds of which occur in developing countries. The overall mortality rate for intra-oral cancer remains high at approximately 50%, even with modern medical services, probably due to the advanced stage of the disease at presentation. This review outlines recent advances in our understanding of the roles and interactions of major risk factors for oral cancer worldwide, notably tobacco, alcohol and betel quid and the genetic polymorphisms determining their metabolism that may predispose patients to oral carcinoma. Oral epithelial lesions with malignant potential are described. We discuss the histopathology of oral cancer, its grading and the staging of the disease at clinical, microscopic, immunohistological and molecular levels. A recommended minimum dataset for pathology reports is described. The available strategies and current prospects for controlling oral cancer in the community are summarised.

Laser surgery as a treatment for oral leukoplakia

Various treatment procedures for oral leukoplakia have been reported. However, after some treatments, oral leukoplakia show recurrence and/or malignant transformation, even following complete resection. Furthermore, patients with oral leukoplakia may develop new lesions in other oral cavity locations. Laser surgery for oral mucosal lesions has been reported to have many advantages, and it is widely used in the treatment of oral leukoplakia. In previous studies, recurrence and malignant transformation from the lesion have occasionally been observed following laser surgery. We reviewed the records of oral leukoplakia patients treated with laser surgery to assess its clinical usefulness. It has been reported that the rate of recurrence was 7.7-38.1%, while malignant transformation was 2.6-9% for oral leukoplakia treated with laser surgery. In the present study, there was 29.3% recurrence and 1.2% malignant transformation after laser surgery. This was similar to previous findings. This suggests that non-homogeneous leukoplakia on nonkeratinized epithelia, i.e. the tongue mucosa has a high risk for malignant transformation, so lesions should be excised after detecting abnormal epithelia using vital tissue staining. The wound healing process after laser surgery was satisfactory and no significant complications were observed. Management of oral leukoplakia prevents not only recurrence and malignant transformation, but also postoperative dysfunction: laser surgery is an excellent procedure that is able to overcome these problems.

Development of the Bowman-Birk inhibitor for oral cancer chemoprevention and analysis of Neu immunohistochemical staining intensity with Bowman-Birk inhibitor concentrate treatment

OBJECTIVES/HYPOTHESIS

Cancer chemoprevention is a rapidly evolving approach to reverse or inhibit carcinogenesis, and there is active interest in development of effective chemopreventive agents against head and neck cancers. The retinoids are archetypal chemopreventive agents for oral premalignant lesions. They have significant clinical effect, but widespread use is limited by significant clinical toxicity. The Bowman-Birk Inhibitor is one of several nontoxic compounds exhibiting both potent anticarcinogenic activity and minimal toxicity. The purposes of the study were to summarize the preclinical and clinical development of Bowman-Birk Inhibitor and a Bowman-Birk Inhibitor concentrate against oral premalignant lesions and to evaluate Neu immunohistochemical staining intensity for lesions and simultaneously obtained biopsy specimens of normal-appearing mucosa from the Phase IIa Bowman-Birk Inhibitor concentrate oral leukoplakia chemoprevention trial.

STUDY DESIGN

Part I is a selected literature review. Part II is a retrospective analysis of pathological specimens prospectively obtained from the Phase IIa clinical trial of Bowman-Birk Inhibitor concentrate.

METHODS

Thirty-two sets of biopsy specimens from lesions and uninvolved oral mucosa before and after treatment with Bowman-Birk Inhibitor concentrate in doses ranging from 200 to 1066 chymotrypsin inhibitory units were examined in blinded fashion for Neu immunohistochemical staining intensity using the 3B-5 monoclonal antibody. Staining intensity scores among the lesion and control biopsy specimens before and after Bowman-Birk Inhibitor concentrate treatment were analyzed and compared with previously obtained values for serum Neu, oral mucosal cell Neu, protease activity, and clinical response to treatment.

RESULTS

Mean Neu staining score was significantly higher in lesions compared with uninvolved mucosa (P <.001). Pretreatment staining scores for biopsy specimens of lesions and control biopsy specimens of normal-appearing tissues were correlated (Spearman correlation coefficient [r] = 0.375, P =.045), but no correlation between lesion and control biopsy specimen scores was evident after treatment. The change in Neu staining score with Bowman-Birk Inhibitor concentrate treatment in control site biopsy specimens demonstrated an inverse relationship of change in lesion area with Bowman-Birk Inhibitor concentrate treatment (Spearman r = -0.493, P <.007).

CONCLUSION

Bowman-Birk Inhibitor concentrate shows promise to become an effective nontoxic chemopreventive agent based on results of extensive preclinical studies, and Phase I and Phase IIa clinical trials. Bowman-Birk Inhibitor concentrate has dose-related clinical activity against oral leukoplakia and modulates levels of Neu and protease activity. The current investigation identified increased Neu staining intensity in hyperplastic lesions compared with simultaneously obtained biopsy specimens of normal-appearing mucosa both before and after Bowman-Birk Inhibitor concentrate treatment. This finding supports prior observations that increased Neu expression is present in a subset of oral premalignant lesions and head and neck cancers. The trend of increased Neu staining score in control biopsy tissues of subjects exhibiting decreased lesion area following Bowman-Birk Inhibitor concentrate treatment raises questions about the mechanisms of Bowman-Birk Inhibitor concentrate action. One possible explanation is that Bowman-Birk Inhibitor stabilizes the extracellular domain of Neu, thereby preventing receptor truncation and internalization. Further study of modulation of Neu and protease activity by Bowman-Birk Inhibitor concentrate treatment may provide insights into the role of proteases and protease inhibitors in oral premalignant lesions and the mechanisms underlying Bowman-Birk Inhibitor concentrate effects. A Phase IIb randomized, placebo-controlled clinical trial to determine the clinical effectiveness of Bowman-Birk Inhibitor concentrate and further evaluate these candidate biomarkers is under way.

Quantitative analysis of cathepsin L mRNA and protein expression during oral cancer progression

Although an important risk factor for oral cancer is the presence of epithelial dysplasia, most of these lesions will not progress to malignancy. Presently, for the individual patient with dysplasia, there are few reliable markers that may indicate the likelihood of progression to oral cancer. Cathepsin L is a lysosomal protease that degrades extracellular matrix material. Because cathepsin L is frequently overexpressed in oral squamous cell carcinoma (SCC) we hypothesized that it is also overexpressed in oral premalignancy and that premalignant lesions that progressed to oral cancer expressed higher levels of cathepsin L than those premalignant lesions that did not. In this retrospective pilot study we examined changes in cathepsin L expression at the mRNA level using quantitative TaqMan RT-PCR and at the protein level by immunohistochemistry in 33 routinely processed oral dysplastic lesions and 14 SCCs obtained from 33 patients. Sixteen of the dysplastic lesions progressed to oral SCC and 17 did not after several years of follow-up. Cathepsin L mRNA was overexpressed in 16/33 (48%) dysplastic lesions and in 9/14 (64%) oral SCC. Cathepsin L protein was also overexpressed in a large proportion of dysplasias and cancers. Overexpression was independent of dysplasia grade and identified in both those patients who progressed to oral SCC and in those who did not. Levels of cathepsin L mRNA and protein did not differ significantly in the progressing versus non-progressing dysplasias (P=0.27). However, cathepsin L mRNA and protein were significantly lower in the non-progressing dysplasias when compared to the oral cancers (P=0.03) but not in the progressing dysplasias suggesting a trend for dysplasias with overexpressed cathepsin L to be more likely to progress to oral cancer.

Immunohistochemical study of syndecan-1 down-regulation and the expression of p53 protein or Ki-67 antigen in oral leukoplakia with or without epithelial dysplasia

BACKGROUND

Leukoplakia is an oral pre-cancerous lesion that sometimes develops into squamous cell carcinoma. Therefore, leukoplakia with epithelial dysplasia is useful for studying carcinogenesis at the cellular level. The purpose of this study was to evaluate a potential association between the loss of syndecan-1 expression and the expression of p53 protein and Ki-67 antigen, and to identify reliable markers for predicting malignant changes in oral leukoplakia with epithelial dysplasia.

METHODS

Changes in the expression of syndecan-1, p53, and Ki-67 were examined immunohistochemically in 43 cases of oral leukoplakia with or without epithelial dysplasia. The subjects were categorized as: none, 13 cases; mild dysplasia, 5 cases; moderate dysplasia, 17 cases; and severe dysplasia, 8 cases. The expression of these molecules in normal oral epithelia (22 cases) was also investigated.

RESULTS

Strong syndecan-1 expression was observed on the surface of keratinocytes in normal epithelium. Immunopositivity was lost gradually as the extent of epithelial dysplasia increased. In normal epithelium, p53 and Ki-67 appeared mainly in the basal cell layer, while they were more widely distributed in leukoplakia. Specifically, significant changes were observed in the labeling index of p53 and Ki-67 in leukoplakia as epithelial dysplasia progressed from mild to moderate or severe.

CONCLUSION

Our results reveal that overexpression of p53 protein and Ki-67 antigen, and down-regulation of syndecan-1 expression in the lower part of the epithelium, are associated with dysplastic changes. Therefore, the down-regulation of syndecan-1 expression may be the most important reliable marker for dysplastic changes.

Oral epithelial dysplasia: clinical characteristics of western European residents

To detail the clinical presentation of oral epithelial dysplasia in a large cohort of residents in western Europe. Descriptive statistical analysis of the data were calculated using chi-square and Fisher's exact tests. Oral epithelial dysplasia manifested typically as a white or mixed red and white lesion on the tongue, buccal mucosa or floor of mouth. The peak age of presentation of oral epithelial dysplasia was the 6th decade. Most clinically detected lesions had only mild oral epithelial dysplasia. Although uncommon, lesions with severe dysplasia were most likely to arise on the floor of mouth or lateral border of tongue. Oral epithelial dysplasia is likely to manifest as a solitary white patch, but it is not possible to accurately predict the likely degree of dysplasia from the clinical features of such lesions.

Prognosis of oral pre-malignant lesions: significance of clinical, histopathological, and molecular biological characteristics

The concept of a two-step process of cancer development in the oral mucosa, i.e., the initial presence of a precursor subsequently developing into cancer, is well-established. Oral leukoplakia is the best-known precursor lesion. The evidence that oral leukoplakias are pre-malignant is mainly derived from follow-up studies showing that between < 1 and 18% of oral pre-malignant lesions will develop into oral cancer; it has been shown that certain clinical sub-types of leukoplakia are at a higher risk for malignant transformation than others. The presence of epithelial dysplasia may be even more important in predicting malignant development than the clinical characteristics. Three major problems, however, are attached to the importance of epithelial dysplasia in predicting malignant development: (1) The diagnosis is essentially subjective, (2) it seems that not all lesions exhibiting dysplasia will eventually become malignant and some may even regress, and (3) carcinoma can develop from lesions in which epithelial dysplasia was not diagnosed in previous biopsies. There is, therefore, a substantial need to improve the histologic assessment of epithelial dysplasia or, since epithelial dysplasia does not seem to be invariably associated with or even a necessary prerequisite for malignant development, it may be necessary to develop other methods for predicting the malignant potential of pre-malignant lesions. As a consequence of these problems, numerous attempts have been made to relate biological characteristics to the malignant potential of leukoplakias. Molecular biological markers have been suggested to be of value in the diagnosis and prognostic evaluation of leukoplakias. Markers of epithelial differentiation and, more recently, genomic markers could potentially be good candidates for improving the prognostic evaluation of precursors of oral cancer. As yet, one or a panel of molecular markers has not been determined that allows for a prognostic prediction of oral pre-cancer which is any more reliable than dysplasia recording. However, these new markers could be considered complementary to conventional prognostic evaluation.

Potentially malignant oral lesions in Northern Ireland: size (extent) matters

OBJECTIVES

We examined clinical parameters of patients from Northern Ireland with potentially malignant lesions (PML) to determine association with development of intraoral squamous cell carcinoma (SCC).

DESIGN

retrospective, cross-sectional, population-based, clinically validated, laboratory-verified.

SUBJECTS AND METHODS

All patients who had more than one incisional oral mucosal biopsy diagnosed from 1975-1991 were abstracted from a database of all PML and SCC and their clinical records and biopsies reviewed. Patients were excluded if there was priorlsynchronous SCC or radiotherapy, frictional keratosis or lichen planus, missing clinical records/biopsy material or follow-up of <24 months. From the 50 suitable patients, gender, age, smoking status, site, clinical appearance and extent of lesion(s), treatment and year of diagnosis were recorded. Patients who developed SCC from PML were compared with those who did not.

RESULTS

Squamous cell carcinoma occurred significantly more often in patients with single rather than multiple PML, those with 'non-homogenous' PML and in patients diagnosed prior to 1980. In Cox's survival analysis, only the clinical extent was predictive of SCC.

CONCLUSIONS

Of all the features considered in our series, size (extent) was the most important clinical factor in determining the risk of future SCC in PML, particularly when several adjacent anatomical sites were affected.

Bcl-2 expression in sequential biopsies of potentially malignant oral mucosal lesions assessed by immunocytochemistry

OBJECTIVE

To examine, for the first time Bcl-2 expression in sequential (autogenous) oral mucosal biopsies taken from the same sites in a gender, risk-factor matched, Caucasoid sample, over a 21-year period.

DESIGN

Retrospective immunocytochemical longitudinal study of archival serial biopsies.

MATERIALS AND METHODS

Computer records were used to identify biopsy specimens derived from 12 patients. These were divided into four groups: (1) Histologically innocuous lesions which remained histologically innocuous. (2) Dysplastic lesions which remained dysplastic. (3) Histologically innocuous lesions which later progressed to squamous cell carcinoma (SCC). (4) Dysplastic lesions which later progressed to SCC. This represented 65 biopsies in total. Bcl-2 expression was studied using mouse antihuman BCL-2 oncoprotein clone 124 (Dako, Denmark).

RESULTS

Generally, there was a lack of Bcl-2 immunoreactivity in the epithelium, with one exception in dysplastic epithelium from a group (3) patient.

CONCLUSION

These findings suggest that in our series, Bcl-2 is not expressed early in oral premalignant lesions and appears to contradict previous reports. Possible explanations for this disparity are considered.

Direct oral microscopy and its value in diagnosing mucosal lesions: a pilot study

OBJECTIVE

Clinical examination of the oral mucosa often leads to an uncertain diagnosis, and a supplementary biopsy with a histopathologic examination of the lesion is necessary to establish a definite diagnosis. However, the site for the biopsy is a subjective choice that sometimes raises doubts about its representativeness. So far, no simple and reliable method is available for selecting the most appropriate area for biopsy.

STUDY DESIGN

In a prospective study, we performed direct oral microscopy (oral application of the colposcopy technique used in gynecology) in 35 patients with various clinical diagnoses, such as leukoplakia, oral lichenoid lesions, or suspected malignancy. First, the oral mucosa was examined with direct microscopy, and the most representative site, according to colposcopic criteria, was selected. Then, the mucosa was clinically inspected by an independent examiner. The best site for biopsy according to clinical criteria was noted, and any difference in biopsy sites was recorded. Biopsy specimens were taken from 2 of these sites.

RESULTS

Twenty-nine patients (83%) showed changes in the vascular picture on microscopy, according to the colposcopy criteria. In 14 patients (40%), the biopsy sites identified by direct oral microscopy showed more advanced histologic signs than those selected by routine clinical examination (0.01 < P </=.05). Four patients (11%) had more advanced histologic signs in the biopsy samples, as identified during routine clinical examination. In 17 patients (49%), we found no differences between the biopsy specimens.

CONCLUSION

Direct oral microscopy of mucosal lesions seems to offer advantages in selecting more representative sites for biopsy than routine clinical examination alone.

Sanguinaria-associated oral leukoplakia: comparison with other benign and dysplastic leukoplakic lesions

OBJECTIVE

This study was undertaken to compare and contrast biomarkers and ploidy data from maxillary gingiva leukoplakias associated with dentifrices and mouthrinses containing the herbal compound sanguinaria with other forms of oral benign and premalignant mucosal keratosis.

STUDY DESIGN

Representative archived specimens of benign keratosis, sanguinaria-associated keratosis, and keratosis with dysplasia were used for computerized image analysis and biomarker immunohistochemical assays to assess ploidy, DNA content, and p53 and proliferating cell nuclear antigen immunoreactivity of nuclei.

RESULTS

DNA content was significantly higher and higher numbers of cell populations with hyperploid nuclei were encountered in the dysplastic group than in the other two groups (P <.001). Sanguinaria-associated keratosis did not harbor significant numbers of p53-expressing nuclei, yet it showed a significant elevation in proliferating cell nuclear antigen-labeled nuclei in total, in the basal layer, and in the spinous layer in comparison with benign keratoses (P <.001). In addition, 1.5% of the sanguinaria-associated leukoplakia epithelial cell population was characterized by nuclei with a greater than 4-fold increase in DNA content.

CONCLUSIONS

Sanguinaria-associated keratoses show some marker and image analysis profiles similar to those of non-sanguinaria dysplastic lesions of the lip and mucosa. Preparations containing sanguinaria should be avoided until the risk for malignant transformation is determined.

p53 gene mutations in sequential oral epithelial dysplasias and squamous cell carcinomas

Previous studies of oral cancer have suggested that alterations of the p53 tumour suppressor gene occur early in the precancerous stage of development. However, these observations have been based on cross-sectional assessment of abnormal p53 protein staining by immunohistochemistry and may not necessarily reflect gene changes. The purpose of this longitudinal study was to examine the changes in the p53 gene in progressive, sequential epithelial dysplasias and carcinomas from the oral cavity. The study analysed 24 formalin-fixed, paraffin-embedded tissue biopsies from ten patients with two or more temporally distinct lesions from the same site in the oral cavity with the diagnosis of hyperkeratosis, epithelial dysplasia, carcinoma in situ or squamous cell carcinoma. Exons 5-8 of the p53 gene were amplified from genomic DNA using intronic primers and directly sequenced using fluorescent-labelled primers. Standard immunohistochemistry with the DO7 monoclonal antibody was used to detect mutant and wild-type p53 protein. Mutations of the p53 gene were identified in 9 of 24 samples. Eight were missense mutations and one occurred at a splice site. In six patients, mutations of the p53 gene occurred late after the transformation of epithelial dysplasia to carcinoma. In two patients with progressive dysplasia, but who had yet to develop invasive carcinoma, p53 missense mutations occurred at the carcinoma in situ stage in one case and in a moderate dysplasia in the other. There was an inconsistent relationship between gene mutations and the level of p53 protein staining by immunohistochemistry. It is concluded that during oral carcinogenesis, p53 gene mutations seem to occur relatively late and are associated with transformation to the invasive phenotype.

Current concepts in oral cancer

Over 750 new intra-oral squamous cell carcinomas are registered in Australia each year. In this article, the authors review the epidemiology, aetiology, genetics and spread of intra-oral squamous cell carcinoma. The mechanisms of field cancerization are discussed. The prevention of intra-oral squamous cell carcinoma is highlighted and future treatments are presented.

A comparison of the management of potentially malignant oral mucosal lesions by oral medicine practitioners and oral & maxillofacial surgeons in the UK

This study describes the results of a survey undertaken to assess the management of potentially malignant oral mucosal lesions by oral medicine practitioners and compares their approach with that of oral & maxillofacial surgeons that we have previously described. Significant differences were noted between the two groups in the use of photography to document the lesions and in the use of certain special investigations, which included measurement of serum iron, serum ferritin, serum Vit B12, red cell folate and candidal isolation. The groups also varied in the perceived importance of the age of the patient and anatomical site of the lesion when deciding on the need for further biopsy. There was also significant variation in the use of certain treatment modalities, including excising non-dysplastic and severely dysplastic/carcinoma in-situ lesions and eliminating trauma when treating mild/moderately dysplastic and severely dysplastic/carcinoma in-situ lesions. Significant differences in the frequency and duration of follow-up were noted for non-dysplastic lesions. Finally, the two groups differed significantly when asked to rank the perceived importance of certain factors (the histopathology of the most recent biopsy and the anatomical site of the lesion) when deciding the need to follow-up. Possible reasons for the variation are discussed.

Flow cytometric analysis of cell cycle fractions in oral leukoplakia

Flow cytometric analysis of cell cycle fractions and DNA ploidy was performed on 39 biopsy specimens of oral leukoplakia. The aneuploidy rate of these leukoplakias was 9/39 (23.1%) and the mean DNA index of the aneuploid lesions was 1.34. The aneuploidy rate was significantly higher in severely dysplastic lesions (8/17) than in mildly dysplastic (1/15, P<0.02) and nondysplastic (0/7, P<0.05) lesions. No significant differences in the percentages of each cell cycle fraction were seen between the diploid and the aneuploid leukoplakias. However, the S-phase fraction of the severely dysplastic lesions (23.0%) among the diploid leukoplakias was higher than those of the mildly dysplastic (12.4%) and nondysplastic (15.5%) lesions, and the difference between the severely dysplastic and the mildly dysplastic lesions was statistically significant (P<0.001). These results suggest that flow cytometric analysis of cell cycle fractions and DNA ploidy might offer additional information for assessing the malignant potential of oral leukoplakias.

The effects of platelet-derived growth factor-BB and insulin-like growth factor-1 on epithelial dysplasia

Growth factors are multi-functional and multi-targeted proteins which play a significant role in wound healing. Platelet-derived growth factor B-chain homodimer (PDGF-BB) and insulin-like growth factor-1 (IGF-1) have demonstrated efficacy for periodontal regeneration in animal models. Although primarily associated with wound healing, PDGF-BB and IGF-1 also facilitate growth of a number of malignant neoplasms. Of particular concern to periodontists is epithelial dysplasia, a necessary precursor to squamous cell carcinoma, the most common oral malignancy. Certain risk factors for oral cancer, such as tobacco, age, and alcohol, are also associated with an increased incidence of periodontal disease. The effects of the combination of PDGF-BB and IGF-1 on epithelial dysplasia have not previously been reported. The purpose of this study was to examine the effects of the combination of PDGF-BB and IGF-1 on epithelial dysplasia induced in the buccal cheek pouch of the Syrian golden hamster. A total of 66 hamsters received 18 applications of 0.5% dimethylbenzanthracene (DMBA), a topical carcinogen, over a 6-week period for the induction of dysplasia. The hamsters were subsequently divided into a baseline and 3 experimental groups (growth factors, saline vehicle, untreated control). Following the final DMBA application (day 0), the baseline group (N = 6) was sacrificed, the growth factor group (N = 21) received a single injection in the cheek pouch containing 4 micrograms of PDGF-BB and 4 micrograms of IGF-1 in saline, the saline group (N = 19) received an injection in the cheek pouch containing the saline vehicle only, and the untreated control group (N = 20) received no injection. Animals in experimental groups were sacrificed on days 3, 6, and 10. The cheek pouches were harvested for histologic and histochemical evaluation. Dysplasia was histologically graded from 0 to 4. Statistical analysis of the histologic data revealed no significant differences either by sacrifice date or by group. Histochemical evaluation, via staining for gamma-glutamyl transpeptidase (GGT), a marker for dysplastic cell colonies, revealed that the density of GGT-positive cells in experimental groups differed significantly from baseline levels. No significant differences were detected between experimental groups. There was poor correlation between the density of GGT-positive cells and the histologic grading of dysplasia. It is concluded that exposure to PDGF-BB and IGF-1 had no demonstrable effect on epithelial dysplasia in this hamster model.

Nuclear morphometry in experimental oral mucosal carcinogenesis

The area, perimeter and diameter of basal cell nuclei of rat palatal epithelium were measured and the deviation of the basal cell nuclear profile from the form of a sphere was assessed after the application of the carcinogen 4-nitroquinoline-1-oxide (4NQO). After a 24-week treatment-free period, designed to eliminate the irritant effect of the carcinogen, the rats were killed, the palatal mucosa was recovered and processed and the nuclear histometry was assessed with image analysis techniques. The basal cell nuclear area increased as the epithelium became dysplastic and then decreased as carcinoma developed, but there were significant variations in this parameter in the control groups. Basal cell nuclei from moderately or severely dysplastic epithelium, and from epithelium adjacent to areas of invasive carcinoma, were significantly less regular in profile by comparison with control nuclei. Variations in nuclear profile, but not nuclear area, perimeter or diameter, might reflect fundamental nuclear alterations of significance during the process of carcinogenesis.

Tobacco use and cancer. A reappraisal

With approximately six million users, smokeless tobacco has received considerable scrutiny as a risk factor for oral cancer. We review the relationship between smokeless tobacco use, keratosis, and oral cancer. Several features of smokeless tobacco keratosis, including the natural history, clinical presentation, and biologic behavior, differentiate it from other leukoplakias that exhibit greater malignant potential. Previous research has demonstrated that the relative risk of oral cancer with smokeless tobacco use is 4.2, about half of the risk from smoking (relative risk = 10 to 15). Mortality data from populations with sustained high-frequency smokeless tobacco use do not support the mistaken prediction of an epidemic of oral cancer with increasing smokeless tobacco use. In fact, the risks of smokeless tobacco use compare so favorably with those of smoking that smokers who switch to smokeless tobacco reduce their risks for all tobacco-related illnesses including oral cancer. Although some criticize this proposal as less than an ideal solution for the nation's smokers, full adoption of this strategy would eventually save over 400,000 lives each year.

Oral epithelial dysplasia and the development of invasive squamous cell carcinoma

Oral epithelial dysplasia, the histopathologic marker of a premalignant disorder of the mouth mucosa, may present clinically as leukoplakia, erythroplakia, or leukoerythroplakia. Its presence in lesions of the oral mucosa is predictive by a variable rate (6.6% to 36%) of transformation to invasive squamous cell carcinoma. We studied the clinical features and microscopic slides of 308 case of oral epithelial dysplasia in our biopsy service and retrospectively evaluated 44 of these with follow-up data for transformation to invasive squamous cell carcinoma. Forty-four patients had follow-up of more than 6 months with a mean follow-up time of 18.4 months. Twenty (45%) were clinically free of disease and 15 (34%) had recurrence of the dysplasia. An additional two cases of lower grades of the disease recurred as carcinoma in situ. Invasive squamous cell carcinoma developed in seven (16%) in a mean transformation time of 33.6 months.

Flow cytometric analysis of nuclear DNA content in oral leukoplakia: relation to clinicopathologic findings

DNA ploidy of 50 biopsy specimens of oral leukoplakia was investigated by flow cytometry, and the results were compared with the clinicopathologic appearances. The aneuploidy rate of the leukoplakias was 17/50 (34%), and the mean DNA index (DI) of the aneuploid lesions was 1.22, with a range from 0.70 to 1.84. The incidence of the aneuploidy was significantly (P < 0.01) higher in nonhomogeneous leukoplakias (11/18) than in homogeneous lesions (6/32). The aneuploidy rate of the severely dysplastic leukoplakias (11/17) was significantly higher than those of the mildly dysplastic (4/22; P < 0.01) and the nondysplastic (2/11; P < 0.02) lesions. A significant (P < 0.01) difference in the aneuploidy rate was also observed between tongue (12/23) and gingival (2/18) leukoplakias.

Oral precancer: preventive and medical approaches to management

Leukoplakias are among the most common potentially malignant oral lesions. Some are idiopathic, others are related to habits such as tobacco and/or alcohol use. Medical management includes reducing or abandoning these habits, increasing the intake of fruit and vegetables in the diet, and possibly the use of active agents. Retinoids, carotenoids and topical cytotoxic agents show promise, and newer therapies are on the horizon.

Biology and chemoprevention of head and neck cancer

Head and neck cancer remains a common cause of mortality and morbidity in the United States and throughout the world. In spite of advances in the management of patients with advanced disease, overall survival in this group remains poor. Furthermore, although cancer mortality is lower in patients with early-stage disease, treatment results in significant morbidity, and these patients also face the risk of developing a second primary tumor. Chemoprevention is an innovative approach to decrease overall cancer morbidity and mortality using substances that are capable of preventing cancer progression. Head and neck cancer is an excellent model for chemoprevention, as its biology is consistent with the two concepts important for the development of chemoprevention strategies: field cancerization and multistep carcinogenesis. Several classes of compounds have been evaluated in chemoprevention trials. The most frequently studied agents, the retinoids, were found frequently to induce remissions in patients with oral leukoplakia. Furthermore, retinoids prevented progression to malignancy in one randomized maintenance study. Other agents, including beta-carotene and vitamin E, have been found also to have activity in the management of oral leukoplakia. However, the clinical role of chemopreventive agents in reducing cancer mortality remains to be defined. Two studies, one in head and neck cancer and one in lung cancer, have shown the ability of retinoids to prevent the development of second primary tumors. Current large randomized trials are defining the effectiveness of these agents in reducing the mortality of aerodigestive tract tumors in individuals at high risk.

Ultrastructural variations and assessment of malignant transformation risk in oral leukoplakia

Oral cancer is the most common malignancy in India, having a well defined precancerous state, leukoplakia. Various follow-up studies have shown that only 4 to 18% of oral leukoplakia lesions subsequently progress into invasive malignancy over a period of time. This study evaluates the potential of electron microscopy in the early detection of malignant changes in leukoplakia. The study revealed that of the 25 leukoplakia lesions examined, 7 showed changes akin to malignancy. Predominant ultrastructural alterations observed were reduplication and discontinuity of the basal lamina, basal cells with pleomorphic and bizarre nuclei containing perichromatin and interchromatin granules, prominent intercellular spaces and poorly formed desmosomes. Since none of these changes were evident under light microscopy the study demonstrates the value of electron microscopy in evaluating oral carcinogenesis. A long term follow-up of such patients is needed to understand the prognostic implications of these ultrastructural variation and how they can be used as a base line for better light microscopic evaluation.

Chemoprevention strategies: the relevance of premalignant and malignant lesions of the upper aerodigestive tract

Patients with premalignant and malignant lesions of the upper aerodigestive tract have historically been the focus of chemoprevention trials within the United States. Experience with this population has formed the basis for trials involving other environmentally induced cancers such as lung and bladder. Given that head and neck cancer patients are at risk for second primary malignancies, prevention strategies can be directed towards decreasing mortality from these metachronous neoplasias. Validity of these strategies, including risk determination, intermediate endpoints, and preventive efficacy of single and combination agents, can be determined. Current limitations in chemoprevention trials involving these patients relate to the sporadic nature of the disease. In fact, the prevalence of oral premalignancy within the United States has not been clearly defined. Individual physician experience with this disease process is limited. Organizational efforts should therefore be directed towards facilitating clinical trials involving dentists, oral surgeons, head and neck surgeons, and other primary health care providers in the community. Risk factors which identify clinically defined normal or premalignant tissue at risk for malignant progression need to be better defined.

Diagnostic significance of nuclear DNA content and nuclear area in oral hyperplasia, dysplasia, and carcinoma

The nuclear DNA content and the nuclear area in hyperplasia, dysplasia, and carcinoma of the oral cavity were quantitatively analyzed by microspectrophotometry. In carcinoma, marked variability of the nuclear DNA content and the nuclear area was found. The mean nuclear DNA content, the variance of the nuclear DNA content, the frequency of cells above tetraploid (4 C), the mean nuclear area, and the variance of nuclear area in hyperplasia and dysplasia were significantly different from these values with carcinoma. In some cases of leukoplakia and verrucous hyperplasia with subsequent malignant formation, the values were beyond the lower limit of carcinoma. The results suggest that the nuclear DNA and the nuclear area are important objective indices for predicting malignant potential of precancerous lesions.

DNA analysis of oral leukoplakia by flow cytometry

DNA ploidy of 19 oral leukoplakias with and without epithelial dysplasia was investigated and the results were compared with 11 normal gingival biopsies, 14 oral benign tumours and 50 oral squamous cell carcinomas. The results suggest a possible relationship between DNA aneuploidy and oral leukoplakias or squamous cell carcinomas, as 32% of the oral leukoplakias and 48% of the oral squamous cell carcinomas were aneuploid although all the normal gingival biopsies and the benign oral tumours examined were diploid. No significant relationship was observed, however, between DNA ploidy and epithelial dysplasia in the leukoplakias.

Evaluation of risk factors in smokeless tobacco-associated oral lesions

Smokeless tobacco (ST) users and nonusers were recruited to evaluate the contribution of various risk factors (ST use, cigarettes, alcohol, and diet) in the development of oral mucosal lesions. Ninety-eight ST users with no lesion, 29 ST users with an oral lesion, and 33 nonusers were enrolled in the study. ST users with lesions, when compared with users with no lesion, were more likely to have used snuff than chewing tobacco (p = 0.01) and to have used more ST (p less than 0.01). Alcohol consumption, dietary intake of beta-carotene, and serum levels of beta-carotene were not related to an increased risk of lesion development. Our findings showed that the only significant risk factor for ST-associated oral lesions was the extent of ST exposure. Of 127 ST users, 29 (22.8%) had an oral lesion at the time of examination. Of these lesions, 23 (79.3%) were hyperkeratotic and 6 (20.7%) were epithelial dysplasia.

The spontaneous regression of cancer. A review of cases from 1900 to 1987

The literature on the spontaneous regression of cancer is reviewed from 1966 to 1987 to update reviews by Everson & Cole and by Boyd. These authors reviewed all cases of spontaneous regression from 1900 to 1965. We then report the entire series from 1900 to 1987. We also attempted to determine what attributions for spontaneous regressions have been reported. Although almost half of the authors failed to speculate or specify a possible cause for the spontaneous regression, the remainder postulated responsible factors such as immunological or endocrine, surgical, necrosis, infection, or operative trauma. The only unorthodox treatment to appear in the literature was the psychological. We conclude that the literature on the spontaneous regression of cancer is still unable to provide unambiguous accounts of the mechanisms operating to affect these regressions.

Smokeless tobacco use and oral epithelial dysplasia

One hundred eight patients with a histologically confirmed diagnosis of epithelial dysplasia of the oral cavity and a prior history of smokeless tobacco (ST) usage were identified. The mean age at time of diagnosis for female patients was almost a decade later than for male patients (63.6 versus 51.2 years). In addition, women were more likely (P = 0.02) to have moderate or severe epithelial dysplasia than men. The two most common locations (buccal mucosa/vestibule and alveolar ridge/gingiva) accounted for 82.4% of all cases. In the 44 cases which specified both ST placement and biopsy site, 90.9% demonstrated epithelial dysplasia at the location used by the patient for holding the ST. When evaluating the histologic severity of epithelial dysplasia, a trend (P = 0.02) toward focal mild or mild was noted among ST users as compared to nonusers. No difference was found in the histologic grade of the lesions associated with either snuff or chewing tobacco.

Oral lichenoid dysplasia: a clinicopathologic analysis

Three women had a diagnosis of oral lichen planus (OLP), which was made on the basis of clinical and histologic features. All three had persistent burning pain associated with large mucosal lesions. Changes in the color (red, red and white, white), configuration, and severity of the lesions were unpredictable and did not correlate well with topical corticosteroid therapy. Only one patient used tobacco (cigarettes)--this patient had recurrent oral candidiasis and was receiving multiple medications. One of the two nonsmokers was a denture wearer with a single episode of candidiasis. After 63, 32, and 56 (mean 50) months, carcinoma developed in all three. In retrospect, the initial biopsy specimens of two patients exhibited lichenoid dysplasia, whereas that of the third showed only lichenoid mucositis. Although speckled erythroplakia was the earliest clinical sign of a classic, nonregressing premalignant lesion, it already signaled the presence of invasive carcinoma. Some early epithelial dysplasias appear to have a robust inflammatory/immunologic response to the antigenically (but as yet not histologically) altered dysplastic epithelium and a high probability of at least temporary resolution. Mucosal erythema of obscure origin displaying spontaneous, usually temporary, partial to complete regression may be common to both purely inflammatory conditions like lichen planus and early epithelial dysplasia. We contend that some, if not most, cases of apparent malignant transformation of OLP likely represent red and white lesions that were dysplastic from their inception but that mimic OLP both clinically and histologically.

Epithelial dysplasia of the oral cavity and lips

Between 1970 and 1986, 1651 biopsy specimens from the oral cavity or lips with a diagnosis of epithelial dysplasia were accessioned by the Medical College of Virginia Oral Pathology Diagnostic Service (Richmond, VA). Of the four histologic grades of epithelial dysplasia (focal mild, mild, moderate, and severe), most of the cases were diagnosed as mild (54.1%) and the fewest (8.1%) were in the severe category. The overall mean age at time of diagnosis was 56.7 years. A predilection for occurrence in males was confirmed, but a lower than expected incidence in blacks was noted. The most common anatomic sites were the buccal mucosa, palate, and floor of mouth. The anatomic areas which were most likely to have a severe epithelial dysplasia were the ventral surface of the tongue and the lip. Patients with dysplasias in more than one site had a slightly higher probability of being diagnosed as either moderate or severe. The cases associated with lichen planus usually were found on the buccal mucosa and demonstrated a shift toward a milder degree of dysplasia.

Prediction of malignant transformation in oral epithelial lesions by image cytometry

The value of image analysis in predicting the malignant potential of oral epithelial lesions showing either hyperplasia or dysplasia was investigated; 5-micron formalin-fixed sections of 16 oral epithelial lesions, of which eight had later transformed to carcinoma and eight had not transformed during a follow-up of 10-15 years were studied. The sections were stained with the azure A-Feulgen reaction for nuclear DNA. In each section 200 nuclei of epithelial cells and 20 nuclei of lymphocytes were assessed; all measurements were made blindly. For each nucleus six features related to shape and amount of stain and six features related to chromatin pattern were assessed. For each feature the mean, SD, and interquartile range were determined and used for linear stepwise discriminant analysis. A model of three variables with the most discriminating power was developed. When the jackknifed classification test was applied using this model, the malignant potential of the lesions that later transformed could be predicted with 87.5% accuracy.

Carcinoma in situ of the upper aerodigestive tract. Incidence, time trends, and follow-up in Rochester, Minnesota, 1935-1984

Epidemiologic analyses of carcinoma in situ (CIS) of the upper aerodigestive tract (UAT) are virtually nonexistent. The current investigation summarizes the total UAT CIS experience of a white, middle class community from 1935 through 1984. Average annual incidence rates varied between genders (3.1 per 100,000 person-years for males versus 0.6 per 100,000 person-years for females), and increased from 1.5 to 3.1 lesions per 100,000 person-years between 1935 and 1964, and 1965 and 1984. Virgin CIS lesions represented 13% of all UAT carcinomas and the vermilion borders of the lips accounted for 42% of all UAT CIS cases. Age-specific incidence rates for males demonstrated a continuous increase with increasing age to 40.5 per 100,000 for males older than 75 years. A clinicopathologic analysis of these lesions is provided.

Epidemiology of carcinoma in situ of the upper aerodigestive tract

Epidemiologic analyses of upper aerodigestive tract (UAT) carcinoma in situ (CIS) are nonexistent, hence only hospital records and surgical pathology resources are available for its descriptive characterization. The National Cancer Institute's Surveillance, Epidemiology and End Results investigation has, however, published valuable raw data pertaining to CIS of the UAT. This information is analyzed here and summarized for the first time, demonstrating the following: a male incidence rate which is four times greater than the female rate (0.8/100,000 males versus 0.2/100,000 females); similar ages at diagnosis for both sexes (62.7 and 60.0 years of age for males and females, respectively); no significant urban/rural incidence differences; that CIS represents 2.8% of all UAT malignancies; that 2.0% of all CIS lesions in humans are found at UAT sites; and that CIS of the uterine cervix is not a good model for CIS of the UAT.

Leukoplakia and carcinoma in situ synchronously associated with invasive oral/oropharyngeal carcinoma in Rochester, Minn., 1935-1984

Previous investigations into the association between oral/oropharyngeal carcinoma and clinical white patches (leukoplakia) have noted that the latter lesion is found adjacent to malignancies in 10% to 100% of all carcinomas of this site. This is an unacceptable variation in results and probably relates more to the referral biases inherent in hospital-based studies than to any other factor. The present population-based study, which is relatively free of selection bias, demonstrates that 62%, 36%, and 18% of invasive carcinomas of the labial vermilion, oral cavity proper, and oropharynx, respectively, have leukoplakia lesions of immediately adjacent mucosal surfaces. Only 7% of invasive carcinomas have juxtaposed carcinoma in situ, whereas another 2% have severe epithelial dysplasia. Mucosal carcinomas associated with leukoplakias appear to be smaller, more mature histologically, and more likely to be only superficially invasive; such carcinomas present with fewer metastases at diagnosis and provide a better prognosis than similar carcinomas not associated with leukoplakia.

An interpretative review of smokeless tobacco research in the United States: Part I

The first part of a two-part series reviewing the published literature of smokeless tobacco in the United States and concomitant health effects associated with its use. This article delineates the current status of its prevalence, behavioral psychosocial factors associated with use, and review of the negative health effects associated with regular use.

Malignant transformation in oral leukoplakia

A retrospective study on the incidence of malignant transformation in oral leukoplakia was performed covering the period from 1970 to 1980. Carcinoma developed in 11 of the 157 patients, and this 7% incidence increased to 8.9% when the same patients were followed prospectively for 6 more years. Dysplasia was found in biopsies from 51 patients (31.8%), and was significantly more frequent in women than men (P less than 0.05). Dysplasia grade and cancer development were related to updated clinical and etiological parameters.

Surgical treatment of premalignant lesions of the oral mucosa

Oral premalignant lesions were treated by surgical excision in 61 patients. Criteria for inclusion in the study were epithelial dysplasia varying from slight to carcinoma in situ, or a non-dysplastic lesion located sublingually or on the tongue. The clinical diagnosis of the treated lesions were: erythroplakia 10, erythroleukoplakia 15, nodular leukoplakia 9, verrucous leukoplakia 9, homogeneous leukoplakia 13, and lichen planus 5. The surgically created defects were closed by direct approximation of the wound edges in 25 patients, transposition by a local mucosal flap in 9, covered with a free mucosal graft in 3, and by a free split skin transplant in 24 patients. The patients have been followed for an average period of 3.9 years after the operation. A recurrence rate of 20% was found, and 3 carcinomas developed in the follow-up period. The importance of using a surgical technique permitting histological examination of the entire lesion was documented by the finding of 4 superficial carcinomas in the excision specimen, undiagnosed in the preoperative biopsy.