Comparison of oral carcinomas in smokeless tobacco users and nonusers.

Biopsy reports of squamous cell carcinoma (SCC) and verrucous carcinoma (VC) were retrospectively evaluated to determine the prevalence of smokeless tobacco (ST) use and to ascertain if any clinical or histologic differences existed when comparing ST users with nonusers. Of the 874 SCC cases, 12 patients (1.4%) were ST users as compared with 7.7% (10 of 129) of the VC patients. The carcinomas in ST users, either SCC or VC, were diagnosed at a later age and were more likely to occur in the buccal mucosa/vestibule area. The SCCs in ST users were more often histologically well differentiated. Because of the anatomic site predilection, it appears probable that ST use is a causative factor in the development of some cases of oral carcinoma.