His comment is only accurate if you compare it to melanomas that can occur in the mouth as well on the exterior of the body, and are not necessarily correlated to sun exposure. (Dermatologists that know what they are doing even look between your toes for it). Melanomas are not that common in the mouth, but when the do occur there, have a very low survival rate. SCC is responsible for the overwheming majority of deaths in oral cancer because it occurs the most frequenty, about 85% of the time.