Risk of preneoplastic and neoplastic events in operated oral leukoplakias

We retrospectively analysed 167 consecutive patients with oral leukoplakias operated on by CO2 laser resection in the Day Hospital of the Istituto Nazionale Tumori in Milan from January 1981 to December 1988, with post-operative histological examination negative for cancer. Within 5 years there were 69 patients with at least one unfavourable event. First unfavourable events were: 31 local relapses, 27 new leukoplakias, 5 oral carcinomas and 6 other neoplasms elsewhere. To identify possible prognostic factors we recorded age, sex and history of previous oral leukoplakias or head and neck cancers; also number, site, size and type of lesion; as well as tobacco and alcohol consumption and oral hygiene. The Cox regression model was employed to compare disease-free survival between different patient groups, both by univariate and multivariate analysis. From this analysis it emerges that age of operated patients and size of resected lesion are significantly predictive for development of relapses, new leukoplakias and carcinomas.