Oral leukoplakia is a white patch or plaque on the mucous membranes of the mouth that cannot be characterized as any other definable lesion. The World Health Organization classifies it as an oral potentially malignant disorder because it carries a risk of transforming into oral squamous cell carcinoma, a type of mouth cancer. The transformation rate is variable, ranging from less than 1% to over 30% depending on the lesion’s features, making proper management necessary.
Assessing the Lesion and Determining Risk
Accurate diagnosis and determination of malignant risk rely heavily on a biopsy. This procedure involves taking a tissue sample to exclude other conditions that present as a white patch, such as candidiasis or lichen planus, and to assess the internal cell structure. For smaller lesions, an excisional biopsy may remove the entire patch, while larger lesions require an incisional biopsy taken from the most suspicious area.
The tissue sample is examined histologically for epithelial dysplasia, the most important factor in predicting malignant transformation. Dysplasia is a disturbance in normal cellular differentiation and is graded as mild, moderate, or severe. Severe dysplasia carries a high risk of malignant change, while lesions with no or only mild dysplasia have a much lower risk. The risk assessment, based on the histological grade, lesion size, and clinical appearance—such as being non-homogeneous or speckled—directs the urgency and type of treatment.
Initial Conservative Management and Monitoring
For non-dysplastic lesions or those showing only mild dysplasia, the initial strategy involves a conservative approach focused on eliminating known risk factors. The most significant action is the cessation of all tobacco use and the reduction or elimination of heavy alcohol consumption. Tobacco and alcohol are strongly associated with leukoplakia progression, and their removal can sometimes lead to the spontaneous regression of the lesion.
Conservative management also includes addressing local irritants contributing to the white patch, such as a sharp tooth edge or a poorly fitting dental prosthetic. Once irritants are removed, the patient is placed on an active surveillance protocol. During this period, which may last several months, a specialist closely monitors the lesion. Follow-up appointments are typically scheduled every three to six months to check for changes in size, texture, or color. If the lesion persists or progresses, a repeat biopsy may be necessary to reassess the dysplasia grade.
Surgical and Physical Removal Techniques
Surgical removal physically eliminates the abnormal tissue and is used for lesions showing moderate or severe dysplasia. Traditional scalpel excision involves removing the lesion with a margin of two to five millimeters of surrounding healthy tissue to ensure complete removal and achieve clear margins. The advantage of scalpel excision is that it provides an intact specimen for comprehensive histological examination, allowing pathologists to confirm dysplasia severity.
Several physical techniques offer alternatives to the scalpel, often preferred for reduced bleeding and lower patient discomfort. Carbon dioxide (CO2) laser surgery is widely used and can be performed as either an excision, which cuts out the tissue, or an ablation, which vaporizes the tissue. Laser excision provides a sample for pathology, but laser ablation is faster and results in less scarring, though it destroys the tissue, preventing definitive post-operative histological assessment.
Cryotherapy involves applying extreme cold, usually liquid nitrogen, to destroy abnormal cells by freezing them. Electrocautery uses heat generated by an electrical current to burn away the lesion. Both methods are effective, but like laser ablation, they destroy the tissue. Therefore, an incisional biopsy must be performed beforehand to confirm the diagnosis and dysplasia grade. Recurrence rates following surgical intervention remain a challenge, ranging from approximately 25% to nearly 50%.
Adjunctive Pharmacological Treatments
Pharmacological treatments are used as adjunctive therapy, especially for patients with widespread lesions or those unsuitable for surgery. The most studied agents are retinoids, synthetic derivatives of Vitamin A, such as isotretinoin. Retinoids influence the growth and differentiation of epithelial cells, promoting maturation toward a normal appearance.
Systemic retinoids, taken orally, can stabilize or cause regression of leukoplakia, but their use is limited by side effects, including dry skin, chapped lips, and potential liver toxicity. Topical retinoids, applied directly to the lesion, aim to reduce systemic side effects, though their efficacy is limited. Other chemopreventive agents investigated include antioxidants like beta-carotene and various anti-inflammatory agents. While these drugs can lead to clinical improvement, lesions frequently recur once medication is stopped, confirming their role as a management tool rather than a permanent solution.
Preventing Recurrence and Maintaining Oral Health
Preventing recurrence is a fundamental component of long-term leukoplakia management, given that recurrence rates can be high even after successful removal. The most impactful preventative step is the permanent cessation of all forms of tobacco use, which is a major causative factor. Significant reduction or elimination of heavy alcohol intake is strongly recommended, as the combination of tobacco and alcohol compounds the risk of malignant transformation.
After any form of treatment, a rigorous and frequent follow-up schedule, known as surveillance, is mandatory. The frequency of these examinations is determined by the initial dysplasia grade and the clinical features of the lesion, but they may range from every few months to annually for many years. This close monitoring allows for the early detection of any recurrence or signs of malignant change. Maintaining excellent general oral hygiene and a diet rich in fruits and vegetables may also help mitigate the risk of recurrence by promoting a healthy oral environment.