Which of the following is NOT a common tobacco-associated cancer site?

• A. Gingiva
• B. Anterior 2/3 of tongue
• C. Buccal mucosa
• D. Posterior pharynx

Answer: (D)

Tobacco-related cancers in the mouth arise most where the mucosa is directly in contact with the product. Repeated exposure and irritation from chewing tobacco or from smoke affect the front part of the mouth most—the gingiva, the buccal mucosa, and the anterior two-thirds of the tongue—so these sites show the strongest association with tobacco use. The posterior pharynx sits further back and is less directly exposed to tobacco in daily use, so cancers there are not as tightly linked to tobacco as the other sites. While tobacco can contribute to cancers in the oropharynx and hypopharynx, those regions are less commonly tied to tobacco exposure than the listed anterior sites. Therefore, the posterior pharynx is not a common tobacco-associated cancer site.