Clinicopathological behaviour of multiple oral dysplastic lesions compared with that of single lesions.

Oral precancerous lesions may be solitary or multifocal, the latter being difficult to manage because of extensive field change. The aim of this study was to characterise differences in clinicopathological features, proliferative labelling indexes for cyclin A, cyclin B1, and Ki67, and clinical outcome 5 years after laser resection in a group of patients presenting with single and multiple oral precancerous lesions. Ninety-six patients with 132 lesions (78 single and 18 multiple) were recruited, and there were no significant differences between those with single and multiple lesions with respect to age, sex, smoking, or alcohol consumption, although multiple lesions were significantly more common in smokers who ate little fruit and vegetables (p=0.02). Clinically, most lesions were leukoplakia, with ulcerated or exophytic lesions appearing singly. There were significant differences in site, single lesions being most common on the floor of the mouth and the ventrolateral tongue, and multiple lesions preferring the buccal mucosa (p=0.0002). The most severe dysplasia was seen in single lesions (p=0.001) with labelling indexes for cyclin A and Ki67 being significantly higher in these (p=0.04 and p=0.01, respectively). Oral squamous cell carcinoma developed in 3/78 single lesions and 4/18 multiple ones. There are distinct differences between single and multiple lesions that have implications for the prophylaxis and management of oral cancer.