Laser management of oral leukoplakias: a follow-up study of 70 patients.

OBJECTIVES/HYPOTHESIS: To assess the efficacy of laser therapy for the management of premalignant oral lesions. STUDY DESIGN: The study group consisted of seventy consecutive laser-treated patients with oral leukoplakia. The microscopic diagnosis included idiopathic focal keratosis, dysplasias of all grades, and verrucous hyperplasia (proliferative verrucous leukoplakia). Thirty-nine patients had some degree of microscopic dysplasia and six demonstrated high-risk proliferative verrucous leukoplakia. The clinical appearances of the lesions were white (homogeneous leukoplakia) in 48, red and white (erythroleukoplakia) in 8, and verrucous in 14. There were 38 men and 32 women in this group. The average age was 63 years (range, 31-90 y). METHODS: Lasers employed were the CO2 and Nd:YAG lasers, and standard laser safety protocols were used. RESULTS: There was no postoperative infection, hemorrhage, or paresthesia Two patients developed pyogenic granulomas in their surgical sites. Fifty-five of 70 patients were followed for more than 6 months; follow-up averaged 32 months (range 6-178 mo). Twenty-nine patients had complete control of their lesions; 19 patients had small recurrences removed with subsequent laser surgeries, leading to control; 2 patients had complete recurrences; and 5 patients developed squamous cell carcinoma at the lesion site. Verrucous lesions had an especially high rate of recurrence (83%), with 9 of 12 ultimately controlled with subsequent surgeries. CONCLUSIONS: Laser surgery of oral leukoplakia is an effective tool in a complete management strategy that includes careful clinical follow-up, patient education to eliminate risk factors and report suspicious lesions, and biopsy of suspicious lesions when appropriate. However, recurrence and progression to cancer remain a risk.

Apoptosis-associated proteins and the development of oral squamous cell carcinoma.

Expression of apoptosis-associated proteins was evaluated in premalignant and malignant oral epithelial lesions, to test the hypothesis that protein regulation of apoptosis may be altered in the development of oral squamous cell carcinoma. Ninety archived paraffin-embedded specimens from 25 patients (two or more sequential biopsies each) and eight control specimens were evaluated in immunohistochemically stained sections for tumor suppressor protein p53, p53 binding protein mdm-2, and apoptosis regulatory proteins Bcl-2, Bcl-X, Bax, and Bak. The initial histologic diagnosis for 17/25 patients was either focal keratosis, mild dysplasia, or moderate dysplasia; the initial diagnosis for the remaining eight patients ranged from severe dysplasia to moderately differentiated squamous cell carcinoma. Thirty of 90 specimens showed positive p53 expression, nine of which were dysplasias. In patients with one or more lesions displaying p53 expression, there was increased intensity of staining with disease progression. Bak was expressed in 57/90 specimens, including 27 dysplasias of various grades. There was also a significantly increased intensity of Bak staining with disease progression, which did not appear to be dependent upon p53 status. Bcl-X was expressed in 73/90 specimens, with staining displayed earlier in premalignant lesions than either p53 or Bak. Ten of 90 specimens were positive for Bcl-2 (all were dysplasias or carcinomas), and only 2/90 specimens were positive for Bax. Eleven of 90 specimens were positive for mdm-2; six of which were also positive for p53. These data show that apoptosis-associated proteins are altered in variable patterns in both premalignant and malignant oral epithelial lesions. p53 and especially Bak and Bcl-X are expressed early; Bax is largely absent; and Bcl-2 and mdm-2 show sporadic expression in the development of oral premalignant and malignant disease.

Cell cycle proteins and the development of oral squamous cell carcinoma.

Expression of cell cycle regulatory proteins was evaluated in premalignant and malignant oral epithelial lesions, to test the hypothesis that protein regulation of the cell cycle may be altered in the development of oral squamous cell carcinoma. Archived paraffin-embedded specimens (n = 90) from 25 patients with recurrent or persistent lesions were evaluated in immunohistochemically stained sections for cell cycle regulatory proteins p53, Rb, Cyclin D1, p27, and p21. The cell cycle was also evaluated by expression of nuclear protein Ki 67. Sections were graded semiquantitatively using a 0-3 + scale to indicate the percentage of positively stained cells. The initial histologic diagnosis for 17/25 patients was either focal keratosis, mild dysplasia, or moderate dysplasia; the initial diagnosis for the remaining eight patients ranged from severe dysplasia to moderately differentiated squamous cell carcinoma. Thirty-three of 90 specimens showed positive p53 expression, 11 of which were dysplasias. Eighty-nine of 90 specimens, from all stages of disease, showed positive Rb expression. Twenty-three of 90 specimens showed positive Cyclin D1 expression, typically in the later stages (carcinoma) of a patient's disease. Eighty-four of 90 specimens showed positive p21 expression; while 55 of 90 specimens were positive for p27. In control mucosa, p27 was highly expressed, while Rb and p21 proteins were expressed at relatively low levels; p53 and Cyclin D1 proteins were largely absent. Generally, staining of p53, Rb, p21, and Ki 67 increased with time in serial biopsies, while p27 showed decreased staining with disease progression. These data show that cell cycle regulatory proteins are altered in both premalignant and malignant disease, and that protein phenotypes are heterogeneous. P53 expression is seen early, and Cyclin D1 expression is seen late in the development of oral premalignant and malignant disease. Expression of p53, Rb, p21 and Ki67 increased, while p27 decreased, with disease progression.

Nd:YAG and CO2 laser therapy of oral mucosal lesions.

OBJECTIVE: Experiences gained in the management of oral mucosal lesions by CO2 and Nd:YAG laser therapy in an outpatient clinic treated over an 80-year period are described. SUMMARY BACKGROUND DATA: Lasers have indications for use in dentistry for incision, excision, and coagulation of intraoral soft tissue. Advances in laser technology have provided delivery systems for site-specific delivery of laser energy with short interaction items on tissue to be ablated. This study retrospectively evaluates a series of clinical case studies. METHODS: Sixty-four patients with a variety of benign oral soft tissue lesions were treated by laser excision. Thirty-five patients were treated by a pulsed fiberoptic delivered Nd:YAG contact laser, and 29 by a continuous free-beam CO2 non-contact laser. The largest group of lesions treated were leukoplakia (39 cases). Other lesions excised and biopsied were lichen planus, squamous papilloma, pyogenic granuloma, focal melanosis, nonhealing traumatic ulceration, hemangioma, and lymphangioma. All patients were followed postoperatively (mean 6.8 months, range 1-36 months). RESULTS: Laser excision was well tolerated by patients with no intraoperative or postoperative adverse effects. All patients healed postsurgically with no loss of function. CONCLUSIONS: CO2 and Nd:YAG lasers are successful surgical options when performing excision of benign intraoral lesions. Advantages of laser therapy include minimal postoperative pain, conservative site-specific minimally invasive surgeries, and elimination of need for sutures.