| The Use of surgical lasers in the Therapy of Oral Precancerous states |
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L. Gáspár (1), P. Vágó (2) Abstract The experience with 1089 laser interventions of oral precancerosis is surveyed. Different surgical lasers (CO2, Nd YAG and CO2+Nd YAG) were used. The differentiated technique elaborated on by the authors ensures, besides the safe removal of the tissues involved, the greatest preservation of oral functions. In precancerosis, coagulation was performed by a 5 W defocused CO2 laser beam: in verrucosus cases, vaporisation was done by using a 10 to 15 W focused beam: in erosive cases, excision was performed using a 20 to 25 W focused beam. The Nd YAG and CO2+Nd YAG interventions were performed with defocused and focused beam in the cases of blood clothing disorders. Thus, it became possible to remove only the pathologic tissues. Wound healing leaves minimal scarring and the therapeutic result is favourable , from both functional (nourishment, speech, mimic) and aesthetic points of view. Following one laser treatment in 1007 of 1089 patients (92.4%), a symptom-free condition could be observed. Postoperative pain and oedema are minimal: the majority of the patients are capable of resuming work by the second postoperative day. It is established that one of the most important oral surgical indications of the CO2 laser treatment is represented by the presence of leukoplakias. Key words: surgical lasers, precancerous states, oral cavity Introduction The cancer mortality rate in Hungary is especially high: it ranks as the second leading cause of death. During the past 25 years, the cancer mortality rate in males increased by 150%. and a considerable, threefold increase took place in the number of malignancies of the oral cavity. In 1995, every seventh male cancer death was due to tumours of the oral cavity. Considerable efforts have been made all over the world to achieve early diagnosis of precancerous conditions. It is an ever-urgent necessity to introduce a program of regular oral cancer screening. The early diagnosis of precancerous conditions and tumours of the oral cavity will detect a greater number of patients whose management will emphatically raise questions regarding the use of the laser beam. The favourable experience obtained with the laser beam will certainly help to establish its superiority over a few traditional procedures, at least until new and more effective methods appear. Currently, substantial knowledge is accumulating based on the laser therapy of oral precancerosis for assessing the opportunities of laser treatment and critically evaluating its effectiveness. The literature data on oral leukoplakia and his own research results are surveyed by Bánoczy 1 . She stresses the importance of the elimination of etiologic factors and suggests conservative therapy that, in case of failure, is followed by surgical approach. Regular follow-up is essential the significance of dysplasia is emphasised. After conservative therapy (with vitamin A), Schettler and Horch 22 and Panders et al. 3 observed a recurrence rate of 40 to 55%. Following surgical incision, relapse was seen by Silverman et al., 4 Vedtofte et al., 5 and Mincer et al. 6 in 20 to 33% of the cases. Cryotherapy suppressed the relapse rate below 20%. 7-14 Following removal of the leukoplakia with the CO 2 laser, a less than 10% relapse rate was reported on by Frame et al., 15 Frame, 16 Burian and Höfler, 17 Roodenburg, 18 Rhys Evans et al., 19 Tuffin and Carruth, 20 and Horch et al. 21 Such initial favourable results, on smaller patient samples, were also described by us in previous publications. 22-26 Regarding the laser surgical treatment of the precancerosis, three basic methods are mentioned in the literature: a. Treatments with defocused beam 19,20 The interventions can be performed by CO2, Nd YAG and combi (CO2+Nd YAG) lasers, both by a handpiece and by an operation microscope adjusted with a micromanipulator. Our own experience and the data of the literature provide unambiguous proof that oral precancerosis can be effectively treated by laser surgery. Complications are few, and the aesthetic results are favourable. This paper is intended to summarise our experience gained in this field thus far.
Material and methods In our department, a Scalpel-1, Tungsram TLS 62, Sharplan 1040, CO 2 laser, Medi-YAG 100 Nd YAG laser, Combo 5050 Lasermatic CO2+Nd YAG laser were used. Between January 1, 1987 and December 31, 1993, 1089 oral precancerosis were removed with laser surgery (Table 1.). 692 of them were leukoplakia and 195 were of cheilitis chronica.There were 755 male and 334 female patients, with a mean age of 51,7 years (range:19 to 94 years). The precancerosis most frequently occurred on the lower lip (33.8%) and on the tongue (12.4%). In 73.5% a single, in 19.1% double, and in 7.4% a multiple occurrence was observed (Table 2.). Fifty-two percent of the patients were treated by previous conservative therapy, 31.4% conservative and some sort of surgical treatment, while 16.6% had untreated lesions. Twenty of those operated on suffered from clotting disturbances ( 8 patients with thrombocytopenia, 12 with hypothrombinemia) and 68 were assigned to risk groups for other reasons:
The majority of the patients who underwent laser surgery presented for stomatologic consultation performing regional tasks as well, with dental or stomatosurgical reference. Prior to surgery, a tissue sample was taken for histological examination. The operations were performed under local anaesthesia (2% lidocaine, 0,001% adrenaline). During surgery for simple leukoplakia, the lesion was removed with 1 mm , in verrucosus case with 2 mm , and in ulcerous case at least with 3 mm of healthy tissue. Three types of laser operations were performed :
(Table 2., Table 3.) In the first two types, the tissues are touched only by the laser beam: in the third one, the excision is made by applying continuous traction to the pathologic area. The minor vessels are coagulated by the laser beam during cutting: vessels with a diameter larger than 1 mm ( CO2) or 2- 3 mm ( Nd YAG and combi) are identified and severed between the ligatures.
Results Surgery could be performed on a practically bloodless wound surface. In the case of vaporisation, the laser beam immediately coagulated the vessels less than 1 mm (CO2) or 2- 3 mm (NdYAG and combi) in diameter : in the case of excision, the major vessels exposed on the wound surface were recognised and cut between the ligatures when necessary. The twenty haemophilic patients were also operated on without any bleeding. The application of the laser beam ensures ablastic operation. In our patient population, the embedding histological examination-with the clinical picture of erosive leukoplakia-verified carcinoma in situ from the laser-excised tissue in 6 cases. Since, in the preoperative histology, we diagnosed erosive leukoplakia, we did not extend the degree of the laser excision. During follow-up 2-7 years postintervention, close observation revealed neither local recurrence nor regional metastasis. Oncological evaluation of our other operations would be a futile exercise, owing to the oncopathologic character of the lesions. During coagulation and vaporisation, the tissues were touched only by the laser beam. During excision, only the continuous traction of the pathologic area was performed using conventional instruments. Healthy tissues were not tugged or traumatized:no pathogens or their toxins or tumour cells were transmitted by this "no-touch" technique onto the healthy regions. This tissue-saving technique results also from the fact that the coagulation and vaporisation performed by the laser beam allows greater selectivity than any other existing method, removing only the pathologic tissues while sparing the healthy structures. In the case of cutting the CO2 laser knife results in a thermodamaged zone of 300 microns in thickness: thus the thermal damage of the healthy area is minimal. The aseptic applicability results partly from the fact that the laser beam immediately destroys the pathogens on the incised surface, after lasing, the wound surfaces are covered by a protective layer of coagulated proteins, which provides favourable conditions for the epithelialization of the occasionally large areas concerned. Following the removal of 1089 precancerosis, inflammatory phenomena developed in 16 cases, but patients recovered with targeted antibiotic treatment. Except for 16 inflammations, 50 suture-united wounds, and 36 other intervention, no oedema developed in the postoperative period (table 4.). Following coagulation and vaporisation, regardless of the size and site of the lased surface, no moderate (requiring correction due to functional or aesthetic causes) or minimal (only minimal aesthetic fault) scare tissue developed in 811 cases (74.5%). Regarding the degree of postoperative pain, the evaluation was based on patients , reports. Of the 1089 patients operated on, 225 (20.6%) required analgesics on the day of the operation. One day later, only 74 (6.8%) patients required analgesics.On the operative day, the patients did not observe swallowing or nourishing disturbance: they were able to take oral nourishment by themselves. As to the speed and quality of wound healing, the epithelialization terminated by the third week in case of coagulation, and by the fourth week when vaporisation and excision were performed. Lesions of smaller surfaces recovered sooner. The multicentric leukoplakias were removed usually in one sitting: their healing was more prolonged, varying with their extent, taking up to the fourth or fifth postoperative week. When evaluating the patients after a follow-up of 2-7 years, we found that out of 1089 patients, 1007 were symptom free (92.4%) (Table 7.). Recurrence developed in 82 cases and 4 patient died due to other (cardiovascular) disease. Of the 82 recurrences, 50 developed after surgery of verrucosus and erosive leukoplakia (recurrence rate 7.3%), 15 lichen oris (recurrence rate 34.1%), 11 cheilitis chronica (5.7%). In the relapsing cases, a second lasing was performed that resulted in a symptom-free condition (in 61 of the 82 cases), while in 21 cases according to the operative field, simple precancerosis appeared.
Discussion Laser surgery ensures, besides the safe removal of the precancerosis, the considerable maintenance of oral functions. The fact that we can adhere strictly to removal of the pathologic tissues only and that the wound healing takes place with minimal scarring, assures favourable reception of the procedure from both functional (nourishment, speech, mimics) and aesthetic points of view. This goal is achieved by all three individual CO2 laser surgical interventions (coagulation, vaporisation, excision) or, occasionally, by their combined application. Thus, the radicality required by the severity of the lesion can be counterbalanced by the maximal potential preservation of the healthy tissues. Favourable aesthetics and functional results were seen in cases of CO2 laser coagulation and vaporisation. The cutting procedure is favourable by CO2 laser beam. Due to its 2- 4 mm depth of effect the Nd YAG laser ensures better coagulation than the carbon dioxide one, it can also close larger vessels although larger healthy tissues get damaged. The Nd YAG laser is highly favourable in the treatment of haemophilic patients and major vascular lesions. The combined laser (CO2+Nd YAG) application makes it possible to achieve proper coagulative and cutting effect corresponding to the properties of the structures. In more haemophilic cases wider coagulation is made mostly with Nd YAG beam and less CO2 is applied while in interventions requiring less coagulation the CO2 laser outweighs the use of Nd YAG.. By combined application the coagulation and cutting effect could be adjusted to any desirable extent. Laser therapy represents significant savings for the national economy. The purchase of the laser equipment requires a single investment, but further maintenance or material costs are unremarkable. The instrumental demand of the laser operations is minor as a rule, not even sutures are necessary. Since the results in a high response rate after only the first treatment, the manifold travelling by patients can be avoided and their absence from work is minimal. One day after surgery, 90% of those operated on are already capable of resuming work. We consider it a remarkable advantage of lasing that the initial treatment ensures a response equal to two, three, or several cryotreatments. Based on the experience gained so far we are of the opinion that one of the most important oral surgical indications of the laser beam is the therapy of oral precancerosis.
References 1. Bánóczy, J.: Oral Leukoplakia. Budapest. Ed:Akadémiai Kiadó.1982. pp.1-140. Address: Dr L. Gáspár Department of Oral and Maxillofacial Surgery Gáspár L., Vágó P.
Tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table1.
Table 2.
Table 3.
Table 5.
Table 6.
Table 7.
Table 8.
Dr Paul J.W.Stoelinga, Editor in Chief Budapest, 31 August, 1996. Dear Professor Stoelinga, Enclosed you will find a manuscript entitled : The use of surgical lasers in the therapy of oral precancerous states. This manuscript is the part of our study on the summarisation of our 10 years clinical experience on laser surgery. I hope you will consider it for publication in Int.J. Oral and Maxillofacial Surgery. Your sincerely Lajos Gáspár associated professor, DDS, PhD Central Military Hospital, Medical Laser Center |
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