The effect of smoking and drinking in oral and pharyngeal cancers: a case-control study in Uruguay.

In the time period 1988-2000, a case-control study on oral and pharyngeal cancers was conducted among men in Montevideo, Uruguay. The study included 776 cases and 1501 controls. The cases were distributed by site in oral cancers (335 patients) and pharyngeal cancers (441 patients). Odds ratios for smoking were higher among participants with pharyngeal cancers compared with those with oral carcinomas, but there was no significant heterogeneity. On the contrary, alcohol drinking displayed statistically higher risks among those with pharyngeal carcinomas compared with patients with oral cancer (P-value for heterogeneity=0.01). The effect of alcohol was particularly strong for cancers of the hypopharynx. Our results raise the possibility that oral and pharyngeal carcinomas are in fact different entities. Further studies are needed in order to clarify this important point.