Interventional laser surgery: an effective surgical and diagnostic tool in oral precancer management

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

The CO₂ laser was invented in 1963 by Kumar Patel. Since the early 1970s, CO₂ laser has proved to be an effective method of treatment for patients with several types of oral lesions, including early squamous cell carcinoma.

Laser surgery of oral premalignant disorders is an effective tool in a complete management strategy which includes careful clinical follow-up, patient education to eliminate risk factors, reporting and biopsying of suspicious lesions and any other significant lesions. However, in a number of patients, recurrence and progression to malignancy remains a risk. CO₂ laser resection has become the preferred treatment for small oral and oropharyngeal carcinomas. Laser resection does not require reconstructive surgery. There is minimal scarring and thus, optimum functional results can be expected.

New and improved applications of laser surgery in the treatment of oral and maxillofacial/head and neck disorders are being explored. As more surgeons become experienced in the use of lasers and as our knowledge of the capabilities and advantages of this tool expands, lasers may play a significant role in the management of different pathologies.

Complications following interventional laser surgery for oral cancer and precancerous lesions

Interventional carbon dioxide laser surgery is the preferred method to treat oral precancerous lesions and early invasive squamous cell carcinomas (SCCs). Little is known, however, about the complications that patients experience after such treatment. We retrospectively reviewed the hospital records of 82 patients with new dysplastic oral lesions or early invasive oral SCCs treated by laser surgery in the maxillofacial unit at Newcastle General Hospital. The most common postoperative complications were pain for more than two weeks after operation (n=28), bleeding (n=4), difficulties with speech (n=5), paraesthesia of the lingual nerve (n=17), difficulty swallowing (n=2), obstructive swelling of the submandibular gland (n=22), and tethering of the tongue (n=10). Overall, 78% of patients had one or more complication. In the absence of randomised controlled trials, this study provides the best available evidence for complication rates following interventional surgery. In addition to aiding in the preoperative counselling of patients, the data will help to inform and advise patients particularly during the immediate postoperative period.

Er,CR:YSGG lasers induce fewer dysplastic-like epithelial artefacts than CO2 lasers: an in vivo experimental study on oral mucosa

Our aim was to assess wounds made by lasers (CO(2) and Er,Cr:YSGG) for their epithelial architectural changes and width of damage. We allocated 60 Sprague-Dawley(®) rats into groups: glossectomy by CO(2) laser at 3 different wattages (n=10 in each); glossectomy by Er,Cr:YSGG laser at two different emissions (n=10 in each), and a control group (n=10). Histological examination assessed both prevalence and site of thermal artefacts for each group. Both lasers (CO(2) and Er,Cr:YSGG) caused the same type of cytological artefacts. The 3W Er,Cr:YSGG laser produced the fewest cytological artefacts/specimen, and was significantly different from the other experimental groups: 3W CO(2) laser (95% CI=0.8 to 1.0); the 6W CO(2) laser (95% CI=0.1 to 2.0) and the 10W CO(2) laser (95% CI=1.1 to 3.0). CO(2) lasers (3-10W) generate epithelial damage that can simulate dysplastic changes with cytological atypia that affects mainly the basal and suprabasal layers. Irradiation with Er,CR:YSGG laser (2-4W) produces significantly fewer cellular artefacts and less epithelial damage, which may be potentially useful for biopsy of oral mucosa.

CO2 laser of oral dysplasia: clinicopathological features of recurrence and malignant transformation

The use of the CO(2) laser in the management of oral dysplastic lesions has become a more common practice. Very few studies have evaluated recurrence, residual disease malignant transformation, and overall outcome in patients undergoing such a procedure. In this prospective study, a total of 123 oral dysplastic lesions from 77 consecutive patients were treated with the CO(2) laser (resection and/or ablation). The average age was 58 ± 4.8 years. The patients' recovery was uneventful and no complications were reported. Comparisons with the clinical and histopathological features and rate of recurrence as well as malignant transformation were made. The patients were followed-up for a mean of 6.4 years, and biopsies taken in case of changes suggestive of malignant development. Homogenous leukoplakias were identified in 31 patients, non-homogenous leukoplakias in 34 patients, whereas 12 patients had erythroplakias. Ex- and life-long smokers formed 88.3% of the recruited patients. While people who currently smoke and drink formed 55.8% of the cohort. Erythroplakias were solely identified in heavy life-long smokers. The most common identified primary anatomical locations were the lateral border of tongue, floor of mouth, and buccal mucosa. Moderate dysplasia was identified in 42 patients while 18 patients had severe dysplasia. Laser resection margins in selected cases (68 patients) were clear in 53 and showed mild-moderate dysplasia in the involved margins. The rate of recurrence had no significant association with the location but the severity of epithelial dysplasia. The rate of first recurrence after laser surgery was approximately 19.5%. Malignant transformation was observed in eight patients (10.4%), in the tongue and the floor of mouth. Recurrence and malignant transformation was mainly identified in erythroplakias and non-homogenous leukoplakias. Laser resection/ablation is recommended for oral dysplasia to prevent not only recurrence and malignant transformation but also postoperative oral dysfunction encountered by other conventional modalities.

Management of oral carcinoma: benefits of early precancerous intervention

Management of oral precancerous lesions remains polarised between interventional surgery and conservative treatment. We have previously shown the efficacy of carbon dioxide laser excision for both diagnosis and treatment of oral precancerous lesions. The aim of this study was to review the clinicopathological details of a group of patients in whom pre-existing but occult invasive carcinoma was diagnosed histopathologically in specimens excised by laser. We retrospectively reviewed 169 patients who attended the Maxillofacial Dysplasia Clinic at Newcastle General Hospital with single, new oral premalignant lesions over a 5-year period (2004-2008). They were all treated by laser excision of lesions that were confirmed to be dysplastic from examination of preoperative incisional biopsy specimens. There was a significant correlation between the results of diagnostic incisional, and laser excision, biopsy specimens (p < 0.01), but 15 patients had signs of occult invasive carcinoma in the excision specimens (9%). In all cases the carcinomas were completely excised by the laser. Carbon dioxide laser excision is not only an effective treatment of precancerous lesions, but also facilitates early diagnosis and management of oral carcinoma at a stage when it is otherwise clinically undetectable.

Treatment of oral leukoplakia with carbon dioxide and potassium-titanyl-phosphate lasers: a comparison

PURPOSE

To determine whether the treatment of oral leukoplakia with potassium-titanyl-phosphate (KTP) lasers versus CO(2) lasers results in lower recurrence rates.

MATERIALS AND METHODS

Retrospective data were collected from the records of 30 patients (mean age 75.6 years) with 35 primary oral leukoplakia who had their lesions ablated by KTP laser, and 45 patients (mean age 59.9 years) with 59 primary oral leukoplakia who had CO(2) laser treatment. The recurrence rates of lesions between these 2 groups was then compared.

RESULTS

A statistically significant (P = .049) reduction in recurrence rates for those patients treated with KTP lasers versus CO(2) lasers was found.

CONCLUSION

The use of KTP lasers for the treatment of oral leukoplakia may result in lower recurrence rates than when using CO(2) lasers.

Expression of heat shock proteins, Hsp70 and Hsp25, in the rat gingiva after irradiation with a CO2 laser in coagulation mode

BACKGROUND AND OBJECTIVE

The therapeutic rationale of low-energy pulsed CO(2) laser coagulation mode has not been clarified yet. We conducted this study to characterize the effect of low-energy pulsed CO(2) laser coagulation mode irradiation of the rat gingiva in terms of the expression of heat shock proteins.

MATERIAL AND METHODS

Laser irradiation was achieved with the parameters of 5 W, 600 mus pulse duration, and fluence of 326 J/cm(2). The gingiva dissected at different times after irradiation was processed for immunohistochemical examination of the expression of the heat shock proteins, Hsp70 and Hsp25.

RESULTS

One hour after irradiation, the epithelial keratinocytes facing the laser wound exhibited an overexpression of Hsp70 in their nucleus. The connective tissue cells facing the laser wound, which included fibroblasts and capillary endothelial cells, showed de novo expression of Hsp70 at 3 h post-irradiation, the level of which peaked at 1 d and thereafter decreased. An enhanced and/or de novo expression of Hsp25 in the connective tissue cells facing the laser wound became evident at 3 h after irradiation, and after 1 d the Hsp25-expressing cells increased in number and spread over the wound as wound repair progressed. There was a temporospatial difference in the expression pattern between Hsp70 and Hsp25, with only a few cells appearing to co-express both heat shock proteins.

CONCLUSION

The CO(2) laser treatment in coagulation mode produced the expression of heat shock proteins, and the findings suggest that while Hsp70 mainly conferred cell protection, Hsp25 was involved in the progress of wound repair as well as cell protection.

Photodynamic therapy for head and neck dysplasia and cancer

OBJECTIVE

To determine the response of dysplasia, carcinoma in situ (CIS), and T1 carcinoma of the oral cavity and larynx to photodynamic therapy with porfimer sodium.

DESIGN

Prospective trial.

SETTING

A National Cancer Institute-designated cancer institute.

PATIENTS

Patients with primary or recurrent moderate to severe oral or laryngeal dysplasia, CIS, or T1N0 carcinoma.

INTERVENTION

Porfimer sodium, 2 mg/kg of body weight, was injected intravenously 48 hours before treatment. Light at 630 nm for photosensitizer activation was delivered from an argon laser or diode laser using lens or cylindrical diffuser fibers. The light dose was 50 J/cm(2) for dysplasia and CIS and 75 J/cm(2) for carcinoma.

MAIN OUTCOME MEASURES

Response was evaluated at 1 week and at 1 month and then at 3-month intervals thereafter. Response options were complete (CR), partial (PR), and no (NR) response. Posttreatment biopsies were performed in all patients with persistent and recurrent visible lesions.

RESULTS

Thirty patients were enrolled, and 26 were evaluable. Mean follow-up was 15 months (range, 7-52 months). Twenty-four patients had a CR, 1 had a PR, and 1 had NR. Three patients with oral dysplasia with an initial CR experienced recurrence in the treatment field. All the patients with NR, a PR, or recurrence after an initial CR underwent salvage treatment. Temporary morbidities included edema, pain, hoarseness, and skin phototoxicity.

CONCLUSION

Photodynamic therapy with porfimer sodium is an effective treatment alternative, with no permanent sequelae, for oral and laryngeal dysplasia and early carcinoma.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00530088.

Genomic imbalances in precancerous tissues signal oral cancer risk

Oral cancer develops through a series of histopathological stages: through mild (low grade), moderate, and severe (high grade) dysplasia to carcinoma in situ and then invasive disease. Early detection of those oral premalignant lesions (OPLs) that will develop into invasive tumors is necessary to improve the poor prognosis of oral cancer. Because no tools exist for delineating progression risk in low grade oral lesions, we cannot determine which of these cases require aggressive intervention. We undertook whole genome analysis by tiling-path array comparative genomic hybridization for a rare panel of early and late stage OPLs (n = 62), all of which had extensive longitudinal follow up (>10 years). Genome profiles for oral squamous cell carcinomas (n = 24) were generated for comparison. Parallel analysis of genome alterations and clinical parameters was performed to identify features associated with disease progression. Genome alterations in low grade dysplasias progressing to invasive disease more closely resembled those observed for later stage disease than they did those observed for non-progressing low grade dysplasias. This was despite the histopathological similarity between progressing and non-progressing cases. Strikingly, unbiased computational analysis of genomic alteration data correctly classified nearly all progressing low grade dysplasia cases. Our data demonstrate that high resolution genomic analysis can be used to evaluate progression risk in low grade OPLs, a marked improvement over present histopathological approaches which cannot delineate progression risk. Taken together, our data suggest that whole genome technologies could be used in management strategies for patients presenting with precancerous oral lesions.

Factors affecting carbon dioxide laser treatment for oral precancer: a patient cohort study

BACKGROUND

Although the benefits of CO(2) laser surgery in oral precancer management have been evaluated, little consideration has been given to the factors which may influence treatment outcome, especially amongst patients developing recurrence or malignant transformation.

STUDY DESIGN

Seventy eight patients (51 males, 27 females; mean age 57.8 years) undergoing CO(2) laser excision of single, new dysplastic oral precancer lesions (OPLs) were followed up for a minimum of 2 years and the influence of clinico-pathological parameters, socio-demographic factors and the presence or absence of residual dysplasia in excision margins upon clinical outcome were examined.

RESULTS

Seventy three percent of patients were smokers and 78% consumed alcohol regularly. The majority of lesions were leukoplakias arising in the floor of mouth and ventro-lateral tongue and moderate or severe dysplasia accounted for 86% of histopathological diagnoses. Patient follow up ranged from 24 to 119 months (mean 58 months). Sixty four percent of patients were disease free at most recent clinical follow up, whilst 32% developed local recurrent dysplasia or new site dysplasia with 4% developing oral squamous cell carcinoma (but at sites distinct from their initial OPL). Excision margins were clear in 55% of cases, but 19% showed mild, 21% moderate and 5% severe dysplasia on histopathological examination. No statistically significant associations were seen between patients' age, gender, lesion appearance, site of origin, histopathological grading, presence of dysplasia in resection margins, or alcohol consumption and clinical outcome. Smokers, however, were at significantly higher risk of dysplasia recurrence compared to ex-smokers or non-smokers (P = 0.04).

CONCLUSIONS

In the absence of agreed treatment protocols for OPLs, we recommend CO(2) laser surgery as an effective treatment modality offering precise lesion excision, full histopathological assessment, minimal post-operative morbidity and a 64% disease free clinical outcome. Regular patient follow up is encouraged due to the persistence of field cancerisation effects.

Multiplexed immunobead-based assay for detection of oral cancer protein biomarkers in saliva

OBJECTIVE

For clinical applications of biomarkers, there is a need for multiplex assays using high throughput platforms. The objective of this study was to determine the efficacy of Luminex Multianalyte Profiling (xMAP) technology for measurement of salivary proteins and to evaluate whether multiplex assays are as effective as single-plex assays and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The average levels of interleukin-8 (IL-8) from the single-plex assay were 3313.2 +/- 3759.8 pg ml(-1) [oral squamous cell carcinoma (OSCC), n = 20] and 1061.7 +/- 1978.8 pg ml(-1) (control, n = 20). The IL-1beta average levels from the single-plex assay were 945.2 +/- 1134.8 pg ml(-1) (OSCC, n = 20) and 314.2 +/- 444.8 pg ml(-1) (control, n = 20). The average levels of IL-8 from the multiplex assay were 2834.9 +/- 3385.6 pg ml(-1) (OSCC, n = 20) and 947.3 +/- 2036.8 pg ml(-1) (control, n = 20). The IL-1beta average levels from the multiplex assay were 1013.5 +/- 1221.1 pg ml(-1) (OSCC, n = 20) and 376.3 +/- 576.3 pg ml(-1) (control, n = 20). The correlation coefficient between Luminex and ELISA assay for IL-8 (n = 19) and IL-1beta (n = 19) was 0.91 and 0.84, respectively.

CONCLUSION

Luminex xMAP single-plex and multiplex assays are as effective as ELISA assays for quantification of proteins in saliva. Both IL-8 and IL-1beta were expressed at significantly higher levels in OSCC subjects than in the matched healthy control subjects.

Potential use of quantitative tissue phenotype to predict malignant risk for oral premalignant lesions

The importance of early diagnosis in improving mortality and morbidity rates of oral squamous cell carcinoma (SCC) has long been recognized. However, a major challenge for early diagnosis is our limited ability to differentiate oral premalignant lesions (OPL) at high risk of progressing into invasive SCC from those at low risk. We investigated the potential of quantitative tissue phenotype (QTP), measured by high-resolution image analysis, to identify severe dysplasia/carcinoma in situ (CIS; known to have an increased risk of progression) and to predict progression to cancer within hyperplasia or mild/moderate dysplasia. We generated a nuclear phenotype score (NPS), a combination of five nuclear morphometric features that best discriminate 4,027 "normal" nuclei (selected from 29 normal oral biopsies) from 4,298 "abnormal" nuclei (selected from 30 SCC biopsies). This NPS was then determined for a set of 69 OPLs. Severe dysplasia/CIS showed a significant increase in NPS compared with hyperplasia or mild/moderate dysplasia. However, within the latter group, elevated NPS was strongly associated with the presence of high-risk loss of heterozygosity (LOH) patterns. There was a statistical difference between NPS of hyperplasia or mild/moderate dysplasia that progressed to cancer and those that did not. Individuals with a high NPS had a 10-fold increase in relative risk of progression. In the multivariate Cox model, LOH and NPS together were the strongest predictors for cancer development. These data suggest that QTP could be used to identify lesions that require molecular evaluation and should be integrated with such approaches to facilitate the identification of hyperplasia or mild/moderate dysplasia OPLs at high risk of progression.

Management of potentially malignant disorders: evidence and critique

At a workshop coordinated by the WHO Collaborating Centre of Oral Cancer and Precancer in the United Kingdom, issues related to management of patients affected by oral leukoplakia were discussed by an expert group. The consensus views of the working group are presented here. Although removal of a lesion still seems to be the predominant method of treatment by the majority of relevant health care professionals, no randomized controlled trials have been undertaken to test the hypothesis that excision either by scalpel or laser greatly influences the potential for later malignant transformation within the oral mucosa of an affected individual. Results of observational studies indicate that, although surgery may have a beneficial effect, this is not likely to reduce the risk of later recurrence nor malignant transformation at the same or another site. Medical measures that lessen the size, extent or histopathological features of dysplasia within leukoplakia likewise presently do not seem to be of particular promise, as relapse or later malignant transformation can occur, and there is a risk of adverse effects, particularly with systemic agents (which themselves may be contra-indicated in some individuals). While the risk of malignant transformation, and the development of further potentially malignant disease may theoretically be reduced by cessation of risk activities, such as tobacco usage and alcohol consumption, there remain no good studies that demonstrate that such measures significantly reduce such events.

Effects of active non-smoking programmes on smoking behaviour in oral precancer patients

Smoking is the commonest risk factor for oral cancer and precancer. The objective of this study was to characterize smoking behaviour and attitude in a cohort of oral precancer patients in Newcastle upon Tyne, UK, and to determine changes in behaviour during diagnosis, treatment and follow-up. Twenty-seven consecutive, smoking patients with dysplastic oral lesions were recruited to the study and a detailed smoking history obtained, quantifying types and numbers of cigarettes smoked, length of smoking history, and changes in smoking behaviour during treatment episodes and long-term follow-up. All patients underwent an interventional management protocol comprising risk-factor education, histopathological diagnosis by incisional biopsy and laser excision of lesions. Patients were followed up for 5 years. Whilst there was a significant decrease in the number of cigarettes smoked at patients' most recent follow-up compared with initial presentation (p<0.001), 74% continued to smoke. Patients received advice from a smoking cessation adviser on support available to them from the local NHS (National Health Service) Stop Smoking services. Six out of 10 patients who set a 'quit date' and attended a programme had quit at the 4-week follow-up but only 5 remained non-smokers. Smoking remains a considerable problem in oral precancer patients even after interventional treatment, with the risk of further precancerous lesions and malignant transformation.

Cyclin A activity predicts clinical outcome in oral precancer and cancer

Accurate, predictive assessment of the behaviour of oral cancers and precancers remains elusive. Increasing dysregulation of cell proliferation is a feature of carcinogenesis, and alterations in cyclin proteins regulating cell cycle progression are involved in enhanced cell proliferation. The authors of the present study have previously demonstrated increased proliferative activity in oral dysplastic lesions and poorly differentiated carcinomas, and hypothesize that cell proliferation can be used as a predictive agent in clinical management. In this preliminary study, immunohistochemical quantification of cyclin A expression was carried out for 33 excised oral lesions (ranging from mild dysplasia to invasive squamous cell carcinoma, SCC). Clinical outcome was determined as: no disease after 2 years follow-up, persistent disease, or further disease presentation. Labelling Indices (LIs) ranged from 5.5 to 32.1%, and whilst a trend to increased labelling in increasingly dysplastic and neoplastic tissue was seen, this was not statistically significant (P=0.06). High LIs were related to poor clinical outcome (P=0.003), suggesting a definite role for cyclin A measurement as a predictive tool in clinical management.

Cancerisation within the oral cavity: the use of 'field mapping biopsies' in clinical management

Field cancerisation within the oral cavity risks multiple primary tumour development. Whilst multi-focal disease may ultimately affect up to 24% of oral cancer patients, a particular management problem is encountered with those patients presenting with pan-oral dysplasia. In an attempt to characterise the extent of dysplasia and to quantify the risk of malignant change, examination under anaesthesia (EUA) and multiple, 'field mapping biopsies' were carried out for 16 consecutive patients presenting with pan-oral disease. Seventy lesions, predominantly homogenous leukoplakias, were biopsied primarily showing hyperkeratosis or mild dysplasia histologically. More significant dysplasia was seen to affect the faucial pillars, floor of mouth and ventral tongue. Interventional CO(2) laser surgery was used to excise 11 severely dysplastic lesions in six patients. Field mapping appears effective in the initial identification and treatment of the most significant areas of dysplasia in patients with multi-focal precancer. Longitudinal, multi-centre trials are now required.

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.

The use of CO2 laser in the treatment of oral white patches: outcomes and factors affecting recurrence

Laser therapy has been a favoured treatment regime for oral leukoplakia since the mid 1980s. There is no information in the literature regarding factors affecting outcomes in patients with oral leukoplakia. Forty-three patients (mean age 60.3+/-13.6 years) with 73 primary oral leukoplakia were assessed for outcome and factors affecting survival. Dysplastic lesions were found in the majority of patients. The male to female ratio was 1.7:1 with 74% ex- or current smokers, 27% consuming alcohol and 31% continuing to smoke after treatment. The mean observation time was 47.2+/-28.2 months (range 2-102 months). Disease-free survival was 55.4% at 3 years that dropped to 33.9% after 5 years. The malignant transformation rate was 7.3%. No significant prognostic factors were found on univariate analysis but alcohol consumption (P=0.034) and previous malignancy (P=0.018) were found to be significant prognostic indicators using multivariate analysis. Continuation to smoke approached significance (P=0.061). Similar disease-free survival and malignant transformation rates with minimal complications were found as compared to the literature. Recommendations for minimizing recurrence are presented. Long-term follow up and removal of aetiological factors, such as smoking and alcohol, are advised.

The results of CO2 laser surgery in patients with oral leukoplakia: a 25 year follow up

Oral leukoplakia is an important premalignant lesion of the oral mucosa. We treat this lesion prophylactically with CO2 laser evaporation. In the period from 1976 to 2001, a group of 200 patients with 282 oral leukoplakias were treated by CO2 laser evaporation. In a follow up period of 1-219 months (mean 52), 251 treated leukoplakias (89.0%) did not show a recurrence. Twenty eight (9.9%) local recurrences were observed in 5 to 168 months after treatment. Three (1.1%) squamous cell carcinoma, occurred in the treated area respectively 7, 17 and 19 month after CO2 laser evaporation. This large study with a long follow up shows that laser treatment is a good prophylactic treatment for oral leukoplakia.

Lasers in contemporary oral and maxillofacial surgery

The practice of oral and maxillofacial surgery has included the use of lasers since the 1960s. Over the past few decades, the use of lasers among oral and maxillofacial surgeons has grown dramatically. Their evolution within the specialty not only has enhanced current surgical options for treatment, but also contributed to a variety of new procedures that are now commonplace in oral and maxillofacial surgery. The management of patients with sleep apnea, temporomandibular joint derangements, dental implants, premalignant lesions, and posttraumatic facial scarring has improved significantly with the advent of laser surgery. As the number of laser systems grows and their technology becomes more advanced, a thorough understanding regarding the principles of their use is paramount to providing safe and effective patient care.