Oral leukoplakias: to treat or not?

Chemoprevention in oral leukoplakia: challenges and current landscape

Oral potentially malignant disorders have the potential to transform into oral cancer. Oral leukoplakia is a prevalent OPMD with a 9.8% malignant transformation rate. The standard management for OL involves surgical excision, but its efficacy in preventing clinical recurrence and malignant transformation is limited. Therefore, alternative strategies such as chemoprevention modalities have emerged as a promising approach to inhibit the carcinogenesis process. The aim of this review was to identify human studies that investigated the effectiveness of chemopreventive agents in preventing the progression of oral leukoplakia and to provide guidance for future research. Several systemic and topical agents have been evaluated for their potential chemopreventive effects in oral leukoplakia. Systemic agents that have been investigated include vitamin A, lycopene, celecoxib, green tea extract, ZengShengPing, Bowman Birk inhibitor, beta-carotene, curcumin, erlotinib, and metformin. In addition, topical agents tested include bleomycin, isotretinoin, ONYX-015 mouthwash, ketorolac, and dried black raspberry. Despite numerous agents that have already been tested, evidence supporting their effectiveness is limited. To improve the search for an ideal chemopreventive agent for oral leukoplakia, we propose several strategies that can be implemented. Oral leukoplakia chemoprevention presents a promising opportunity for decreasing the incidence of oral cancer. Identifying new chemopreventive agents and biomarkers for predicting treatment response should be a focus of future research.

American Association of Oral and Maxillofacial Surgeon's Position Paper on Oral Mucosal Dysplasia R2

Oral potentially malignant disorders (OPMDs) of the oral mucosa include leukoplakia, erythroplakia, erythroleukoplakia, lichen planus, and oral lichenoid lesions, each with varying incidences of dysplastic disease at the time of presentation and each with observed incidences of malignant transformation over time. The primary goal of the management of dysplasia, therefore, includes their early detection and treatment prior to malignant transformation. The recognition and management of these OPMDs and an understanding of their potential progression to oral squamous cell carcinoma will reduce the morbidity and mortality associated with these lesions with expedient and properly executed treatment strategies that will have a positive effect on patient survival. It is the purpose of this position paper to discuss oral mucosal dysplasia in terms of its nomenclature, epidemiology, types, natural history, and treatment to acquaint clinicians regarding the timing of biopsy, type of biopsy, and follow-up of patients with these lesions of the oral mucosa. This position paper represents a synthesis of existing literature on this topic with the intention of closing gaps in our understanding of oral mucosal dysplasia while also stimulating new thinking to guide clinicians in the proper diagnosis and management of OPMDs. The fifth edition of the World Health Organization classification of head and neck tumors published in 2022 represents new information regarding this topic and a construct for this position paper.

Recurrence and malignant transformation rates of high grade oral epithelial dysplasia over a 10 year follow up period and the influence of surgical intervention, size of excision biopsy and marginal clearance in a UK regional maxillofacial surgery unit

OBJECTIVES

To determine the overall recurrence rate (RR) and malignant transformation rate (MTR) of high grade oral mucosal epithelial dysplasias (HGOED).

MATERIALS & METHODS

A clinicopathological review of records of patients diagnosed with a unifocal HGOED between 2004 and 2016 on incisional biopsy who then underwent excision. The mean duration of follow-up was 47.7 months (±29.9 SD).

RESULTS

Full demographic, historical and histopathological data were available for 120 patients. Six were lost to follow-up after excisional biopsy. Invasive squamous cell carcinoma (SCC) was present in 19 (18.3%) excisions. HGOED affected the lateral and ventral tongue in 58% of patients. Fourteen (11.7%) were not treated surgically but kept under surveillance. The overall RR was 34.7% (33 patients) and MTR 17.8% (17 patients). Four of the 14 (28.6%) patients who had not had the HGOED excised developed SCC, by contrast to the 13 of the 106 (12.3%) who had been treated. RR was significantly associated with positive excision margins (p = 0.007; OR = 3.6) and a clinical presentation of erythroplakia (p = 0.023; OR = 1.5). MTR was significantly associated with age (p = 0.034), clinical appearance (p = 0.030), site (p = 0.007), treatment received (p = 0.012) and positive excision margins (p = 0.007). The mean time for recurrence to develop was 62 months (±31.5 SD) (range 22-144 months), that for malignant transformation was 50 months (±32.5 SD) (range 8-97 months).

CONCLUSION

Patients with HGOED require follow-up for at least 10 years after treatment. Younger age, homogeneous clinical appearance, complete excision, a larger excision specimen and clear margins all improve prognosis.

Oral potentially malignant disorders: clinical diagnosis and current screening aids: a narrative review

Around 300 000 patients are estimated to have oral cancer worldwide annually, and the incidence is higher in South Asian countries. In 2005, at the Congress of WHO, the term potentially malignant disorder (PMD)/lesion was suggested as a replacement for premalignant oral lesions and conditions. PMDs are those lesions of the oral mucosa that are at an increased risk of malignant transformation compared with the healthy mucosa. PMDs consist of leukoplakia, erythroplakia, oral lichen planus, oral submucous fibrosis, and other miscellaneous lesions. A literature search was performed using PubMed, Scopus, and Web of Science without any language restrictions. There is no standardized method for identifying a site for biopsy and various methods such as toluidine blue stain, methylene blue, Lugol's iodine, and chemiluminescence have been proposed in the literature. Despite easy access to the oral cavity, there has been significant mortality associated with oral cancer as they are often diagnosed late because of the inability of healthcare professionals to identify them at early premalignant states. This article aims to provide healthcare professionals with the knowledge to identify potentially malignant disorders and to aid them in biopsy site identification.

Correlation analysis of oral lesion sizes by various standardized criteria

OBJECTIVE

Requirements of an NCI contract examining a novel treatment for leukoplakia were to compare standard bi-dimensional measurement of oral lesions to examine for correlation with Response Evaluation Criteria in Solid Tumors (RECIST) criteria, and to examine the feasibility of digital image analysis for automated measurements.

STUDY DESIGN

Retrospective review.

METHODS

We examined 13 patients by bi-dimensional measurement and compared these measurements to 1) RECIST criteria, 2) scalar digital measurements using a standardized measuring device within the photograph, and 3) pixel number.

RESULTS

RECIST criteria correlated (r-squared=0.8535, p<0.0001) with bi-dimensional measurements. Digitized measures in photographs correlated with bi-dimensional measurements (r-squared=0.6661, p=0.0007), but were time consuming. There was minimal to no correlation between pixel number in Adobe Photoshop and the other measures.

CONCLUSION

Bi-dimensional measurement of oral leukoplakia and RECIST criteria are highly correlated. Digital photography measurements, though highly correlative, are very cumbersome. We recommend bi-dimensional or longest length measurement and a simple photograph as standard of documentation for leukoplakia lesions.

Immunohistochemical evaluation of oral epithelial dysplasia using cyclin-D1, p27 and p63 expression as predictors of malignant transformation

OBJECTIVE

To evaluate the degree of expression of cyclin-D1, p27 and p63 in mild, moderate and severe dysplasia using immunohistochemical evaluation in order to illustrate their prognostic value and attempt to propose a molecular grading system for oral epithelial dysplasia.

MATERIALS AND METHODS

The analysis included thirty cases of mild, moderate and severe dysplasia from Department of Oral and Maxillofacial Pathology, Saveetha Dental College, Chennai after a critical review of the Hematoxylin and Eosin (H and E) stained sections. They were subjected to immunohistochemical evaluation using the markers cyclin-D1, p27 and p63. The assessment of the expression based on staining intensity and distribution of immunohistochemical staining of the various markers was analyzed followed by statistical analysis.

RESULTS

A highly significant increase in the expression of cyclin-D1 (P < 0.000) and p63 (P < 0.001) and a moderately significant decrease in the expression of p27 (P < 0.012) with the increasing severity of dysplasia was observed in our study.

CONCLUSIONS

The result of our research affirms the fact that the increase in the expression of markers of cell cycle regulators such as cyclin D1, decrease in the expression of cell cycle inhibitors like p27 and increased expression of p63 in parallel with the increasing severity of dysplasia, emphasizes the use of immunohistochemical markers cyclin D1, p27 and p63 as prognostic markers for better understanding the behaviour of these potentially malignant disorders aiming towards proposing a molecular grading system for oral epithelial dysplasia to enable timely management prior to their possible malignant transformation.

Are we able to reduce the mortality and morbidity of oral cancer; some considerations

Oral cancer makes up 1%-2% of all cancers that may arise in the body. The majority of oral cancers consists of squamous cell carcinomas. Oral cancer carries a considerable mortality rate, being mainly dependent on the stage of the disease at admission. Worldwide some 50% of the patients with oral cancer present with advanced disease. There are several ways of trying to diagnose oral cancer in a lower tumor stage, being 1) mass screening or screening in selected patients, 2) reduction of patients’ delay, and 3) reduction of doctors’ delay. Oral cancer population-based screening (“mass screening”) programs do not meet the guidelines for a successful outcome. There may be some benefit when focusing on high-risk groups, such as heavy smokers and heavy drinkers. Reported reasons for patients’ delay range from fear of a diagnosis of cancer, limited accessibility of primary health care, to unawareness of the possibility of malignant oral diseases. Apparently, information campaigns in news programs and TV have little effect on patients’ delay. Mouth self-examination may have some value in reducing patients’ delay. Doctors’ delay includes dentists’ delay and diagnostic delay caused by other medical and dental health care professionals. Doctors’ delay may vary from almost zero days up to more than six months. Usually, morbidity of cancer treatment is measured by quality of life (QoL) questionnaires. In the past decades this topic has drawn a lot of attention worldwide. It is a challenge to decrease the morbidity that is associated with the various treatment modalities that are used in oral cancer without substantially compromising the survival rate. Smoking cessation contributes to reducing the risk of oral cancers, with a 50% reduction in risk within five years. Indeed, risk factor reduction seems to be the most effective tool in an attempt to decrease the morbidity and mortality of oral cancer.

Key words:Oral cancer, early diagnosis, quality of life.

Two members of the SIBLING family of proteins, DSPP and BSP, may predict the transition of oral epithelial dysplasia to oral squamous cell carcinoma

BACKGROUND

: Patients with oral premalignant lesions (OPL) present with oral squamous cell carcinomas (OSCC) at a much higher rate than the general population. There are currently no useful markers that indicate specifically which OPLs are most likely to progress. Three small integrin binding ligands N-linked glycoprotein (SIBLING) family proteins, bone sialoprotein (BSP), osteopontin (OPN), and dentin sialophosphoprotein (DSPP), have been shown to be up-regulated in many cancers, including OSCC. The status of SIBLING expression in OPLs and their correlation to transition to oral cancer are unknown.

METHODS

: Sixty archival surgical biopsies of dysplastic OPLs were evaluated by immunohistochemistry for expression of BSP, DSPP, and OPN and correlated with local transformation to OSCC at sites adjacent to surgically removed dysplastic OPL.

RESULTS

: The OPL patient population was representative of previous studies with 20% progressing to OSCC, and no correlation between degree of dysplasia and progression. Eighty-seven percent were positive for at least 1 SIBLING protein. OPN expression had no correlation with progression. The BSP+/DSPP- expression pattern however correlated with decreased transformation to OSCC (point prevalence = 0%; 95% confidence interval [CI], 0-20.6), whereas the BSP-/DSPP+ pattern was associated with more frequent progression (point prevalence = 77.8%; 95%CI, 47.8-95.4). Incrementally higher expression scores (0 to 3) of BSP and DSPP were also associated with increased predictive values (odds ratio, 25.53; 95% CI, 2.14-304.7 and 10.13; 95% CI, 2.0-50.0, respectively, for each increment).

CONCLUSIONS

: BSP and DSPP are excellent candidate markers for successful OPL surgical intervention and may be predictors of OPL-OSCC progression. Cancer 2010. (c) 2010 American Cancer Society.

Potentially malignant disorders of the oral and oropharyngeal mucosa; terminology, classification and present concepts of management

In a recently held WHO workshop it has been recommended to abandon the distinction between potentially malignant lesions and potentially malignant conditions and to use the term potentially malignant disorders instead. Of these disorders, leukoplakia and erythroplakia are the most common ones. These diagnoses are still defined by exclusion of other known white or red lesions. In spite of tremendous progress in the field of molecular biology there is yet no single marker that reliably enables to predict malignant transformation in an individual patient. The general advice is to excise or laser any oral of oropharyngeal leukoplakia/erythroplakia, if feasible, irrespective of the presence or absence of dysplasia. Nevertheless, it is actually unknown whether such removal truly prevents the possible development of a squamous cell carcinoma. At present, oral lichen planus seems to be accepted in the literature as being a potentially malignant disorder, although the risk of malignant transformation is lower than in leukoplakia. There are no means to prevent such event. The efficacy of follow-up of oral lichen planus is questionable. Finally, brief attention has been paid to oral submucous fibrosis, actinic cheilitis, some inherited cancer syndromes and immunodeficiency in relation to cancer predisposition.

Squamous cell carcinoma of the oral cavity: a case series analysis of clinical presentation and histological grading of 1,425 cases from Iraq

Peoples in Iraq face a mixture of health hazards associated with poverty. Oral cancer is a major public health issue worldwide; it remains a highly lethal and disfiguring disease. It is primarily a disease of epithelial origin. A total of 1,425 cases of histologically diagnosed squamous cell carcinoma collected from the main centers of pathology in Iraq were analyzed according to age, sex, site, patient complaints at the time of presentation, and histological grading. Patients at their fifth decade of life were the most commonly affected with a male-to-female ratio of 2:1. The lower lip was the most commonly affected site followed by the tongue. The most common clinical complain was ulceration and swelling. More than 70% of the cases were well-differentiated squamous cell carcinoma. Oral cancer is increasingly seen as a major health problem-In line with general trend in the region, the need for interprofessional health care delivery approaches for reducing oral cancer mortality and improving patient's quality of life.

MGMT expression in oral precancerous and cancerous lesions: Correlation with progression, nodal metastasis and poor prognosis

Alkylation of DNA at the O(6) position of guanine is a critical step in the induction of mutations by carcinogenic and chemotherapeutic alkylating agents. O(6)-methylguanine-DNA methyltransferase (MGMT) is an enzyme that removes mutagenic adducts from the O(6) position of guanine, thereby protecting the genome against guanine to adenine transitions. We hypothesized that alteration in MGMT expression might occur in early stages of development of oral cancer and be associated with disease progression. Immunohistochemical analysis of MGMT expression was carried out in 107 oral squamous cell carcinomas (OSCCs), 78 oral precancerous lesions (OPLs) (58 hyperplasias and 20 dysplasias) and 30 histologically normal oral tissues and correlated with clinicopathological parameters as well as major risk factors. Decreased MGMT expression was observed as early as in hyperplasia (p=0.003; Odd's Ratio (OR)=5.0). Significant loss of MGMT expression was observed from hyperplasia to dysplasia (p=0.034; OR=4.0). Loss of MGMT expression was associated with late clinical stage of OSCCs (p=0.027, OR=2.0) and nodal metastasis (p=0.031, OR=2.5). Decreased MGMT expression was associated with smokeless tobacco (ST) consumption in patients with OPLs (p=0.017, OR=3.6) and OSCCs (p=0.031, OR=2.8). Significant association was also observed between loss of MGMT expression and poor prognosis of OSCC patients (p=0.02; OR=5.2). The decreased MGMT expression in OPLs suggested that deregulation of MGMT expression is an early event in the development of oral cancer. In OSCCs, its correlation with late clinical stage, and nodal metastasis suggests association with aggressive tumor behavior and cancer progression, underscoring its potential as a candidate predictive marker for nodal metastasis and disease prognosis. Correlation of loss of MGMT expression with ST consumption underscored its significance in ST-associated oral carcinogenesis.

Long-term treatment outcome of oral premalignant lesions

The purpose of the present retrospective study was to learn the long-term outcome of oral premalignant lesions, leukoplakia and erythroplakia, with or without surgical intervention and to relate the outcome to factors supposed to be significant for malignant development including clinical type, demarcation, size, site, presence of epithelial dysplasia, smoking and surgery. A total of 269 lesions in 236 patients were included. Ninety-four lesions were surgically removed, 39 lesions (41%) being homogenous and 46 (49%) non-homogenous leukoplakias whereas nine (5%) were erythroplakias. Seventy-three percent of the lesions were associated with tobacco habits. The mean size of the lesions was 486 mm(2), and 71% of the lesions showed a degree of epithelial dysplasia. After excision the defects were closed primarily by transposition of mucosal flaps or they were covered by free mucosal or skin grafts. A few defects were left for secondary healing. After surgical treatment the patients were followed (mean 6.8 yrs, range 1.5-18.6 yrs), and new biopsies taken in case of recurrences. One hundred and seventy five lesions had no surgical intervention, 149 lesions (85%) being homogenous and 20 (11%) non-homogenous leukoplakias, and 6 (3%) erythroplakias. Eighty-one percent of the lesions were associated with smoking. The mean size of the lesions was 503 mm(2) and 21 of the lesions (12%) exhibited epithelial dysplasia. Sixty-five lesions were not biopsied. These patients were also followed (mean 5.5 yrs, range 1.1-20.2 yrs), and biopsies taken in case of changes indicative of malignant development. All patients were encouraged to quit smoking and candidal infections were treated. The possible role of different variables for malignant development was estimated by means of logistic regression analysis. Following surgical treatment 11 lesions (12%) developed carcinoma after a mean follow-up period of 7.5 yrs. Non-homogenous leukoplakia accounted for the highest frequency of malignant development, i.e. 20%, whereas 3% of the homogenous leukoplakias developed carcinomas. Surgically treated lesions with slight, moderate, severe and no epithelial dysplasia developed carcinoma with similar frequencies, i.e. 9-11%. Without surgical intervention 16% of the 175 lesions disappeared whereas seven lesions (4%) developed carcinoma after a mean observation period of 6.6 yrs. The highest frequency of malignant development (15%) was seen for non-homogenous leukoplakias, this figure being 3% for homogenous leukoplakias. Fourteen percent of lesions with slight epithelial dysplasia developed malignancy and 2% of lesions with no dysplasia showed malignant transformation. Logistic regression analysis showed a seven times increased risk (OR = 7.0) of non-homogenous leukoplakia for malignant development as compared with homogenous leukoplakia and a 5.4 times increased risk for malignant development for lesions with a size exceeding 200 mm(2). No other examined variables including presence of any degree of epithelial dysplasia, site, demarcation, smoking and surgical intervention were statistically significant factors for malignant development.

Oral premalignancy: new methods of detection and treatment

Oral carcinogenesis proceeds through a stepwise accumulation of genetic damage over time. Because the oral cavity is easy to examine and risk factors for oral cancer are known, there is great opportunity to improve patient outcomes through diagnosis and treatment of pre-malignant lesions before the development of invasive oral carcinoma. This review provides a summary of developments in detection and diagnosis of oral premalignant lesions and innovative approaches to management of early oral neoplasia. These technological and therapeutic advances are much needed to improve the poor outcomes associated with oral cancer due to our inability to diagnose and treat this disease at an early, curable stage.

Effective management of smoking in an oral dysplasia clinic in London

BACKGROUND

Precancerous lesions precede the development of oral cancer; of several clinical types the most common is leukoplakia. The risk factors include tobacco and excess alcohol use and diets low in antioxidants. Studies concerning the management of risk factors related to oral precancer are meager.

OBJECTIVES

We investigated the effectiveness of smoking cessation at a dysplasia clinic among patients followed up for at least for 12 months.

METHODS

Data from case notes relating to 180 patients with white and red patches of oral mucosa (excluding other benign disorders confirmed by biopsy findings) attending a dysplasia clinic at a teaching hospital in London and seen by one consultant between 1993 and 2003 were transcribed. Effect of referring to a smoker's clinic to receive specialist help was evaluated against brief advice given at the dysplasia clinic +/- medications.

RESULTS

The mean age at the first visit was 48.5 years (+/-12.5), 65% were male, and 88% were white European. One hundred and sixty-two patients (90%) had used tobacco and 83% were current smokers. Of the smokers 95% had smoked over 10 years, the majority smoking over 10 cigarettes per day. Nine were alcohol misusers including two binge drinkers. One hundred and forty-six were diagnosed with oral leukoplakia, 16 with non-homogeneous types (speckled or nodular). Three patients were diagnosed with an erythroplakia. Nineteen per cent exhibited the presence of dysplasia and one subject had in situ carcinoma. Five patients in the sample quit smoking prior to arrival in the dysplasia clinic. Twenty-seven cases (20%) with oral leukoplakia quit smoking while registered as a patient at the dysplasia clinic: 17 of 100 subjects quit with brief advice +/- medications and 10 of 30 following referral to the smoker's clinic. The difference between the two groups was significant for point prevalence abstinence at the last visit to the clinic (minimum 12 months follow up). Out of a total of 180 precancer cases managed in the dysplasia clinic (mean follow up 4.2 years) three patients subsequently developed invasive carcinoma during follow up.

CONCLUSIONS

Smoking cessation needs to be an integral component of management of cases attending a dysplasia clinic and referring to smoker's clinics could help to improve the effectiveness of managing patients with oral precancer to quit smoking.

Diagnosis and management of suspicious lesions of the oral cavity

Oral lesions associated with premalignant changes and malignancy present in diverse ways. This article discusses the clinical characteristics of such lesions enabling clinicians to identify classical features.Additionally, an effort is made to familiarize clinicians with the significance of red and white lesions, especially those having a high index of suspicion for oral cancer, and to alert clinicians when a biopsy is mandatory.

[New knowledge on the diagnosis of oral leukoplakia]

INTRODUCTION

There have been many discussions and debates in the literature over appropriate criteria for diagnosing oral leukoplakia and for predicting its prognosis.

CLINICAL ASPECTS

In general, two clinical variants of leukoplakia are being recognised: the homogeneous and non-homogeneous type. Clinical subdivisions of leukoplakia in these two types can be used for cases in which no biopsy is available.

DIAGNOSTIC PROCEDURES

A 2-4 week interval to observe a possible regression or disappearance of a white lesion, after elimination of possible causative factors, seems to be a fully acceptable period of time before taking a biopsy. Taking a biopsy in homogeneous leukoplakia and especially non-homogeneous leukoplakia should be a standard rule. It is recommended that the histologic report should include a statement on absence or presence of epithelial dysplasia and an assessment of its severity. This recommendation was made in order to provide a classification and staging system reflecting the size and histopathologic findings.

The influence of resection and aneuploidy on mortality in oral leukoplakia

BACKGROUND

Although the standard treatment of oral leukoplakia ranges from watchful waiting to complete resection, the value of these approaches is unknown.

METHODS

We studied the relations among resection, ploidy status, and death from cancer in 103 patients with diploid dysplastic oral leukoplakia, 20 patients with tetraploid lesions, and 27 patients with aneuploid lesions. Data on cancer-specific mortality and treatment were obtained from the Cancer Registry of Norway, Statistics Norway, and chart reviews.

RESULTS

Primary oral carcinoma developed in 47 of the 150 patients with leukoplakia (31 percent)--5 with diploid, 16 with tetraploid, and 26 with aneuploid leukoplakia--during a mean follow-up of 80 months (range, 4 to 237). The margin status of the initial leukoplakia resection had no relation to the development of oral cancer (P=0.95). Twenty-six of the 47 patients in whom cancer developed (4 with prior tetraploid and 22 with prior aneuploid lesions) had recurrences (55 percent); the recurrences were more frequently multiple and distant (within the oral cavity) among patients with aneuploid lesions than among those with tetraploid or diploid lesions. All 47 patients underwent a standard regimen of surgery and radiation, followed by chemotherapy in the 26 with recurrent cancer. Only patients with aneuploid leukoplakia died of oral cancer; the five-year rate of death from cancer was 72 percent. Aneuploidy-related first carcinomas were diagnosed at a more advanced stage than were carcinomas originating from diploid or tetraploid leukoplakia (P=0.03) and were more likely to be lethal regardless of the stage.

CONCLUSIONS

Complete resection of aneuploid leukoplakia does not reduce the high risk of aggressive carcinoma and death from oral cancer.

Impact of genomic instability in risk assessment and chemoprevention of oral premalignancies

Head-and-neck cancer is a disfiguring disease with increasing incidence rates even in young people, whose exposure to known risk factors is limited. This emphasizes the importance of early identification, on an individual basis, of precursor lesions that will develop into carcinomas. The clinical value of identifying individuals at high risk of oral cancer is emphasized by the fact that these patients are likely to benefit from available chemopreventive measures, largely without adverse effects.

Oral leukoplakia: a proposal for uniform reporting

Leukoplakia is the most common precancerous lesion of the oral mucosa. In order to promote uniform reporting of management results, including the event of malignant transformation, recommendations have been made for the various definitions and terminologies, including the application of a certainty factor with which the diagnosis of oral leukoplakia has been established. For reporting purposes there seems to be no rationale for distinguishing "tobacco-associated" leukoplakias from non-tobaccco-associated, so-called idiopathic leukoplakias. The recommendation has been made to use a classification and staging system in which the size and the histopathologic findings are reflected. At present, there seems to be no justification to give a weighting factor to the oral subsite of leukoplakias.

Suprabasal p53 immunoexpression is strongly associated with high grade dysplasia and risk for malignant transformation in potentially malignant oral lesions from Northern Ireland

AIMS

No good predictive marker for the malignant transformation of potentially malignant oral lesions (PMOLs) is currently available. This study re-evaluated the value of p53 immunoexpression to predict malignant transformation of PMOLs after discounting possible confounding factors.

METHODS

PMOLs from 18 patients who showed progression to carcinoma, 16 of the respective carcinomas, and PMOLs from 18 matched controls were evaluated by immunohistochemistry (IHC) for p53 expression. A mouse monoclonal antibody that detects wild-type and mutant forms of human p53 was used. The p53 immunostaining pattern was also correlated with the degree of dysplasia.

RESULTS

Suprabasal p53 staining was significantly associated with high grades of dysplasia (p < 0.01). The specificity and positive predictive value (PPV) for malignant transformation of suprabasal p53 staining were superior to the assessment of dysplasia, but sensitivity was inferior. All carcinomas derived from PMOLs with suprabasal p53 showed strong p53 immunostaining. However, the absence of suprabasal p53 staining and/or dysplastic changes did not preclude malignant transformation in a considerable proportion of PMOLs.

CONCLUSIONS

This study confirms and extends previous findings that suprabasal p53 immunoexpression has a high PPV for malignant transformation of PMOLs and can be used as a specific marker for lesions that are at high risk for malignant transformation. The absence of suprabasal p53 staining (that is, absence of, or basal, p53 staining) is non-informative for prognostic purposes. Because of its limited sensitivity, p53 IHC is not a substitute for the assessment of dysplasia in the evaluation of PMOLs. Instead, p53 IHC emerges as a clinically useful supplement of histopathological assessment in the prognosis of PMOLs.

Expression of bcl-2 and bax in chewing tobacco-induced oral cancers and oral lesions from India

Deregulation of oncogenes and tumor suppressor genes involved in apoptosis has been associated with tumor development and progression. To investigate the involvement of apoptosis regulating proteins in oral cancer in Indian patients, primarily associated with chewing tobacco habits, immunohistochemical expression of bcl-2 and bax was examined in 63 oral squamous cell carcinomas, and 31 putative premalignant lesions. Our studies revealed overexpression of tumor specific cytoplasmic bcl-2 in 56% and bax in 43% oral cancers. The oral cancers in the Indian patients are preceded by premalignant oral lesions; hence oral lesions were examined for bcl-2 and bax expression. We observed aberrant expression of bcl-2 in 16% oral lesions comprising leukoplakias and SMF and bax in 55% oral lesions. We have already reported, p53 expression in these oral cancers and lesions. It was noteworthy that 30% oral cancers demonstrated a p53+bcl2+ pattern, and 14% samples exhibited p53+bcl2+bax+ pattern. However, none of the oral lesions showed concurrent deregulation of p53 and bcl-2 or all the three genes. Interestingly 45% oral lesions were p53-bax+ as compared to 18% oral cancers; while 39% oral lesions were bcl2-bax+ as compared to 14% oral cancers, indicating overexpression of bax in oral lesions, in the absence of p53 and bcl-2 proteins. Significant correlation was observed between positive nodal status and bcl2+ (p=0.047) and p53+bcl-2+ (p=0.01) in oral cancers. Kaplan Meier survival analysis showed significantly (p=0.059) higher survival in patients with p53- oral tumors than with p53+ tumors. Our studies thus indicate frequent overexpression of apoptosis regulators bcl-2, bax and p53 proteins in oral cancers, and a subset of oral lesions, representing early events in oral car-cinogenesis. The aberrant bcl-2 expression and loss of p53 function observed, may play an important role in the tumorigenesis of oral cancers by allowing escape from apoptosis and enabling additional genetic alterations to accrue.

Impact of localized treatment in reducing risk of progression of low-grade oral dysplasia: molecular evidence of incomplete resection

Currently, there is no consensus on the appropriate treatment for low-grade oral dysplasia. This is mainly due to the difficulty in predicting outcome for this heterogeneous group of lesions. In this study, we constructed a detailed clinical history of 66 mild and moderate dysplasias in order to determine how treatment affected outcome, and to evaluate the effect of treatment on lesions with different genetic profiles, which are defined by patterns of loss of heterozygosity (LOH) associated with low, intermediate and high risk of progression [Clin. Cancer Res., 6, 357-62, 2000]. The results showed that although treatment guided by clinical removal of leukoplakia reduced cancer progression risk in all three risk groups, the amount of reduction in our study group did not reach statistical significance. To assess whether completeness of lesion removal was a major factor in recurrence, repeat biopsies at the primary sites were analyzed for persistent LOH status on chromosomes 3p, 4q, 8p, 9p, 11q, 13q and 17p. Strikingly, eight of 17 cases judged clinically removed contained the same molecular clones in the initial and subsequent biopsies, suggesting incomplete removal. When molecular information was included in the assessment of lesion removal, treatment significantly reduced the risk of progression for cases with intermediate (P=0.043) and high risk (P=0.001) genetic profiles, but not cases with low-risk profiles. A 9.1-fold decrease in progression risk was observed for those with high-risk profile. Altogether, these data suggest the use of molecular profiles to guide the treatment of low-grade dysplasia. Our data also suggest that currently an inadequate margin may in part be responsible for the high rate of recurrence, especially in high-risk lesions.

Increased genetic damage in oral leukoplakia from high risk sites: potential impact on staging and clinical management

BACKGROUND

Two staging systems for oral leukoplakias have been proposed to better predict prognosis. Although one system includes site as an independent determinant, its use is controversial.

METHODS

Recent studies have shown that loss of heterozygosity (LOH) in oral premalignancies is associated with risk of progression. The authors analyzed 127 oral dysplasias for LOH on 3 chromosome arms (3p, 9p, and 17p). The lesions included 71 from the floor of mouth, ventrolateral tongue, and soft palate complex (designated high risk [HR] sites) and 56 from the rest of the oral cavity (low risk [LR] sites).

RESULTS

Dysplasias from HR sites contained significantly higher LOH frequencies than LR sites (percentage with any loss, P = 0.0004; percentage with multiple losses, P = 0.0001; percentage loss on each of the arms, P < 0.05). Loss on 3p and/or 9p, a pattern associated with a 24-fold increased risk of progression (Rosin MP, Cheng X, Poh C, Lam WL, Huang Y, Lovas J, et al. Use of allelic loss to predict malignant risk for low-grade oral epithelial dysplasia. Clin Cancer Res 2000;6:357-62) was more frequent among HR lesions (P = 0.0005). Loss of heterozygosity frequencies were elevated at HR sites among both genders and among smokers and nonsmokers. For different histologic groups, LOH frequencies were elevated for HR sites in mild dysplasias (P < 0.05) and moderate dysplasias (marginal significance, P = 0.06), but not in severe dysplasias/carcinoma in situ.

CONCLUSIONS

Anatomic location of mild and moderate oral dysplasias in Western populations may be an important diagnostic indicator because lesions at HR sites have a greater tendency to include genetic alterations associated with elevated risk of progression.

Topical application of vitamin A to oral leukoplakia: A clinical case series

BACKGROUND

Due to the possibility of malignant transformation of oral leukoplakia, these lesions must be assessed and managed closely and, if not resolved, must be reassessed on a regular basis.

METHODS

This study evaluated the use of topical 0.05% vitamin A (tretinoin) acid gel for the treatment of oral leukoplakia. Tretinoin was applied topically 4 times a day for the management of nonmalignant oral white lesions in 26 patients. The clinical response was evaluated in all patients and posttreatment biopsies were performed in ten patients.

RESULTS

The mean age of the patients at the time of diagnosis was 62 years. Of the 26 patients, 50% were tobacco users. Patients were followed for a mean of 23 months. Approximately 27% of the patients had a complete clinical remission. Recurrence of leukoplakia was observed in approximately 40% of patients in whom complete clinical remission occurred if topical applications were discontinued. A 50% reduction in the clinical grade of leukoplakia from a mean of 2.8 to 1.4 on a scale ranging from 0 (no leukoplakia) to 4 (speckled leukoplakia) was observed. When the pretreatment and posttreatment biopsies from 10 patients were evaluated, no change in the mean histologic grade (between mild and moderate dysplasia) was noted; however, some reduction in the histologic grade was noted in 3 of these patients (30%).

CONCLUSIONS

The use of topical vitamin A acid showed a limited effect in controlling oral leukoplakia. Further studies are needed to establish the appropriate indication, efficacy, and best choice for chemoprevention agents. Close follow-up of all patients with oral leukoplakia is required.

Oral cancer in the UK: to screen or not to screen

Although oral squamous cell carcinoma accounts for only a small proportion of malignant neoplasms in the UK, oral cancer incidence and mortality rates have been rising in recent years. The natural history of oral cancer is not adequately understood at present and there is very little information about the epidemiology of precancerous lesions in the UK. There are also insufficient data to provide firm evidence that the percentage of cases arising de novo is greater in the UK and the Western world as compared to the Indian subcontinent. Screening for oral cancer by visual examination is simple, inexpensive and causes little discomfort; however, there is no evidence for the effectiveness of screening for oral cancer either in reducing mortality from the disease or in reducing the incidence of invasive disease by detection and treatment of precancerous lesions. There is currently insufficient evidence to recommend population screening for oral cancer in the UK. Measures aimed at primary prevention of the disease may be a more feasible method of disease control at present.