Carcinoma of the lip, predominantly on the lower lip, occurs in approximately 3,600 persons per year. Epidemiologically, these tumors behave akin to squamous cell carcinoma of the skin, and most are related to sun exposure, although chronic direct exposure to tobacco (i.e., the location where a pipe or cigarette is habitually held) is also associated with an increased risk of carcinoma of the lip.[24,25,26] Men have a higher risk of lip cancer than women. This has been attributed to tobacco use, greater occupational exposure to sunlight among men, and possibly due to the shielding effect of lipstick in women.
Interventions Associated With a Decreased Risk of Oral Cancer
Avoidance and cessation of tobacco use
The cessation of cigarette smoking is associated with a 50% reduction of risk of developing oral cancer within 3 to 5 years  and a return to a normal level of risk for development of oral cancer within 10 years. Dentists and other health professionals can play an integral role in smoking cessation advice and encouragement.
Dentists can also participate in the full scope of pharmacological and behavioral interventions for smoking cessation. A study has shown that only 25% of tobacco users report receiving advice to quit tobacco use from their dentist, a proportion less than that received from their physician. There was a dramatic increase in the use of cigars of about 250% during the period between 1993 and 1998  and heavy cigar use is particularly associated with oral cancer development.
Interventions With Inadequate Evidence as to Whether They Reduce Risk of Oral Cancer
Alcohol avoidance and cessation
Because alcohol is associated with oral cancer in a dose-dependent fashion,[9,11,31,32] it is believed that cessation or avoidance of alcohol would result in a lower incidence of oral cancer. The evidence is inadequate, however, of reduced oral cancer among people who have stopped consuming alcohol.
Avoidance of HPV infection
Association with HPV 16–positive squamous cell carcinoma of the head and neck (SCCHN) is independently associated with several measures of sexual behavior, including number of self-reported oral sex partners, and exposure to marijuana, but not with cumulative measures of the usual risk factors of tobacco smoking, alcohol drinking, and poor oral hygiene.[16,33] Additionally, marijuana use may interact with high-risk HPV infection to promote SCCHN. Direct evidence is not available to determine if restricting these exposures will impact overall incidence or outcome of oral cancer.